Bio2 Flashcards

Question

2.3 State the formula for the calculation of BMI.

Answer 1

weight (kg) / height (m) ^2 (squared)

Answer 2

Ribose will have two OH's on the bottom facing downwards, while glucose will have H and OH (from left to right), and deoxyribose will have OH and H (from left to right)

Answer 3

Amino acids are linked together by condensation to form polypeptides with a peptide bond formed. The OH- from the carboxylic group of one amino acid, and a hydrogen from the second amino acid's amine group form a water molecule. A peptide bond is created between a carbon of the first amino acid and the nitrogen of the second amino.

Answer 4

There are 20 different amino acids in polypeptides synthesized on ribosomes. The 20 different amino acids differ in R group, and can be linked together in any sequence giving a huge range of possible polypeptides. For a polypeptide of n amino acids, there are 20 ^n possible sequences.

Answer 5

The amino acid sequence of polypeptides is coded for by genes. DNA (genes) codes for making proteins by having its instructors transcribed into mRNA, and the ribosomes then translate the mRNA codes into polypeptide sequences in the process of synthesis. Ribosomes are present in cytoplasm and the rER. A protein may consist of a single or any number of polypeptides. The key is that the function only begins when the correct polypeptides combine together. protein: a molecule that has function.

Answer 6

The amino acid sequence determines the three-dimensional conformation of a protein. The specific structure of amino acids forms polypeptides, and their properties determine how a polypeptide folds up into a protein. primary structure: a sequence of amino acids. secondary structure: in 2 possible stable sequences of alpha helices or beta pleated sheets and are held together due to hydrogen bonds. tertiary structure: the alpha helices or beta pleated sheets fold up due to interactions in the R group. quaternary structure: found in proteins that consist of more than one polypeptide chain linked together.

Answer 7

Living organisms synthesize many different proteins with a wide range of functions. Rubisco, insulin, immunoglobulins, rhodopsin, collagen and spider silk as examples of the range of protein functions. S Structure: proteins of more complex structure can provide tensile strength, which are a component on some parts of the body: collagen, spider silk. H Hormones: chemically diverse regulatory substance used to regulate body reactions: insulin I Immunity: make huge numbers of antibodies that helps fight viruses and bacteria: immunoglobins T Transport: transports molecules around the body: haemoglobins S Sensation: acts as receptors, act as binding sites in membranes: rhodopsin, Sodium Potassium pump M Movement: muscle contractions used in locomotion and transport around the body: actin, myosin E Enzymes: catalyses specific chemical reactions: rhodopsin, needed in photosynthesis.

Answer 8

Each individual organism has unique DNA. This explains why humans are all a little different from each other; as DNA is the genetic code for proteins. It makes sense that if every organism has unique DNA, then every organism also has a unique set of proteins as well.

Answer 9

Denaturation of proteins by heat or by deviation of pH from the optimum. Temperature -heat disrupts the hydrogen and covalent bonds between molecules -as these bonds are broken, the protein will begin to unfold and lose its capacity to function as intended -therefore disrupts the structure and function of the protein. -temperatures at which proteins denature may vary, but most human proteins function optimally at body temperature (~37°C) pH -amino acids are posesses both negatively (COO-) and positively (NH3+) charged regions -changing the pH will alter the charge of the protein, which in turn will alter protein solubility and overall shape -all proteins have an optimal pH which is dependent on the environment in which it functions (e.g. stomach proteins require an acidic environment to operate, whereas blood proteins function best at a neutral pH)

Answer 10

Enzymes have an active site to which specific substrates bind. Most enzyme reactions occur when the substrates are dissolved in water with random motion and each molecule moving separately. 1. Specificity: only a substrate is capable of binding to a particular enzyme's active site as they complement each other in therms of both shape and chemical properties. 2. Needs to collide with enough energy (needs to have enough thermal energy to create activation energy) 3. Chemical properties/charges of active site attract the substrate 4. Active site change into different chemical substances through a conformational change. (induced fit model, some can catalyze multiple reactions) 5. Products separate from the active site; leaving it vacant for substrates to bind to it again.

Answer 11

Temperature, pH and substrate concentration affect the rate of activity of enzymes. pH: all enzymes have an optimal pH value; when pH value is beyond optimal range, it can change the charges on R groups, breaking ionic bonds within the enzyme and causing a change in shape, leading to denaturation. temperature: a low temperature consists of a less kinetic energy, which the chance of the substrate binding to the enzyme decrease. an increase in thermal energy can increase collision; however, temperature beyond optimal range of enzyme will disrupt the bonds in enzymes, hence changing the shape and lead to denaturing substrate concentration: an increase in substrate concentration can increase enzyme activity as each active site of each enzyme is saturated and is thus working as fast as is possible. however, it will eventually plateau, because it reaches its maximum rate.

Answer 12

Enzymes can be denatured when the structure it changes, and it directly impacts its function, causing inability to function properly. Enzymes can be denatured through an extreme temperature or pH. Temperature: a high thermal energy can disrupt and destroy the hydrogen bonds in between enzymes, causing it to be denatured pH: changing the pH will alter the charge of the enzyme, which in turn will alter protein solubility and overall shape; changing the shape or charge of the active site will diminish its ability to bind the substrate, abrogating enzyme function

Answer 13

Detergents: contain proteases and lipase to help breakdown protein and fat stains. Textiles: in industry is being polished by enzymes. Food industry: fructose is used as a sweetener.

Answer 14

Lactase can be immobilized (attached to something so movement is restricted) in alginate beads and experiments can then be carried out in which the lactose in milk is hydrolysed. 1. Concentration of substrate can be increased manually to increase the rate of reaction. 2. Recycled enzymes can be used repeatedly and are easy to separate from the reaction mixture 3. Separation of products is straight forward (can also be stopped at the right time) Advantages of lactose free products: 1. Suitable for lactose intolerant groups 2. prevents crystallisations in ice creams 3. faster production in yogurts and cheeses (bacteria ferments monossacharide more readily) 4. increases sweetness in the absence of artificial sweeteners (monosaccharides are sweeter tasting)

Answer 15

Nucleic acids are the genetic material of the cell, it is composed of nucleotides. Nucleotides are always composed of: 1. A phosphate backbone 2. Nitrogenous base 3. 5 carbon pentose sugar -phosphate is in the left -pentose sugar is in the middle -nitrogenous base is on the right. -to link nucleotides together into a chain -covalent bonds are formed between the phosphate of one nucleotide and pentose sugar of the next nucleotide, which should be either on the top or the bottom of the phosphate, forming a strong phosphate backbone. -covalent bonds also attach the parts within a nucleotide.

Answer 16

DNA differs from RNA in the number of strands present, the base composition, and the type of pentose. 1. RNA is constructed by ribose, while DNA is constructed by deoxyribose. The difference between these two is that RNA have one extra oxygen. 2. DNA and RNA both have 4 nitrogenous bases, the only difference is that DNA has thymine, while RNA has Uracil. 3. DNA has the structure of a double helix (connected by H bonds between bases), while RNA is single stranded (one strand of nucleotide)

Answer 17

DNA is a double helix made of two antiparallel strands of nucleotides linked by hydrogen bonding between complementary base pairs. 1. The two strands of the DNA are both a chain of nucleotides. -the phosphate group of one nucleotide attaches to the sugar of another nucleotide (at the 3' hydroxyl (-OH) group) -results in a phosphodiester bond forming between the two nucleotides (and water is produced as a by-product) -successive condensation reactions result in the formation of long polynucleotide strands 2. DNA has a double helix shape. This is because there are two strands and each is in a spiral form. -in order for the bases to be facing each other and thus able to pair, the strands must be running in opposite directions -the two strands of DNA are described as being antiparallel -the two strands of DNA are antiparallel because they occur in opposite directions. -on one strand the number 5 carbon is on top. On the other strand the number 3 carbon is on top -as the antiparallel chains lengthen, the atoms will organise themselves into the most stable energv configuration -this atomic arrangement results in the double- stranded DNA forming a double helix (~10 - 15 bases per twist) 3. The nitrogenous base of the nucleotides stick out side ways, in which Hydrogen bonds occur between complementary bases, wounding the two strands together into a double helix. **A and T are complementary bases and are connected by two hydrogen bonds. C and G are complementarv bases and are connected by three hydrogen bonds

Answer 18

Their model showed: 1. A double helix, and the strands are antiparallel. 2. Pair via complementary base pairing. 3. The outer edges of bases remain exposed (allows access to replicative & transcriptional proteins)

Answer 19

The final construction of a correct DNA molecule owed heavily to the X-ray crystallisation data provided by Rosalind Franklin, which was shared without permission. Her data confirmed arrangement of DNA strands into helical structure, and she is now recognized as a key contributor to the elucidation of DNA structure.

Answer 20

**Use circles, pentagons and rectangles to represent phosphates, pentoses and bases

Answer 21

*Nitrogenous bases face inside Oxygen molecule points upward on the left, and downward on the right. *Phosphate backbone faces outside Note the two strands have carbons numbered in the opposite direction. Also note the hydrogen bonds between complementary bases. All other bonds in this molecule are covalent bonds In diagrams of DNA structure, the helical shape does not need to be shown, but the two strands should be shown antiparallel. Adenine should be shown paired with thymine and guanine with cytosine, but the relative lengths of the purine and pyrimidine bases do not need to be recalled, nor the numbers of hydrogen bonds between the base pairs.

Answer 22

The replication of DNA is semi-conservative and depends on complementary base pairing. Semi-conservative means that each of the two molecules of DNA formed in replication has one strand of the original DNA molecule. The other strand of the new DNA molecule is new. This new strand is formed from free nucleotides in the nucleus. The two strands of DNA are chemically bound by hydrogen bonds between adenine (A) and thymine (T), and between cytosine (C) and guanine (G). Semi-conservative is necessary because it is important to include the parental strand in order to minimize mistakes in DNA replication

Answer 23

1. Helicase unwinds the original DNA strand by breaking the hydrogen bonds the middle between the complementary base pairs. -the two strands of the parent DNA molecule must separate so that each can serve as a template for the new DNA strands that are being built. 2. After the unzipping of DNA, the complementary base pairs of the two strands are exposed, in which DNA polymerase comes in to link new nucleotides to the existing template. The two newly formed DNA will be identical, because nucleotides with the nitrogenous base A always pair with nucleotides with the nitrogenous base T. The same is true for C and G.

Answer 24

They wanted TOK ow whether the DNA is replicated conservatively, semi-conservatively, or if it’s dispersive. 1. They cultivated E Coli and allowed the first generation to replicate their DNA in Nitrogen 15 labelled medium. The DNA was spun down a centrifuge, and it appears that all the DNA consists of Nitrogen 15. 2. They put the 15N labelled E Coli DNA into 14N (lighter nitrogen) for the second generation to replicate. The DNA was then spun down the centrifuge again, and it showed a mixture between 15N and 14N, indicating that one strand of the DNA was 15N while the other strand was 14N 3. The same DNA was put into 14N to replicate for the third time. After spinning it down the centifuge, it showed both a mixture of 15N and 14N AND a mixture of only 14N. This results indicated that the originally 15N 14N DNA was unzipped, and that the 14N strand formed a new DNA by creating another 14N strand; while the 15N strand formed a new DNA by creating another 14N strand. As the process continued, the mixture of 15N and 14N DNA decreased (because there was only 2 strands of 15N DNA from the first generation), and the 14N and 14N mixture increased (because it was consistently placed in 14N solution for DNA replication. 15N strand formed a new DNA by creating another 14N strand.

Answer 25

Transcription is the synthesis of mRNA copied from the DNA base sequences using RNA polymerase. 1. RNA polymerase binds to a site of DNA at the start of the gene. 2. Moves along the gene, separating the DNA into two strands while only sticking to the sense strand, and starts pairing up RNA nucleotides. (so in this case uracil is paired up with adenine instead of thymine) 3. RNA polymerase forms covalent bonds between the RNA nucleotides. 4. RNA polymerase separates from DNA and double helix reforms. The DNA is then transcribed by synthesizing one strand of RNA>

Answer 26

Translation is the synthesis of polypeptides on ribosomes, using the transcribed Original D RNA b. messenger/mRNA attaches to ribosome (small unit); c. many ribosome/polyribosomes bind to same mRNA; d. (mRNA) carries codons/triplet of bases each coding for one amino acid; e. transfer/tRNA each have specific anticodon; f. tRNA carries specific amino acid; g. tRNA anticodon binds to codon in the mRNA; h. to corresponding triplet base/codon by complementary base pairing / OWTTE; i. a second tRNA (anticodon) binds to next codon; J. two amino acids bind together / peptide linkage is formed; k. first tRNA detaches; I. ribosome moves along mRNA; m. another tRNA binds to next codon; n. continues until stop codon is reached; 0. stop codon has no corresponding tRNA (anticodon)/amino acid/causes release of polypeptide; Hence, the amino acid sequence of polypeptides is determined by mRNA according to the genetic code. Once the polypeptide is produced the mRNA-ribosomal complex breaks apart. The ribosome is then able to combine with a different mRNA to produce a totally different polypeptide.

Answer 27

Each three-base sequence of nucleotides along an mRNA molecule is called a codon and codes for a specific amino acid, which is located and transferred by the tRNA There are 64 codon possibilities for 20 amino acids, and it is common in almost all organisms.

Answer 28

Translation depends on complementary base pairing between codons on mRNA and anticodons on tRNA. Anticodons are a region on the tRNA, which pairs with the complementary mRNA codon. The difference in tRNA molecules is based on the anticodon present. Each tRNA attaches to a specific amino acid, depending on the anti-codon. By the complementary pairing of bases between codons and anticodons, amino acids are lined up in the exact sequence called for in the genetic code, allowing the proper polypeptide to be produced.

Answer 29

Taq DNA polymerase is used to produce multiple copies of DNA rapidly by the polymerase chain reaction (PCR). 1. Denaturation DNA sample is heated to 95C to break the hydrogen bonds between the two strands of the DNA. 2. Annealing DNA sample is cooled immediately to 54C, allowing the primers (short pieces of DNA that matches a target to be amplified, so that the DNA taq polymerase only copies that area) attach to the opposite ends of the target sequence. 3. Elongation Tag polymerase copies the two strands Tag polymerase is an enzyme isolated from the thermophilic bacterium Thermus aquatics, and can withstand high temperatures.

Answer 30

Because the 64 codons to generate amino acids is universal, genetic information is transferrable between species to produce human insulin. D 1. Scientists insert gene from humans that produces insulin into E Coli. 2. E Coli can then produce human insulin, and can be harvested, purified, and packaged for human Use. -this "recombinant" bacteria will produce the protein encoded by the human gene because the genetic code is universal. -scientists build the human insulin gene in the laboratory. -then they remove a plasmid from the bacteria insert the human insulin gene into the plasmid. -the "recombinant" plasmid is returned to the bacteria. -the "recombinant" bacteria are put in large fermentation tanks where they repeatedly divides and use the insulin gene to begin producing human insulin. -the insulin is then harvested from the bacteria, purified and used as a medicine for people.

Answer 31

**Unless otherwise noted, the genetic code table uses mRNA codons! If given the mRNA codon and asked to find the amino acid for which it codes: -find the mRNA codon in the genetic code table and the corresponding amino acid. If given the tRNA anticodon: -determine the complementary mRNA codon -then find the mRNA codon in the genetic code table and the corresponding amino acid. If given the antisense sequence -determine the complementary mRNA codon -find the mRNA codon in the genetic code table and the corresponding amino acid. If given the sense sequence: -determine the mRNA codon -then find the mRNA codon in the genetic code table and the corresponding amino acid.

Answer 32

Cell respiration is the controlled release of energy from organic compounds to form ATP through oxidation reactions. -oxidation process is slow because it breaks down one covalent bond at a time. -each step in the oxidation reaction of cell respiration is controlled by enzymes. -the small amounts of energy released are used to produce the ATP molecules. -slow process ensures that small amount of energy is released at a time. -important because if a large yield of energy is released at once, there will be an increase in heat. -if there is heat then not all energy will be converted into ATP, which is less efficient. -the increased heat produced could also very well damage the cell. ATP is then the molecule which provides the energy for all the life processes of the cell to occur.

Answer 33

ATP is the product of cell respiration, and is the form of energy used by the cell to carry out the life functions. -it is immediately available as source of energy after cell respiration. -consists of three COVALENTLY linked phosphate molecules. -last two phosphates are bonded by a high energy bond, which cell can easily break to and release the energy to carry out the necessary functions of the cell. -this process is called hydrolysis (ATP turns into ADP + Pi). Cell respiration uses energy stored in organic molecules to regenerate ATP from ADP + Pi (via oxidation)

Answer 34

Anaerobic respiration is the generation of energy without the use of oxygen. -gives only a small yield of ATP from glucose. -occurs in the cell cytoplasm. -requires 2 ATP molecules to start the process. Glycolysis: 1. Enzyme modifies 6 carbon glucose to make it in the state of unstable 2. A series of reactions split glucose into 2 pyruvate (3 carbon compounds) -the energy from the bonds that are broken in this process are used to generate 4 ATP molecules. -if no oxygen is present after the first part of anaerobic cell respiration called glycolysis, a process called fermentation will occur. -animal:pyruvate stays in the cytoplasm and in humans is converted into lactate which is the removed from the cell. -yeast: the pyruvate is converted into carbon dioxide and ethanol. In either case, no ATP is produced in the process AFTER glycolysis. **Note that if oxygen becomes available in human cells, the lactic acid (lactate) produced may be changed back to pyruvate and used in aerobic cell respiration. This is referred to as a reversible reaction.

Answer 35

Similarities: 1. Essential to life as it generates ATP and energy/ heat. 2. Both start with glucose. 3. Both start with the process of glycolysis. 4. Both produces pyruvate. Differences: 1. Aerobic respiration requires oxygen while anaerobic respiration does not. 2. Aerobic respiration produces a large yield of ATP over a longer period of time, and anaerobic respiration produces a small yield of of ATP in a short time period. 3. Aerobic respiration produces carbon dioxide and water. Anaerobic respiration produces lactate (lactic acid) in humans, and ethanol and carbon dioxide in yeast and plants. 4. Aerobic leads to Kreb's cycle and anaerobic leads to fermentation. 5. Anaerobic occurs in cytoplasm while aerobic occurs in mitochondria (pyruvate is transported to there).

Answer 36

Yeast carries out anaerobic respiration; Which produces ethanol and carbon dioxide; From the breakdown of sugars/monosaccharides/ carbohydrates (in the dough/grape juice); In wine fermentation, ethanol is the essential product making the juice into wine; Ethanol concentration rises in the ferment causing the process to stop/death of yeast; In bread making, carbon dioxide causes the dough/bread to rise; The ethanol evaporates during baking/heating/ cooking; Yogurt / Cheese - Bacteria produce lactic acid anaerobically, which modifies milk proteins to generate yogurts and cheeses

Answer 37

Lactate production in humans when anaerobic respiration is used to maximize the power of muscle contractions. Lactate production in humans occurs during intense muscle activity. Due to the intensity of the activity not enough oxygen can be delivered to the muscles. The result of this lack of oxygen delivery is maximum muscle contraction. However, the lactate produced will seriously limit the number of maximum muscle contractions, as it is poisonous. Lactate will be converted back into pyruvate with the presence of oxygen.

Answer 38

A respirometer is a simple apparatus that can measure the rate of respiration -measures the consumption of oxygen as an indication of the respiration rate. -in Tube A, the organism to be tested (or germinating seed) is positioned, and the tap is closed -the organism starts respiring, consuming 02 and producing CO2 and H2O. -the alkaline solution at the bottom of Tube A will absorb the CO2 -Tube B is the control where no 02 is used or CO2 produced because no living organism is present. -the capillary connecting the two tubes is a manometer. -he reduction in oxygen in Tube A will reduce the pressure in Tube A -and will move the coloured liquid in the manometer in the direction of Tube A, providing an indirect measurement of the oxygen consumed -allowing the rate (amount of oxygen consumed per time unit) to be calculated

Answer 39

Photosynthesis is the production of carbon compounds in cells using light energy.

Answer 40

Visible light ranges from red to violet and 400nm to 700nm. Violet has the shortest wavelength (400nm) while red has the longest wavelength (700nm). The colours with the shortest wavelengths possess the highest energy

Answer 41

Chlorophyll is a green pigment found in photosynthetic organisms and they are responsible for light absorption. This absorbed light energy in then used to convert carbon dioxide and water into carbohydrates such as glucose and oxygen. Chlorophyll absorbs red and blue light most effectively. The energy of the red and blue colors is then used in the production of glucose Chlorophyll reflects green light more than other colors.

Answer 42

Paper chromatography is a technique used to separate substances in a mixture based on the movement of the different substances up a piece of paper by capillary action. The pigment molecules migrate, or move up the paper, at different rates because of differences in: -solubility -molecular mass -variable hydrogen bonding with the chromatography paper. This is important because plants don't reply on only one pigment to absorb light. Two of the most common techniques for separating photosynthetic pigments are: Paper chromatography - uses paper (cellulose) as the stationary bed Thin layer chromatography - uses a thin layer of adsorbent (e.g. silica gel) which runs faster and has better separation -a stationary bed (e.g paper) is dipped into mobile phase, you might use ethanol as the solvent, or you may use propanone (acetone). **the mobile phase dissolves pigments, allowing them to travel up the paper strip. Varying colors in different areas of the chromatogram with different Rf values indicate separate pigments. Rf = distance travelled by sample/ distance travelled by solvent Method of paper chromatography: 1. a leaf is ground in a mortar and pestle, using a small amount of sand to help grind the sample and break down the cell walls. 2. a small amount of solvent is added, and the sample is ground up further to dissolve the pigments in the solvent. 3. when the solvent is dark green, let the solids settle and then pour off the solvent (which now contains the sample of pigments) into a small beaker or watch glass. 4. this step raises the concentration of the pigments in the solvent, which makes it easier to see the separated pigments once the chromatography is complete. 5. use a toothpick or very small paintbrush to apply the pigment sample to a spot that is at least 20 mm from the bottom of your paper or TLC strip. 6. situate the paper or TLC strip in a sample tube; ensure that the pigment sample is above the solvent at the beginning of the experiment

Answer 43

Photosynthesis can be split into 2 stages, light dependent reaction and light independent reaction. Light dependent reaction: Oxygen is produced in photosynthesis from the photolysis of water. 1. splitting of water to produce oxygen. Photolysis is the process in which energy from light is used to split water. When photolysis occurs oxygen gas is produced. Most of the oxygen is released into the atmosphere. Hydrogen is also produced. The hydrogen is used in later stages of photosynthesis. Light independent reaction: Energy is needed to produce carbohydrates and other carbon compounds from carbon dioxide. The energy from the absorbed colours of the visible light spectrum is used to build carbon compounds which include carbohydrates. 2. H+ combines with CO2 to form complex organic compounds. (carbs, amino acids, etc) Hence, the products of photosynthesis are: -oxygen -glucose

Answer 44

Earth's atmosphere: -amount of plants determine level of CO2 inside the atmosphere -which may lead to increase in global temperature and acidity of the rain Ocean: -Earth's oceans initially had high levels of dissolved iron (released from the crust by underwater volcanic vents) -When iron reacts with oxygen gas it undergoes a chemical reaction to form an insoluble precipitate (iron oxide) -When the iron in the ocean was completely consumed, oxygen gas started accumulating in the atmosphere. In D Rock deposition: -The reaction between dissolved iron and oxygen gas created oceanic deposits called banded iron formations (BIFs) -These deposits are not commonly found in oceanic sedimentary rock younger than 1.8 billion years old - This likely reflects the time when oxygen levels caused the near complete consumption of dissolved iron levels -As BIF deposition slowed in oceans, iron rich layers started to form on land due to the rise in atmospheric 02 levels dissolved iron levels

Answer 45

Temperature: -photosynthesis is controlled by enzymes -high temperature will cause denaturation Light intensity: -more light intensity = more chlorophyll are being photo activated (increase in reaction) -will eventually plateau when all chlorophyll are saturated with light. CO2 concentration -more reactant = more product = increase in rate -cuz CO2 is involved in the fixation of carbon atoms to form organic molecules.

Answer 46

Answer must include two explanations for full marks. Award [2 max] for one explanation. production of oxygen; (because) oxygen is a by product of the reaction; count bubbles of oxygen (from pondweed); measure the volume of oxygen; use of oxygen probe find oxygen concentration; or: measure carbon dioxide uptake; (because) carbon dioxide is a raw material of the reaction; measure colour change of pH indicator / other method; use of carbon dioxide probe to find carbon dioxide concentration; or: measure increase in biomass; (because products) used in production of cell walls and new tissue; harvest replicate samples at time intervals for biomass determination;

Answer 47

-amine A nitrogen atom bonded to two hydrogen atoms (-NH2) -carboxyl A carbon double bonded to an oxygen (=O) and a hydroxyl (-OH) -hydroxyl Polar covalent bond between an oxygen and a hydrogen (-OH). -phosphate A central phosphorus bonded to four oxygen atoms (-PO4). This functional group has a negative charge. -methyl A methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms - CH3

Answer 48

Metabolism is the web of all the enzyme- catalyzed reactions in a cell or organism. Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst, which is not consumed in the catalvzed reaction and can continue to act repeatedly. *Biological catalysts are called enzymes.

Answer 49

Anabolism: Constructing larger molecules from smaller subunits. Catabolism: Catabolism is the breaking down of large molecules into smaller subunits. Monomer: A small molecule that can bind with other molecules of the same type to form a large polymer. Polymer: A large molecule composed of many repeating monomer subunits.

Answer 50

Condensation: A chemical reaction in which two molecules (monomers) combine to form a larger molecule with the formation of water. Hydrolysis: A chemical reaction in which a polymer breaks apart into smaller subunits; addition of water is used to break the bonds.

Answer 51

Anabolism -uses eneray -condensation reaction -produces water -synthesis of macromolecues Catabolism -requires energy -hydrolysis -uses water -breakdown of macromolecules

Answer 52

-in the liver, ammonia (NH3, a toxic byproduct of protein metabolism) is converted to urea, which is excreted from the body via the kidneys. -urea can also be synthesis artificially in a reaction between ammonia and carbon dioxide

Answer 53

Lipids can be roughly organised into one of three main classes: Simple (neutral) lipids - Esters of fatty acids and alcohol (e.g. triglycerides and waxes) Compound lipids - Esters of fatty acids, alcohol and additional groups (e.g. phospholipids and glycolipids) Derived lipids - Substances derived from simple or compound lipids (e.g. steroids and carotenoids)

Answer 54

-in water, the oxygen has a greater "pull" on the shared electrons than the hydrogen atoms. -as a result, there is unequal sharing of the electrons -electrons are drawn closer to the oxygen. -as a result, the oxygen has a slightly negative charge -hydrogens have a slightly positive charge.

Answer 55

-water cohesion allows for surface tension, allowing some insects to stay on the surface of the water. -water cohesion creates a chain of water molecules that allows for the transport of water from the roots to the leaves of plants. -water cohesion is responsible for the high heat capacity of water, maintaining a relatively stable internal temperature and external environment for living organisms.

Answer 56

-adhesion is needed for water to move from the roots to the leaves of plants. -water sticks to the sides of the xylem wall through adhesion.

Answer 57

High specific heat capacity -takes a relatively large amount of heat energy to raise the temperature of water. -benefit because the temperature of large bodies of water remains relatively constant, protecting life from potentially lethal temperature fluctuations. High latent heat of vaporization -takes a relatively high amount of heat energy to vaporize water (convert from liquid to gas) -because hydrogen bonds must be broken. -as the water evaporates, the surface it leaves becomes cooler (because heat there is used as energy to caporize). -this is called evaporative cooling and allows organisms to cool with sweating. High boiling point -water boils at a relatively high temperature for a compound made of such light elements; -due to the hydrogen bonding between water molecules causing them to resist being pulled apart (which is what happens when water boils to become a gas). -without this, water would not be a liquid over much of the surface of the Earth and we would not have a liquid ocean.

Answer 58

-polar substances -ionically charged substances -hydrophilic molecules

Answer 59

-phosphate group negative charge found on a phosphate group makes it an ION. Water is attracted to ions, making them hydrophilic. -hydroxyl group There is a polar covalent bond between the O and H in a hydroxyl group. As a result, water is attracted, making molecules with many hydroxyl groups hydrophilic (such as glucose). -hydrocarbons If there are no charges and no polar covalent bonds, then water will not be attracted, making the molecule hydrophobic

Answer 60

The differences in thermal properties between water and methane arise from differences in polarity between the molecules: -water is polar and can form intermolecular hydrogen bonds (due to high electronegativity of oxygen atom) -methane is non-polar and can only form weak dispersion forces between its molecules (carbon has a lower electronegativity) This means water absorbs more heat before changing state (each H-bond has an average energy of 20 kJ/mol) -methane gas at room temp -water liquid at room temp -water has a significantly higher melting and boiling point -water has a higher specific heat capacity (energy required to raise the temperature of 1 g of substance by 1°C) -water has a higher heat of vaporisation (energy absorbed per gram as it changes from a liquid to a gas / vapour) -water as a higher heat of fusion (energy required to be lost to change 1 g of liquid to 1 g of solid at 0°C)

Answer 61

Carbon #1 of one glucose binds to carbon #4 of the other glucose Condensation is a chemical reaction in which two molecules are joined to make a larger molecule with the loss of water. An -H from the hydroxyl on carbon #1 of one monosaccharide combines with an -OH from the hydroxyl on carbon #4 of the other monosaccharide. The -H and OH combine to form water. A bond is formed with a C-O-C bridge between the two monosaccharides. The bond created is called glycosidic linkage.

Answer 62

energy storage / source of energy / respiration substrate (heat) insulation protection (of internal organs) water proofing / cuticle buoyancy (structural) component of cell membranes electrical insulation by myelin sheath (steroid) hormones glycolipids acting as receptors

Answer 63

Trans fat are a type of unsaturated fat that occur in small amounts in nature but became widely produced industrially from vegetable fats starting in the 1950s for use in margarine, snack food, and packaged baked goods and for frying fast food Use of trans fats in food is now banned in the USA.

Answer 64

A high BMI can be an indicator of obesity, which correlates to health problems, including: - Type II diabetes - Gallstones - Hypertension - Heart disease A low BMI can be an indicator of malnourishment. Note, use of BMI has limitations because it doesn't distinguish mass from fat, muscle or bone. Might misclassify healthy people as obese and visa versa.

Answer 65

# of bonds is the number of amino acids minus 1 # of waters created = the number of peptide bonds Ex: a polypeptide with 784 amino acids has 783 peptide bonds and formed 783 water molecules

Answer 66

A linear polymer consisting of a large number of amino-acids bonded together in a chain, forming part of (or the whole of) a protein molecule.

Answer 67

Look at the variable ("R") group If the R group has -OH or =O then it is polar and the amino acid will likely be HYDROPHILLIC If the R group is a hydrocarbon, then it is non- polar and the amino acid will likely be HYDROPHOBIC If the R group has a charge (+ or -) then the amino acid will likely be HYDROPHILLIC

Answer 68

There are innumerable ways that amino acids can combine to form polypeptides. The general formula for the number of theoretically possible different amino acid sequences of length n is 20^n.

Answer 69

gene is a sequence of DNA bases: DNA/gene codes for a specific sequence of amino acids/polypeptide; enzymes are proteins/composed of polypetides; sequence of amino acids determines tertiary structure/folding/shape of active site; change in the gene/mutation will affect the active site/function of an enzyme; enzymes are involved in replication/transcription of genes; enzymes are involved in synthesis of polypeptides;

Answer 70

fibrous proteins are strands/sheets whereas globular proteins are rounded; fibrous proteins (usually) insoluble whereas globular proteins (usually) soluble; globular more sensitive to changes in pH/ temperature/salt than fibrous; fibrous proteins have structural roles / other specific role of fibrous protein; globular proteins used for catalysis/transport/ other specific role of globular protein; another role of globular protein; named fibrous proteins e.g. keratin/fibrin/ collagen/actin/myosin/silk protein; named globular protein e.g. insulin/ immunoglobulin/hemoglobin/named enzyme; Do not accept statements about fibrous proteins having only secondary structure and globular proteins having only tertiary structure.

Answer 71

The following are specific examples of the different functions of proteins: Structure Collagen: A component of the connective tissue of animals (most abundant protein in mammals) Spider silk: A fiber spun by spiders and used to make webs (by weight, is stronger than kevlar and steel) Hormones Insulin: Protein produced by the pancreas and triggers a reduction in blood glucose levels Glucagon: Protein produced by the pancreas that triggers an increase in blood glucose levels Immunity Immunoglobulins: Antibodies produced by plasma cells that are capable of targeting specific antigens Transport Haemoglobin: A protein found in red blood cells that is responsible for the transport of oxygen Cytochrome: A group of proteins located in the mitochondria and involved in the electron transport chain Sensation Rhodopsin: A pigment in the photoreceptor cells of the retina that is responsible for the detection of light Movement Actin: Thin filaments involved in the contraction of muscle fibres Myosin: Thick filaments involved in the contraction of muscle fibres Enzymes Rubisco: An enzyme involved in the light independent stage of photosynthesis

Answer 72

the entire complement of proteins that is or can be expressed by a cell, tissue, or organism.

Answer 73

many proteins are soluble in water: solubility depends on what amino acids /R groups are present smaller proteins are more soluble than big ones proteins with many polar / hydrophilic amino acids / R groups are more soluble / soluble proteins with polar / hydrophilic amino acids / R groups on the outside are soluble example of a polar amino acid / group globular proteins are more soluble than fibrous proteins however, the solubility of proteins can be limited: solubility of proteins may also be affected by conditions (pH, temperature, salinity) denaturation makes proteins insoluble proteins do not form true solutions in water but colloidal solutions

Answer 74

Genome: the whole of the genetic information of an organism Proteome: the entire complement of proteins that is or can be expressed by a cell, tissue, or organism.

Answer 75

Denaturation is a structural change in a protein that results in the loss (usually permanent) of its biological properties

Answer 76

Most species use 20 amino acids for assembly of polypeptides. However, a few species use up to 22 amino acids. The additional two amino acids (selenocysteine and pyrrolysine) require alternative mechanisms for their incorporation to proteins.

Answer 77

Enzyme: Enzymes are proteins that act as a catalyst to bring about a specific biochemical reaction. Substrate: The substrate is the substance on which an enzyme acts. Active site: The active site is the region on the surface of the enzyme which binds to the substrate molecule

Answer 78

they increase rate of (chemical) reaction; remains unused/unchanged at the end of the reaction:lower activation energy; activation energy is energy needed to overcome energy barrier that prevents reaction: annotated graph showing reaction with and without enzyme; substrate joins with enzyme at active site; to form enzyme-substrate complex; active site/enzyme (usually) specific for a particular substrate; enzyme binding with substrate brings reactants closer together to facilitate chemical reactions (such as electron transfer); induced fit model / change in enzyme conformation (when enzyme-substrate/ES complex forms); making the substrate more reactive;

Answer 79

a particular yeast (growing in natural milk) contains lactase; biotechnology companies can grow/culture the yeast; lactase (an enzyme) is extracted from the yeast;natural milk contains lactose/milk sugar; when added directly to milk, lactase converts lactose into simpler forms; same effect when milk is passed past immobilized (on surface or beads) lactase; simpler forms of sugar (glucose and galactose) are easily absorbed (in the small intestine); a commercial market exists for lactose-free milk / lactose-free milk is example of biotechnology's economic impact; some people are lactose intolerant/cannot digest lactose in milk/have lost lactase activity in intestinal cells; consuming lactose-free milk allows lactose intolerant people to be nourished by milk without discomfort (abdominal cramps and diarrhoea); many Asians are lactose intolerant whereas less common among other groups (northern Europeans and some Africans); biotechnology produced in one part of world is more useful in another;

Answer 80

To denature means to destroy the characteristic properties of a protein (or other biological macromolecule) by heat, acidity, or other effects that disrupt its molecular shape.

Answer 81

The lactase used to produce lactose free dairy products is obtained from a yeast. The yeast is cultured and then the lactase is extracted and purified.

Answer 82

Possible manipulated variables include: Substrate concentration Enzyme concentration Temperature Source of enzyme pH Inhibitor presence Inhibitor type

Answer 83

Possible responding variables include: Enzyme reaction time (s) Enzyme reaction rate (s^-1) Amount of product Amount of substrate

Answer 84

Catalase is an enzyme that converts hydrogen peroxide (H202) to water (H2O) and oxygen gas (02, which bubbles out of solution) -the activity of catalase can be measured by measuring the amount of 02 formed in a set amount of time via one of the following methods: - time to float an enzyme saturated filter disc - H2O displacement in by formation of 02 gas - 02 gas bubble volume - change in pressure due to 02 gas- change in 02 levels with sensor

Answer 85

Pyrimidine: single ring nitrogenous bases Cytosine Thymine Uracil Purine: double ring nitrogenous bases Guanine Adenine

Answer 86

Adiacent molecules are oriented parallel to each other but oriented in opposite directions. In DNA, one strand runs 5' to 3' and the complementary strand unds 3' to 5'

Answer 87

A complete turn is when one strand circles back on itself. There are 10 base pairs per turn of the helix.

Answer 88

Charfaff determined that there are equal numbers of A and T bases and G and C bases in a DNA sample.

Answer 89

Watson figured out how the nitrogenous base pairs could fit within a DNA double helix while maintaining a constant helix diameter. Crick suggested that the DNA backbone was anti- parallel.

Answer 90

The structural organisation of the DNA molecule was correctly proposed in 1953 by James Watson and Francis Crick -these British scientists constructed models to quickly visualise and assess the viability of potential structures -their efforts were guided by an understanding of molecular distances and bond angles developed by Linus Pauling, and were based upon some key experimental discoveries: -DNA is composed of nucleotides made up of a sugar, phosphate and base - Phoebus Levene, 1919 -DNA is composed of an equal number of purines (A + G) and pyrimidines (C + T) - Erwin Chargaff, 1950 -DNA is organised into a helical structure. Rosalind Franklin, 1953 (data shared without permission) Making DNA Models -using trial and error, Watson and Crick were able to assemble a DNA model that demonstrated the following: -DNA strands are antiparallel and form a double helix access to replicative and transcriptional proteins) As Watson and Crick's model building was based on trial and error, a number of early models possessed faults: -the first model generated was a triple helix -early models had bases on the outside and sugar-phosphate residues in the centre -nitrogenous bases were not initially configured correctly and hence did not demonstrate complementarity DNA strands pair via complementary base pairing (A = T; C= G) -outer edges of bases remain exposed (allows

Answer 91

Single stranded A, U, G, C Ribose sugar

Answer 92

The 5' and 3' ends of a nucleic acid refer to the direction of the chain. In DNA. one strand will run from 5' to 3' and the complementary strand will run anti-parallel, from 3' to 5' The 5' end is identified by the presence of the phosphate group and the 3' end is identified as ending in the pentose sugar (ribose or deoxyribose).

Answer 93

Mathematical Models Use of math to describe and/or predict the behavior of a system Computer Models Computer programs that attempt to simulate the behavior of a system Physical Models Models of structures that can be carried, touched or heldlmages Diagrams used to represent a structure or process Analogy Comparisons for the purpose of explanation or clarification

Answer 94

A model is a representation of a phenomenon, object or idea. Models are used to explain difficult concepts or to have tangible visualizations of structures. Models can be used to make and test predictions and to understand processes that are not easily observed.

Answer 95

All models have limitations. -variations in size -simplification of complexity -may be static representations of moving structures/processes -do not represent all dimensions or variables

Answer 96

ensures that the DNA sequence remains consistent after DNA replication. This ensures that the genetic code remains intact between generations

Answer 97

The origin of replication is the sequence of DNA nucleotides at which replication is initiated.

Answer 98

Prokaryotic cells have 1 origin of replication (therefor one replication bubble with two replication forks) Eukaryotic cells have many origins of replication (therefor multiple replication bubbles that eventually fuse)

Answer 99

-DNA polymerase synthesises new strands from the two parental template strands -free deoxynucleoside triphosphates (nucleotides with 3 phosphate groups) align opposite their complementary base partner -DNA polymerase cleaves the two excess phosphates and uses the energy released to link the nucleotide to the new strand -DNA polymerase can only add new nucleotides to the 3' end of the growing daughter strand -the parent/template is read from 3' to 5 DNA polymerase builds a complementary strand of DNA from the parent/template strand. -the daughter strand is built from 5' to 3.

Answer 100

the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).

Answer 101

-the strand that is transcribed is called the antisense strand and is complementary to the RNA sequence -the strand that is not transcribed is called the sense strand and is identical to the RNA sequence (with T instead of U)

Answer 102

the process in which ribosomes in the cytoplasm or ER synthesize a specific amino acid chain, or polypeptide, based on the mRNA sequence (that had been transcribed from DNA).

Answer 103

Because there is no nucleus to separate the processes of transcription and translation, when bacterial genes are transcribed, their transcripts can immediately be translated by a ribosome in the cytoplasm. Transcription and translation are spatially and temporally separated in eukaryotic cells; transcription occurs in the nucleus to produce a mRNA which exits the nucleus and is translated in the cytoplasm on a free ribosome or at the endoplasmic reticulum (ER) on a bound ribosome

Answer 104

the rules used by all cells to translate information encoded within genetic material (DNA) into proteins. The code defines how sequences of three mRNA nucleotides, called codons, specify which amino acid will be added next during protein synthesis.

Answer 105

Messenger RNA (mRNA) carries the genetic information transcribed from DNA in the form of a series of three-nucleotide code ("codon"), each of which specifies a particular amino acid.

Answer 106

Ribosomal RNA (rRNA) associates with a set of proteins to form ribosomes. These complex structures, which physically move along an mRNA molecule, catalyze the assembly of amino acids into polypeptide chains.

Answer 107

a three-base sequence (three nitrogenous bases in a row) on mRNA, that functions to codes for a specific amino acid to be brought to the growing polypeptide during translation.

Answer 108

The genetic code is redundant, meaning more than one codon may specify a particular amino acid. For example, the codons CCC and CCG both code for the same amino acid, proline.

Answer 109

a three-base sequence on tRNA that is complementary to the mRNA codon to which it forms hydrogen bonds.

Answer 110

Prior to widespread use of gene transfer technology, insulin for diabetes was isolated from pig pancreases. Some benefits of using gene transfer technology to produce insulin are: -biotechnologically produced insulin is indistinguishable from human insulin produced in the pancreas and is therefore less likely to cause allergic reactions in diabetics. -large quantities of insulin can be produced at the same time. -the ethical issues for diabetics who could not use pig's insulin because of religious beliefs or vegetarianism are overcome. -this form of insulin is absorbed more rapidly than animal derived insulin thus showing its effectiveness in a shorter duration.

Answer 111

With minor exceptions, all life uses the same genetic code

Answer 112

-ATP is an energy-rich molecule that can be used throughout the cell to *power active transport, synthesize polymers -move structures within the cell. -many enzymes require ATP to catalyze reactions within the cell that would otherwise proceed very slowly. -energy is lost as heat -ATP cannot be transported; needs to be produced independently by cells

Answer 113

-energy is released when a phosphate group is removed from ATP in a hydrolysis reaction. -the reverse reaction (which is what happens in cellular respiration) regenerates ATP and requires energy input.

Answer 114

1. ATP can not be stored for later use. 2. ATP can not be transferred from cell to cell. 3. When ATP is used in cells heat energy is released. This heat energy can not be reused and will be lost to the environment.

Answer 115

-ATP is an RNA nucleotide with three phosphates -ribose is attached to the nitrogenous base adenine and to the chain of three phosphates. -ATP is made unstable by the three adjacent negative charges in the phosphates, which "want" to get away from each other. -energy is released when one of these bonds is broken in a hydrolysis reaction.

Answer 116

-can act as a backup when cellular oxygen is depleted. e.g. when muscle cells use up oxygen faster than it can be replenished, the cells start to perform anaerobic respiration in order to keep muscles moving. -used when ATP is needed quick, because anaerobic respiration is more rapid than aerobic respiration. -anaerobic metabolism allows microbes to inhabit low-oxygen or oxygen-free environments which allows them to exploit an otherwise empty habitat.

Answer 117

In plants: -glucose is broken down to pyruvate and NADH and ATP are created. -in alcohol fermentation, pyruvate is converted to ethanol. -carbon dioxide is released and NADH is recycled into NAD+. -the reaction nets two molecules of ATP In animals: -glucose is broken down to pyruvate and NADH and ATP are created. -NADH produced in glycolysis transfers its electrons directly to pyruvate, generating lactate as a byproduct. -in lactic acid fermentation, pyruvate is converted to lactic acid. -NADH is recycled into NAD+. -the reaction nets two molecules of ATP.

Answer 118

Anaerobic respiration produces a net of 2 ATPs per molecule of glucose. Aerobic respiration produces up to 38 ATPs per molecule of glucose.

Answer 119

-bioethanol is a fuel produced by yeast alcohol fermentation of sugarcane or corn in large scale fermentors. -enzymes are used to break down starch and cellulose into glucose and then yeast carry out anaerobic respiration using the glucose; producing ethanol.

Answer 120

-when exercising at high intensity, cell demand will exceed available supplies of 02. -muscle cells will start breaking down glucose anaerobically to supply ATP rapidly for a short period of time. -red blood cells do not have mitochondria, so anaerobic respiration always happens.

Answer 121

A respirometer is any measuring tool used to determine the cellular respiration rate of an organism by measuring the rate use of 02 or production of CO2.

Answer 122

One of the important issues in scientific research is to consider ethics in animal experimentation. Regulations and quidelines govern the use of animals, including:. 1. The purpose of the experiment must have some benefit. 2. Overall use of animals should be minimized. Alternative methods should be used if available. 3. Pain and distress must be minimized

Answer 123

Visible light is the portion of the electromagnetic spectrum that is visible to the human eye.

Answer 124

Biological pigments are protein molecules that selectively absorb certain wavelengths of light while reflecting others.

Answer 125

-the primary pigment is the most important/ predominant pigment in the process of photosynthesis. -the primary pigment found in the chloroplast of photosynthetic cells in plants is Chlorophyll which absorb blue and red wavelengths of light.

Answer 126

-pigments used in addition to chlorophyll a are known as accessory pigments. -different pigments respond to different wavelengths of visible light. -the use of accessory pigments allows a broader range of wavelengths to be absorbed, and thus, more energy to be captured from sunlight. Accessory pigment include: Chlorophyll b - absorbs blue and some yellow- orange light Carotenoids - absorb violet and blue-green light

Answer 127

Photolysis means water splitting. During photosynthesis, light energy is used to split water molecules as represented by the following equation: 2H20 > 4H+ + 4e - + 02 Oxygen (02) is released as a waste product in this process. The H+ and e- continue on in the photosynthesis light reactions.

Answer 128

In photosynthesis, light energy is converted into chemical energy stored in carbohydrate molecules. During the light dependent reactions light energy is used to split water. The 4H+ + 4e- formed as a result of the photolysis are used to fuel the formation of two molecules needed for the next stage of photosynthesis: ATP and the electron carrier NADPH. In the light independent reactions, carbon atoms from CO2 are used to build carbohydrates. This process relies on ATP and NADPH from the light dependent reactions.

Answer 129

Photosynthesis is endothermic because an input of energy is required to carry out the process of converting carbon dioxide and water into carbohydrates. The energy for photosynthesis comes from light.

Answer 130

A limiting factor is a variable of a system that can limit the rate of a reaction. Either the amount of light, temperature or CO2 concentration will limit the rate of photosynthesis. Whichever of the three is furthest from its optimal will be the limiting factor.

Answer 131

Temperature: -enzyme-catalyzed reaction -photosynthesis rate will increase as the temperature is raised until an optimal temperature is reached. -after the optimum, the rate of photosynthesis abruptly declines with further increase of temperature. -the decline is because most enzymes involved in photosynthesis rapidly denature at higher temperatures. Light intensity: -without enough light, a plant cannot perform photosynthesis because light energy is required in the light dependent reactions. -increasing the light intensity will increase the rate of photosynthesis. -at a certain point the photosynthetic rate will plateau. -the leveling off is because all available chlorophyll pigments are being used CO2: -without carbon dioxide, a plant cannot perform photosynthesis because CO2 is required in the light independent reactions. -increasing carbon dioxide concentration will increases the rate of photosynthesis -however, at a certain point the photosynthetic rate will plateau. -the leveling off is because all enzymes used in the reactions are being used

Answer 132

The Great Oxygenation Event is defined as the appearance and rise of oxygen gas (02) in the earth's atmosphere beginning about 2.4 billion years ago. -the oxygen is thought to be a result of photosynthesis by prokaryotes called cyanobacteria. -oxygen bubbled out into the atmosphere Evidences: -Banded Iron Formations are layers found in sedimentary rock. -the hypothesis is that the banded iron layers were formed as the result of oxygen released by photosynthetic cyanobacteria. -the oxygen combined with dissolved iron in Earth's oceans to form insoluble iron oxides. Evidences: -Banded Iron Formations are layers found in sedimentary rock. -the hypothesis is that the banded iron layers were formed as the result of oxygen released by photosynthetic cyanobacteria. -the oxygen combined with dissolved iron in Earth's oceans to form insoluble iron oxides, which precipitated out, forming layers on the ocean floor.

Answer 133

The action spectrum shows is the rate of a photosynthesis plotted against wavelength of light. -it shows that blue and red wavelengths of light are most effectively used for photosynthesis.

Answer 134

An absorption spectrum shows the wavelengths of light absorbed by a pigment. -chlorophyll, the most prevalent pigment used in photosynthesis, has a peak absorption between 400 and 500 nm (blue light) and another (smaller) peak between 600 and 700 nm (red light). -there is no absorption around 600 nm (green light) as most of this light is reflected.

Answer 135

-the peaks in the action spectrum showing the rate of photosynthesis correspond to the peak light energy wavelengths that are able to be absorbed by chlorophyll. -since chlorophyll is most effective at absorbing blue and red light, the rate of photosynthesis is also higher with blue and red light. -differences between the chlorophyll absorption spectrum and the action spectrum are due to absorption by accessory (ie carotene). -chlorophyll does not absorb green light, so the there is less photosynthesis within the green light wavelengths. This is shown as a dip in the action spectrum.

Answer 136

There are a few key methods to calculate the rate of photosynthesis. These include: Measuring the uptake of CO2 -immobilized algae in hydrogen carbonate indicator solution -monitor the CO2 concentration using a CO2 sensor Measuring the production of 02 -counting bubbles formed -measuring water displacement by 02 gas formed -floating leaf disk Measuring the increase in dry mass -harvest plants and record how much mass they have accumulated as a proxy measure for carbohydrate formation

Answer 137

The ratio of the distance moved by a pigment to the distance moved by the solvent is a constant, Rf. Each type of molecule has its own Rf value. Rf = distance traveled by pigment / distance traveled by solvent

Answer 138

Beta carotene is carried the furthest because: -it is highly soluble in the solvent -it forms no hydrogen bonds with the chromatography paper fibers. Xanthophyll contains oxygen and does not travel quite as far with the solvent because: -it is less soluble than beta carotene -forms some hydrogen bonds with the paper. Chlorophylls are bound more tightly to the paper than the other two, so they travel the shortest distance.

Answer 139

The absorption spectrum indicates the wavelengths of light absorbed by each pigment (e.g. chlorophyll) The action spectrum indicates the overall rate of photosynthesis at each wavelength of light

Answer 140

Collagen is made of three different types of polypeptide chains.

Answer 141

Insulin is a protein composed of two different polypeptide chains.

Answer 142

Rhodopsin is found in the rod cells of the retina.

Answer 143

Hemoglobin Rubisco

Answer 144

Energy store that is released through aerobic cell respiration Heat insulator (does not conduct heat well)

Answer 145

more and two but less than 20 amino acids amino acid -> dipeptide -> oligopeptides -> polypeptide

Answer 146

oligossacharide

Answer 147

Globular: round spherical soluble more stable than fibrous protein functional rather than structural irregular sequence Fibrous: sraight and long insoluble less stable structure has repeated, reqular sequence

Answer 148

chlorophyll xantophyll carotenoids phycocyonin

Answer 149

Polymerization in nucleotides is the process of joining nucleotide monomers to form a nucleic acid polymer, essential for DNA and RNA formation. Nucleotides consist of a nitrogenous base, a pentose sugar, and a phosphate group. Enzymes called polymerases catalyze the formation of phosphodiester bonds between the 3'-OH group of the sugar of one nucleotide and the 5'-phosphate group of another, resulting in nucleotide dimers. The carbon atoms involved in the formation of the phosphodiester bond are the 3' carbon of the pentose sugar and the 5' carbon of the phosphate group. Dimers can further polymerize into polynucleotides through the addition of more nucleotides. In DNA, the nitrogenous bases form the genetic code, while in RNA, they can be any of the four bases.