Chapter 13
Questions
1) What’s heredity?
Heredity is the transmission of traits from parents to offspring.
2) What’s genetics?
Genetics is the scientific study of heredity.
3) What’s locus?
Locus is the physical location of a gene in a chromosome.
Factor
1) Reproduction is a method of copying genes to pass them on to offspring. Two main types:
Asexual reproduction Sexual reproduction
2)
1. Heredity: The transmission of traits from parents to offspring.
2. Gene: The DNA for a trait.
3. Locus: The physical location of a gene in a chromosome.
4. Reproduction: A method of copying genes to pass them on to offspring.
5. Diploid: 2 sets of chromosomes which is most common in somatic cells.
6. Haploid: 1 set of chromosomes. Number in the gametes or sex cells.
7. Crossing-over: The exchange of sister chromatids material during synapsis. It
occurs ONLY in prophase I.
8. Chiasmata: The point of contact where two chromosomes are crossing-over.
9. Synapsis: Tetrad formation or genetic rearrangement.
10. Interkinesis: No DNA synthesis occurs.
http://www.youtube.com/watch?v=D1_-mQS_FZ0
2010年1月15日星期五
chapter 12
Chapter 12
1) What’s genome?
It’s the cell's hereditary endowment of DNA. It usually packaged into chromosomes for manageability.
2) What’s chromosome?
It is made of a DNA and protein complex called Chromatin.
3) What’s the structure of chromosome?
At cell division, each chromosome has been duplicated. The duplicated chromosome consists of two sister chromatids.
Factor
1) There are G2 of interphase, prophase, prometaphase, metaphase, anaphase and telophase and cytokinesis in the mitotic division of an animal cell.
2) In the interphase, there are G1 which is the first gap, S which is synthesis, G2 which is second gap.
3) In G1, Cell grows and carries out regular biochemical functions. When the DNA is replicated or synthesized. Chromosomes are replicated and then Cell completes preparations for division.
4) Mitosis is division of replicated chromosomes. Cytokinesis is division of the cell’s cytoplasm.
5) The purpose of mitotic is to divide the 2 copies of the DNA equally.To separate the sister chromatids into separate cells.
Diagram
In this diagram, we can see G1, G2 and DNA synthesis. G1 called checkpoint also called restriction point in mammalian cells. Places cells in a non-dividing phase called the Go phase. Most important checkpoint according to some.
Key term
1, Centromere: The point where two sister chromatids are connected.
1. Chromosomes: Made of a DNA and protein complex called chromatin; during cell
division, the chromatin becomes highly condensed into the chromosomes.
2. Gametes: Sperm and eggs which have half as many chromosomes as somatic
cells.
3. Somatic cells: All body cells except the reproductive cells each contain 46
chromosomes made up of two sets of 23.
4. Chromatin: A complex of DNA and associated protein molecules.
5. Mitosis: The division of the nucleus.
6. Cytokinesis: The division of the cytoplasm.
7. Centromere: The point where two sister chromatids are connected.
8. Centrosome: Structure present in the cytoplasm of animals cells, important during
cell division; functions as a microtubule-organizing center. A Centrosome has two
centrioles.
9. Cyclin-dependent kinases or Cdks: A protein kinase that is active only when
attached to a particular cyclin.
10. Transformation: The process that converts a normal cell to a cancer cell.
http://www.youtube.com/watch?v=qmTEiddrGOM
1) What’s genome?
It’s the cell's hereditary endowment of DNA. It usually packaged into chromosomes for manageability.
2) What’s chromosome?
It is made of a DNA and protein complex called Chromatin.
3) What’s the structure of chromosome?
At cell division, each chromosome has been duplicated. The duplicated chromosome consists of two sister chromatids.
Factor
1) There are G2 of interphase, prophase, prometaphase, metaphase, anaphase and telophase and cytokinesis in the mitotic division of an animal cell.
2) In the interphase, there are G1 which is the first gap, S which is synthesis, G2 which is second gap.
3) In G1, Cell grows and carries out regular biochemical functions. When the DNA is replicated or synthesized. Chromosomes are replicated and then Cell completes preparations for division.
4) Mitosis is division of replicated chromosomes. Cytokinesis is division of the cell’s cytoplasm.
5) The purpose of mitotic is to divide the 2 copies of the DNA equally.To separate the sister chromatids into separate cells.
Diagram
In this diagram, we can see G1, G2 and DNA synthesis. G1 called checkpoint also called restriction point in mammalian cells. Places cells in a non-dividing phase called the Go phase. Most important checkpoint according to some.
Key term
1, Centromere: The point where two sister chromatids are connected.
1. Chromosomes: Made of a DNA and protein complex called chromatin; during cell
division, the chromatin becomes highly condensed into the chromosomes.
2. Gametes: Sperm and eggs which have half as many chromosomes as somatic
cells.
3. Somatic cells: All body cells except the reproductive cells each contain 46
chromosomes made up of two sets of 23.
4. Chromatin: A complex of DNA and associated protein molecules.
5. Mitosis: The division of the nucleus.
6. Cytokinesis: The division of the cytoplasm.
7. Centromere: The point where two sister chromatids are connected.
8. Centrosome: Structure present in the cytoplasm of animals cells, important during
cell division; functions as a microtubule-organizing center. A Centrosome has two
centrioles.
9. Cyclin-dependent kinases or Cdks: A protein kinase that is active only when
attached to a particular cyclin.
10. Transformation: The process that converts a normal cell to a cancer cell.
http://www.youtube.com/watch?v=qmTEiddrGOM
chapter 11
Chapter 11
1) How does cell communicate?
Cells communicate with other cells by using signals.
2) Why does cell need communicate?
Because cells need to regulate themselves and Environmental Stimuli cells need to be able to respond to signals from their environment.
3) How many different signals are there?
There are local signals, they are paracrine signaling and synaptic signaling. And there is long distance (hormonal) signal.
Factors
!) There are three stages of cell signal. Reception is receiving signals. Transduction is passing on the signal. Response is cellular changes because of the signal.
2) In reception, The target cell’s detection of a signal coming from outside the cell. May occur by:
direct Contact and through signal molecules
3) direct contact means when molecules can flow directly from cell to cell without crossing membranes. For example, in plants there are plasmodesmata and in animals there are gap junctions.
4) Signal molecules are the actual chemical signal that travels from cell to cell. And they often water soluble, usually too large to travel through membranes. Double reason why they can’t cross cell membranes.
5) Reception molecules are usually made of protein. Change shape when bind to a signal molecule and transmits information from the exterior to the interior of a cell.
Summary
External signals are converted to responses within the cell. There are three stages of cell signaling. They are reception, transduction and response. Reception is a signaling molecule binds to a receptor protein, causing it to change shape. Transduction is cascades of molecular interactions relay signals from receptors to target molecules in the cells. Response is cell signaling leads to regulation of transcription ore cytoplasmic activities. Apoptosis integrates multiple cell-signaling pathways.
Diagram
In this diagram we can see there’re two kind of cell signaling, local signaling and long distance signaling. In local signaling there are paracrine signaling and synaptic signaling. And the long distance signaling is normally for hormonal.
Key terms
1. Signal transduction pathway: The process by which a signal on a cell’s surface is
converted to a specific cellular response.
2. Cell-cell recognition: Two cells in an animal may communicate by interaction
between molecules protruding from their surfaces.
3. Synaptic signaling: A nerve cell releases neurotransmitter molecules into a
synapse, stimulating the target cell. (Local signaling)
4. Local regulators: A secreted molecule that influences cells near where it is
secreted.
5. Hormone: In multicellular organisms, one of many types of secreted chemicals
that are formed in specialized cells, travel in body fluids, and act on specific target
cells in other parts of the body to change their functioning.
6. Reception: It is the target cell’s detection of a signaling molecule coming from
outside the cell.
7. Transduction: The binding of the signaling molecule changes the receptor protein
in some way, initiating the process of transduction.
8. Response: The transduced signal finally triggers a specific cellular response. In
cellular communication, the change in a specific cellular activity brought about by
a transduced signal from outside the cell.
9. Protein Kinase: An enzyme that transfers phosphate groups from ATP to a protein,
thus phosphorylating the protein.
10. Cyclic AMP: Also known as cAMP. It is a ring-shaped molecule made from ATP
that is a common intracellular signaling molecule (second messenger) in
eukaryotic cells. It is also a regulator of some bacterial operons.
http://www.youtube.com/watch?v=U6uHotlXvPo
1) How does cell communicate?
Cells communicate with other cells by using signals.
2) Why does cell need communicate?
Because cells need to regulate themselves and Environmental Stimuli cells need to be able to respond to signals from their environment.
3) How many different signals are there?
There are local signals, they are paracrine signaling and synaptic signaling. And there is long distance (hormonal) signal.
Factors
!) There are three stages of cell signal. Reception is receiving signals. Transduction is passing on the signal. Response is cellular changes because of the signal.
2) In reception, The target cell’s detection of a signal coming from outside the cell. May occur by:
direct Contact and through signal molecules
3) direct contact means when molecules can flow directly from cell to cell without crossing membranes. For example, in plants there are plasmodesmata and in animals there are gap junctions.
4) Signal molecules are the actual chemical signal that travels from cell to cell. And they often water soluble, usually too large to travel through membranes. Double reason why they can’t cross cell membranes.
5) Reception molecules are usually made of protein. Change shape when bind to a signal molecule and transmits information from the exterior to the interior of a cell.
Summary
External signals are converted to responses within the cell. There are three stages of cell signaling. They are reception, transduction and response. Reception is a signaling molecule binds to a receptor protein, causing it to change shape. Transduction is cascades of molecular interactions relay signals from receptors to target molecules in the cells. Response is cell signaling leads to regulation of transcription ore cytoplasmic activities. Apoptosis integrates multiple cell-signaling pathways.
Diagram
In this diagram we can see there’re two kind of cell signaling, local signaling and long distance signaling. In local signaling there are paracrine signaling and synaptic signaling. And the long distance signaling is normally for hormonal.
Key terms
1. Signal transduction pathway: The process by which a signal on a cell’s surface is
converted to a specific cellular response.
2. Cell-cell recognition: Two cells in an animal may communicate by interaction
between molecules protruding from their surfaces.
3. Synaptic signaling: A nerve cell releases neurotransmitter molecules into a
synapse, stimulating the target cell. (Local signaling)
4. Local regulators: A secreted molecule that influences cells near where it is
secreted.
5. Hormone: In multicellular organisms, one of many types of secreted chemicals
that are formed in specialized cells, travel in body fluids, and act on specific target
cells in other parts of the body to change their functioning.
6. Reception: It is the target cell’s detection of a signaling molecule coming from
outside the cell.
7. Transduction: The binding of the signaling molecule changes the receptor protein
in some way, initiating the process of transduction.
8. Response: The transduced signal finally triggers a specific cellular response. In
cellular communication, the change in a specific cellular activity brought about by
a transduced signal from outside the cell.
9. Protein Kinase: An enzyme that transfers phosphate groups from ATP to a protein,
thus phosphorylating the protein.
10. Cyclic AMP: Also known as cAMP. It is a ring-shaped molecule made from ATP
that is a common intracellular signaling molecule (second messenger) in
eukaryotic cells. It is also a regulator of some bacterial operons.
http://www.youtube.com/watch?v=U6uHotlXvPo
chapter 10
Chapter 10
Question:
1) Dose photosynthesis has different stages like cell respiration?
There are two stages of photosynthesis, they are light reaction and calvin cycle.
2) Where does the photosynthesis take place?
Photosynthesis happens in the chloroplast.
3) What’s the formula for photosynthesis?
6CO2 + 6H2O + light energy = C6H12O6+ 6O2
Factors:
1) Light reaction converts solar energy to chemical energy.
2) Calvin cycle begin by incorporating CO2 from the air into organic molecules already present in the chloroplast. This initial incorporation of carbon into organic compounds is known as carbon fixation. The Calvin cycle then reduces the fixed carbon to carbohydrate by the addition of electrons.
3) Light reaction is a form of electromagnetic radiation. Visible light has the right energy for use in Ps.
Diagram
In this diagram, the chloroplast, the thylakoid membranes are the sites of the light reactions, whereas the Calvin cycle occurs in the stroma. The light reaction use solar energy to make ATP and NADPH, which supply chemical energy and reducing power, respectively, to the Calvin cycle. Calvin cycle incorporates CO2 into organic molecules, which are converted to sugar.
Summary:
Photosynthesis converts light energy to the chemical energy of food. The light reactions convert solar energy to the chemical energy of ATP and NADPH. The Calvin cycle uses ATP and NADPH. The Calvin cycle uses ATP and NADPH to convert CO2 to sugar. Alternative mechanisms of carbon fixation have evolved in hot, arid climates.
Key term
1. Autotrophs: Self-feeders.
2. Heterotrophs: Biosphere’s consumers.
3. Chlorophyll: The green pigment located within chloroplasts.
4. Stomata: A microscopic pore surrounded by guard cells in the epidermis of leaves
and stems that allow gas exchange between the environment and the interior of the
plant.
5. Stroma: The dense fluid within the chloroplast.
6. Thylakoid: A flattened membranous sac inside a chloroplast. Thylakoids exist in
an interconnected system in the chloroplast and contain the molecular
“machinery” used to convert light energy to chemical energy.
7. Photophosphorylation: The lights reactions also generate ATP, using
chemiosmosis to power the addition of a phosphate group to ADP.
8. Carbon fixation: The initial incorporation of carbon from CO2 into an organic
compound by an autotrophic organism.
9. Cyclic electron flow: A route of electron flow during the light reactions of
photosynthesis that involves only photosystem I and that produces ATP but not
NADPH or oxygen.
10. Linear electron flow: A route of electron flow during the light reactions of
photosynthesis that involves both Photosystems (I and II) and produces ATP,
NADPH and oxygen. The net electron flow is from H2O NADP+.
http://www.youtube.com/watch?v=Q_1mxZdF2TY
Question:
1) Dose photosynthesis has different stages like cell respiration?
There are two stages of photosynthesis, they are light reaction and calvin cycle.
2) Where does the photosynthesis take place?
Photosynthesis happens in the chloroplast.
3) What’s the formula for photosynthesis?
6CO2 + 6H2O + light energy = C6H12O6+ 6O2
Factors:
1) Light reaction converts solar energy to chemical energy.
2) Calvin cycle begin by incorporating CO2 from the air into organic molecules already present in the chloroplast. This initial incorporation of carbon into organic compounds is known as carbon fixation. The Calvin cycle then reduces the fixed carbon to carbohydrate by the addition of electrons.
3) Light reaction is a form of electromagnetic radiation. Visible light has the right energy for use in Ps.
Diagram
In this diagram, the chloroplast, the thylakoid membranes are the sites of the light reactions, whereas the Calvin cycle occurs in the stroma. The light reaction use solar energy to make ATP and NADPH, which supply chemical energy and reducing power, respectively, to the Calvin cycle. Calvin cycle incorporates CO2 into organic molecules, which are converted to sugar.
Summary:
Photosynthesis converts light energy to the chemical energy of food. The light reactions convert solar energy to the chemical energy of ATP and NADPH. The Calvin cycle uses ATP and NADPH. The Calvin cycle uses ATP and NADPH to convert CO2 to sugar. Alternative mechanisms of carbon fixation have evolved in hot, arid climates.
Key term
1. Autotrophs: Self-feeders.
2. Heterotrophs: Biosphere’s consumers.
3. Chlorophyll: The green pigment located within chloroplasts.
4. Stomata: A microscopic pore surrounded by guard cells in the epidermis of leaves
and stems that allow gas exchange between the environment and the interior of the
plant.
5. Stroma: The dense fluid within the chloroplast.
6. Thylakoid: A flattened membranous sac inside a chloroplast. Thylakoids exist in
an interconnected system in the chloroplast and contain the molecular
“machinery” used to convert light energy to chemical energy.
7. Photophosphorylation: The lights reactions also generate ATP, using
chemiosmosis to power the addition of a phosphate group to ADP.
8. Carbon fixation: The initial incorporation of carbon from CO2 into an organic
compound by an autotrophic organism.
9. Cyclic electron flow: A route of electron flow during the light reactions of
photosynthesis that involves only photosystem I and that produces ATP but not
NADPH or oxygen.
10. Linear electron flow: A route of electron flow during the light reactions of
photosynthesis that involves both Photosystems (I and II) and produces ATP,
NADPH and oxygen. The net electron flow is from H2O NADP+.
http://www.youtube.com/watch?v=Q_1mxZdF2TY
2009年12月13日星期日
chapter 9
Chapter 9
Questions
1) What’s the formula of the cell respiration?
C6H12O6 + 6O2= 6CO2 + 6H2O + Energy (ATP+ heat)
2) What’s the difference between reducing agent and reduction?
The addition of electrons to another substance is reduction. The loss of electrons from one substance is called oxidation.
3) Where does the cell respiration take place?
There are three stages of respiration, they are glycolysis which takes place in cytosol, citric acid cycle and electron transport and chemiosmosis both of them happen inside of mitochondrion.
Factors:
1) The function of glycolysis is to split glucose and produce 2 NADH and 4 ATP. And it takes place in cytoplasm.
2) The function of Krebs cycle is oxidize pyruvic acid to CO2, it produce 4 NADH and 1 FADH2. It takes place in the mitochondria matrix.
3) The function of Electron transport and chemiosmosis is to convert NADH and FADH2 into ATP. It takes place in Mitochondria cristae.
4) ATP synthesis powered by the flow of proton back across the membrane, it called chemiosmosis.
5) Glycolysis produces 2 ATP, Krebs cycle produce 2 ATP and ETC produce about 32 or 34 ATP, so the complete cell respiration produce 36 or 38 ATP
Summary:
Catabolic pathways yield energy by oxidizing organic fuels. Glycolysis harvests chemical energy by oxidizing glucose to pyruvate. The citric acid cycle completes the energy yielding oxidation of organic molecules.During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis. Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen. Glycolysis and the citric acid cycle connect to many other metabolic pathways.
This chapter is mainly about cell respiration. There are three stages of cell respiration. They are produce ATP which is the energy will be used for photosynthesis. And also cell respiration produce water.
Diagram:
From this diagram we can see the three stages of cell respiration and their location and their functions. Glycolysis is the process that converts glucose to pyrucate. And all of the stages are producing ATP.
Key term:
1. Oxidation: LOSS of electrons, energy and hydrogens to carbons.
2. Reduction: GAIN of electrons, energy and hydrogens to carbon.
3. Phosphorylation: Adding a phosphate group to a molecule, and adding energy
to the molecule for chemical reactions.
4. Fermentation: A catabolic process that makes a limited amount of ATP from
glucose without an electron transport chain and that produces a characteristic
end product, such as ethyl alcohol or lactic acid.
5. Aerobic respiration: With oxygen. All three Rs steps.
6. Anaerobic respiration: Without oxygen. Glycolysis only.
7. Acetyl CoA: Acetyl coenzyme A; the entry compound for the citric acid cycle
in cellular respiration, formed from a fragment of pyruvate attached to a
coenzyme.
8. Substrate-level phosphorylation: It occurs when enzyme transfers a phosphate
group from a substrate molecule to ADP, rather than adding an inorganic
phosphate to ADP as in oxidative phosphorylation.
9. Oxidative phosphorylation: It is powered by the redox reactions of the electron
transport chain.
10. Glycolysis: Splitting glucose
http://www.youtube.com/watch?v=3y1dO4nNaKY&translated=1
Questions
1) What’s the formula of the cell respiration?
C6H12O6 + 6O2= 6CO2 + 6H2O + Energy (ATP+ heat)
2) What’s the difference between reducing agent and reduction?
The addition of electrons to another substance is reduction. The loss of electrons from one substance is called oxidation.
3) Where does the cell respiration take place?
There are three stages of respiration, they are glycolysis which takes place in cytosol, citric acid cycle and electron transport and chemiosmosis both of them happen inside of mitochondrion.
Factors:
1) The function of glycolysis is to split glucose and produce 2 NADH and 4 ATP. And it takes place in cytoplasm.
2) The function of Krebs cycle is oxidize pyruvic acid to CO2, it produce 4 NADH and 1 FADH2. It takes place in the mitochondria matrix.
3) The function of Electron transport and chemiosmosis is to convert NADH and FADH2 into ATP. It takes place in Mitochondria cristae.
4) ATP synthesis powered by the flow of proton back across the membrane, it called chemiosmosis.
5) Glycolysis produces 2 ATP, Krebs cycle produce 2 ATP and ETC produce about 32 or 34 ATP, so the complete cell respiration produce 36 or 38 ATP
Summary:
Catabolic pathways yield energy by oxidizing organic fuels. Glycolysis harvests chemical energy by oxidizing glucose to pyruvate. The citric acid cycle completes the energy yielding oxidation of organic molecules.During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis. Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen. Glycolysis and the citric acid cycle connect to many other metabolic pathways.
This chapter is mainly about cell respiration. There are three stages of cell respiration. They are produce ATP which is the energy will be used for photosynthesis. And also cell respiration produce water.
Diagram:
From this diagram we can see the three stages of cell respiration and their location and their functions. Glycolysis is the process that converts glucose to pyrucate. And all of the stages are producing ATP.
Key term:
1. Oxidation: LOSS of electrons, energy and hydrogens to carbons.
2. Reduction: GAIN of electrons, energy and hydrogens to carbon.
3. Phosphorylation: Adding a phosphate group to a molecule, and adding energy
to the molecule for chemical reactions.
4. Fermentation: A catabolic process that makes a limited amount of ATP from
glucose without an electron transport chain and that produces a characteristic
end product, such as ethyl alcohol or lactic acid.
5. Aerobic respiration: With oxygen. All three Rs steps.
6. Anaerobic respiration: Without oxygen. Glycolysis only.
7. Acetyl CoA: Acetyl coenzyme A; the entry compound for the citric acid cycle
in cellular respiration, formed from a fragment of pyruvate attached to a
coenzyme.
8. Substrate-level phosphorylation: It occurs when enzyme transfers a phosphate
group from a substrate molecule to ADP, rather than adding an inorganic
phosphate to ADP as in oxidative phosphorylation.
9. Oxidative phosphorylation: It is powered by the redox reactions of the electron
transport chain.
10. Glycolysis: Splitting glucose
http://www.youtube.com/watch?v=3y1dO4nNaKY&translated=1
2009年10月15日星期四
AP Biology Chapter 7
Chapter 7
Question:
1) What’s phospholipids means?
A phospholipid is an amphipathic molecule, meaning it has both a hydrophilic region and a hydrophobic region.
2) Where the protein is located?
There are integral proteins and peripheral proteins. Integral proteins penetrate they hydrophobic core of the lipid bilayer. Peripheral proteins are appendages loosely bound to the surface of the membrane, often to exposed parts of integral proteins.
2) What called a electrogenic pump?
3) A transport protein that generates voltage across a membrane is called an electrogenic pump.
Factors
1) In the fluid mosaic model, the membrane is a fluid structure with a “mosaic” of various proteins embedded in or attached to a double layer (bilayer) of phospholipids.
2) Cells recognize other cells by binding to surface molecules, often to carbohydrates, on the plasma membrane.
3) They dye diffuses from where it is more concentrated to where it is less concentrated called diffusing down a concentration gradient.
4) To pump a solute across a membrane against its gradient requires work; the cell must expend energy. Therefore, this type of membrane traffic is called active transport.
5) A single ATP-powered pump that transports a specific solute can indirectly drive the active transport of several other solutes in a mechanism called cotransport.
Summary：
Cellular membranes are fluid mosaics of lipids and proteins. Membrane structure results in selective permeability. Passive transport is diffusion of a substance across a membrane with no energy investment. Active transport uses energy to move solutes against their gradients bulk transport across the plasma membrane occurs by exocytosis and endocytosis.
Diagram
Question:
1) What’s phospholipids means?
A phospholipid is an amphipathic molecule, meaning it has both a hydrophilic region and a hydrophobic region.
2) Where the protein is located?
There are integral proteins and peripheral proteins. Integral proteins penetrate they hydrophobic core of the lipid bilayer. Peripheral proteins are appendages loosely bound to the surface of the membrane, often to exposed parts of integral proteins.
2) What called a electrogenic pump?
3) A transport protein that generates voltage across a membrane is called an electrogenic pump.
Factors
1) In the fluid mosaic model, the membrane is a fluid structure with a “mosaic” of various proteins embedded in or attached to a double layer (bilayer) of phospholipids.
2) Cells recognize other cells by binding to surface molecules, often to carbohydrates, on the plasma membrane.
3) They dye diffuses from where it is more concentrated to where it is less concentrated called diffusing down a concentration gradient.
4) To pump a solute across a membrane against its gradient requires work; the cell must expend energy. Therefore, this type of membrane traffic is called active transport.
5) A single ATP-powered pump that transports a specific solute can indirectly drive the active transport of several other solutes in a mechanism called cotransport.
Summary：
Cellular membranes are fluid mosaics of lipids and proteins. Membrane structure results in selective permeability. Passive transport is diffusion of a substance across a membrane with no energy investment. Active transport uses energy to move solutes against their gradients bulk transport across the plasma membrane occurs by exocytosis and endocytosis.
Diagram
In this diagram, I can see the different between hyperonic, isotonic and hypotonic. In hypotonic solution, the cells loose water molecules. In isotonic solution, the water molecule inside and outside of the cell are balanced. And in the hypotonic solution, the cells gain too much water which makes the cell explode.
Key terms
Osmosis: the diffusion of water across a selectively permeable membrane is called osmosis.
Isotonic: the isotonic to the cell means a cell without a wall, like an animal cell is immersed in an environment.
Hypertonic: when animal cell is immersed in a solution, it means hypertonic which the cell will lose water to its environment, shrivel and probably die.
Passive transport: the diffusion of a substance across a biological membrane is called passive transport.
Plasmolysis: as the plant cell shrivels, its plasma membrane pulls away from the wall, this phenomenon called plasmolysis.
Hypotonic: if we place the cell in a solution that is hypotonic to the cell, water will enter the cell faster than it leaves, and the cell will swell and lyse like an overfilled water ballon.
Active transport: to pump a solute across a membrane against its gradient requires work; the cell must expend energy, therefore, this type of membrane traffic is called active transport.
Facilitated diffusion: many polar molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane. This phenomenon is called facilitated diffusion.
Peripheral proteins: they are not embedded in the lipid bilayer at all; they are appendages loosely bound to the surface of the membrane, often to exposed parts of integral proteins.
Integral proteins: they penetrate the hydrophobic core of the lipid bilayer.
2009年10月14日星期三
AP Biology Chapter 5
Chapter 5
Questions
1) What’s condensation reaction?
Monomers are connected by a reaction in which two molecules are covalently bonded to each other through loss of a water molecule; this is known as a condensation reaction, specifically a dehydration reaction.
2) What’s the difference between saturated fat and unsaturated fat?
At room temperature, the molecules of a saturated fat such as butter are packed closely together, forming a solid. But at room temperature, the molecules of an unsaturated fat such as this olive oil cannot pack together closely enough to solidify because of the kinks in some of their fatty acid hydrocarbon chains.
3）what’s phospholipids?
Phospholipids are essential for cells because they make up cell membrane.
Factors
1） The simplest carbohydrates are the Monosaccharides, also known as simple sugars. Disaccharides are double sugars consisting of to monosaccharides joined by a covalent bond.
2） Depending on the location of the carbonyl group, a sugar is either an aldose (aldehyde sugar) or a ketose (ketone sugar).
3) Some polysaccharides serve as storage material, hydrolyzed as needed to provide sugar for cells. Other polysaccharides serve as building material for structures that protect the cell or the whole organism.
4) Lipids are the one class of large biological molecules that does not include true polymers, and they are generally not big enough to be considered macromolecules.
5) All proteins share three superimposed levels of structure, known as primary, secondary, and tertiary structure. A fourth level, quaternary structure, arises when a protein consists of two or more polypeptide chains.
Summary:
Macromolecules are polymers, build from monomers. Carbohydrates serve as fuel and building material. Lipids are a diverse group of hydrophobic molecules. Proteins have many structures, resulting in a wide range of functions. Nucleic acids store and transmit hereditary information.
Diagram
When a bond forms between two monomers, each monomer contributes part of the water molecule that is lost: one molecule provides a hydroxyl group (-OH), while the other provides hydrogen (-H). This reaction can be repeated as monomers are added to the chain one by one, making a polymer.
Questions
1) What’s condensation reaction?
Monomers are connected by a reaction in which two molecules are covalently bonded to each other through loss of a water molecule; this is known as a condensation reaction, specifically a dehydration reaction.
2) What’s the difference between saturated fat and unsaturated fat?
At room temperature, the molecules of a saturated fat such as butter are packed closely together, forming a solid. But at room temperature, the molecules of an unsaturated fat such as this olive oil cannot pack together closely enough to solidify because of the kinks in some of their fatty acid hydrocarbon chains.
3）what’s phospholipids?
Phospholipids are essential for cells because they make up cell membrane.
Factors
1） The simplest carbohydrates are the Monosaccharides, also known as simple sugars. Disaccharides are double sugars consisting of to monosaccharides joined by a covalent bond.
2） Depending on the location of the carbonyl group, a sugar is either an aldose (aldehyde sugar) or a ketose (ketone sugar).
3) Some polysaccharides serve as storage material, hydrolyzed as needed to provide sugar for cells. Other polysaccharides serve as building material for structures that protect the cell or the whole organism.
4) Lipids are the one class of large biological molecules that does not include true polymers, and they are generally not big enough to be considered macromolecules.
5) All proteins share three superimposed levels of structure, known as primary, secondary, and tertiary structure. A fourth level, quaternary structure, arises when a protein consists of two or more polypeptide chains.
Summary:
Macromolecules are polymers, build from monomers. Carbohydrates serve as fuel and building material. Lipids are a diverse group of hydrophobic molecules. Proteins have many structures, resulting in a wide range of functions. Nucleic acids store and transmit hereditary information.
Diagram
When a bond forms between two monomers, each monomer contributes part of the water molecule that is lost: one molecule provides a hydroxyl group (-OH), while the other provides hydrogen (-H). This reaction can be repeated as monomers are added to the chain one by one, making a polymer.
Key terms
Monosaccharide: The simplest carbohydrates.
Glucose: Most common monosaccharide.
Sucrose: The most prevalent disaccharide.
Lipid: they are the one class of large biological molecules that does not include true polymers, and they are generally not big enough to be considered macromolecules.
Fatty acid: a long carbon chain carboxylic acid.
Polypeptide: polymers of amino acids are called polypeptides.
Amino acids: its organic molecules possessing both carboxyl and amino groups.
Cholesterol: It’s a common component of animal cell membranes and is also the precursor from which other steroids are synthesized.
Glycogen: animals store a polysaccharide called glycogen, a polymer of glucose that is like amylopectin but more extensively branched.
Polynucleotide: nucleic acids are macromolecules that exist as polymers called polynucleotide.
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