Exam 2 Flashcards

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1
Q

At very high temperatures (e.g., above 100°C), enzymes cease to perform their function. This happens because the high temperature

A. causes the substrate to move so fast the enzyme cannot bind to it
B. denatures the cofactor
C. converts the enzyme into product molecules
D. destroys the shape of the enzyme

A

D. destroys the shape of the enzyme

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2
Q

Which of the following statements is FALSE?

A. The lock and key model refers to the specificity of an enzyme for its substrate
B. Cofactors bind to substrate molecules and prevent enzymatic reactions from occurring
C. Temperature and pH have significant effects on the activity of an enzyme
D. Enzymes are proteins that are synthesized by ribosomes

A

B. Cofactors bind to substrate molecules and prevent enzymatic reactions from occurring

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3
Q

In the “lock and key model” of enzyme activity, which molecule is described as the “key”. The enzyme, substrate or product.

A. Enzyme
B. Substrate
C. Cofactor
D. Inhibitor

A

B. Substrate

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4
Q

Lactase is an enzyme that converts lactose to glucose and galactose. A scientist measured the time it took lactase to convert the lactose in different pH environments. His results are represented in the following table.

PH. - Avg. time for conversion (secs)
4-      105
5-      95
6-      82
7-      89
8-      110

What is the optimal pH for the lactase reaction?

A

6

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5
Q

What organelle found in cells produces or synthesizes enzymes?

A

Ribosome

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6
Q

Cyclooxygenase (COX) promotes the conversion of Arachidonic acid to Prostaglandins. Prostaglandins is a hormone that functions in activating pain signals and inducing inflammation. Pain killers such as Aspirin work by inhibiting the activity of Cyclooxygenase.

  1. Which of the bolded words is the molecule with an active site?
  2. Which of the bolded words is the substrate?
A
  1. Cyclooxygenase (COX)

2. Arachidonic acid

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7
Q

When your cells produce carbon dioxide (CO2) as a waste product, it is immediately converted to carbonic acid (H2CO3) in the following reaction:

CO2 + carbonic anhydrase + zinc —> H2CO3 + carbonic anhydrase + zinc

  1. Which of the molecules is the enzyme?
  2. What is the cofactor in this reaction?
A
  1. Carbonic anhydrase

2. zinc

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8
Q

An enzyme is an example of which macromolecule?

A

protein

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9
Q

What is the function of a catalyst? Are enzymes catalysts?

A

To speed up reaction, yes

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10
Q

Is the substrate/reactant of the left or right side of an equation? Product?

A

substrate- left

product- right

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11
Q

How do enzymes affect the activation energy needed for a chemical reaction?

A

enzymes reduce activation energy which causes the reaction requires less energy to get started. If an enzyme is present, the AE is reduced significantly and it will be faster bc requires less energy.

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12
Q

Will a chemical reaction occur when an enzyme is not present? What is the difference in activation energy when an enzyme is not present?

A

Yes, Chemical reactions occur too slowly without enzymes so you would already be dead.

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13
Q

What name is given to the region or site on an enzyme where a substrate binds?

A

Active site

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14
Q

Name and describe the 3 properties of enzymes.

A
  1. Biological catalyst: speeding up chemical reactions. That is, they are catalytic
  2. Recyclable: They do not become a part of the chemical reaction. They catalyze a chemical reaction and once the products are formed and released, they move on unchanged to catalyze another reaction
  3. Highly specific: for the substrates they bind. Only a substrate with the exact shape as the shape of the binding region of the enzyme will bind to that enzyme
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15
Q

What happens to the activation energy once the substrate binds to an enzyme at the binding region?

A

The activation energy is then reduced and the chemical reaction can occur quickly.

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16
Q

What are examples of cofactors? Do they bind to enzymes or substrates? How do they help the molecules to which they bind?

A

Cofactors: a mineral/vitamin (iron, mg, zinc) that is necessary to maintain the 3d shape of an enzyme.
They bind to enzymes by filling in empty space the substrate can’t fill so it’s a perfect fit.
They are specific accessory molecules required for enzymes to function.

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17
Q

3 Factors that affect enzyme function?

A

Temp, pH, Inhibitors

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18
Q

Do warm or cold temp. cause peak activity of enzymes?

A

warm

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19
Q

the higher temp, the ___ reaction rate unit a certain point where the enzyme becomes ____.

A

faster, denatured

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20
Q

What are irreversible inhibitors? Give examples.

A

Inhibitors that bind to enzymes at the binding region and cause permanent damage to enzyme shape which leads to loss of enzyme function.

Heavy metal ions (mercury and lead), nerve gas poisons (cyanide), some insecticides

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21
Q

what are reversible inhibitors? what are the two types?

A

Reversible inhibitors cause temporary loss.

Competitive inhibitors: inhibitor and substrate both bind to the active site of the enzyme. Binding of an inhibitor prevents substrate binding, thereby inhibiting enzyme activity. They compete for active site bc they have the same site

Noncompetitive inhibitors: Inhibitor and substrate bind to different sites. There is an active site and inhibitor site so they aren’t competing for the active site. When it binds, it changes the shape of the enzyme and they mess up the active site.

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22
Q

what is a polypeptide bond?

A

individual covalent bonds that link amino acids in polypeptide chains

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23
Q

What is the ultimate source of energy?

A

Solar energy/ energy from sun

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24
Q

What are autotrophs? What do they do?

A

they are plants and other photosynthetic organisms. They capture solar energy (form sun) in the form of light energy which is converted into chemical energy.

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25
Q

Where is chemical energy stored? Then what happens?

A

within the bonds of molecules. The chemical energy is used to power chemical reactions

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26
Q

light energy is converted into ____, which is chemical energy.

A

glucose

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27
Q

The ONLY type of light autotrophs can use for energy during photosynthesis is ____, which is seen as____.

A

visible light, colors

28
Q

Light travels to the earth surface as particles called?

A

Photons

29
Q

Light behaves as ____.

A

waves

30
Q

the measure of the peak of one wave to the peak of another is called ____.

A

wavelength

31
Q

light energies are measured in _____.

A

wavelengths

32
Q

What is the inverse relationship between wavelength and energy?

A

shorter wavelength, greater the energy

or taller wavelength, lower energy

33
Q

list the 3 fates of light

A

absorption: light energy retained by pigment molecules.
reflection: light energy is not retained so it bounces back (colors we can see)
transmission: light absorption that passes through

34
Q

which of the 3 fates of light can ONLY BE USED for photosynthesis

A

absorption

35
Q

What wavelength generates least amount of photosynthesis? the most?

A

green, red and blue

36
Q

What is the primary photosynthetic pigment?

A

Chlorophyll a

37
Q

what pigment absorbs wavelengths of visible light that the primary photosynthetic pigment cannot then passes these light energies to the primary pigment?

A

accessory pigments

38
Q

which of the following statements is TRUE?

a. plants use reflected light energy to perform photosynthesis
b. chlorophyll a is the primary photosynthetic pigment
c. radio waves have longer wavelengths and more energy than x-rays, which have shorter wavelengths
d. A & C

A

b. chlorophyll a is the primary photosynthetic pigment

39
Q

where does the light (photo) reaction of photosynthesis occur? (AEROBIC)

A

thylakoid membrane (look like hot pockets or coins)

40
Q

what is a stack of thylakoid called? What do they do?

A

granum, increase SA within the chloroplast

41
Q

where does dark (synthesis) reaction occur? (AEROBIC)

A

stroma (fluid)

42
Q

what are the products of light reaction in photosynthesis?

products of dark?

A

ATP, oxygen

glucose

43
Q

which gas is generated in light reaction?

A

oxygen

44
Q

Electrons of chlorophyll a are lost when they become energized. How are these electrons replaced?

A

by split water molecules release electrons that replace electrons lost by excited chlorophyll molecules.

45
Q

The function of cellular respiration is to __________
A. Extract CO2 from the atmosphere
B. Produce carbohydrates
C. Extract usable energy from glucose
D. Synthesize macromolecules from monomer

A

C. Extract usable energy from glucose

46
Q
Which energy-rich molecule produced by cellular respiration directly powers cell work?
A. Glucose
B. ATP
C. Water
D. Oxygen
A

B. ATP

47
Q
In which stage of aerobic respiration is carbon dioxide produced?   
A. Electron transport
B. Glycolysis 
C. The citric acid cycle 
D. A, B, and C
A

C. The citric acid cycle

48
Q
One important end product of cellular respiration is \_\_\_\_\_. 
A. Glucose
B. Hydrogen gas
C. Water
D. Oxygen
A

C. Water

49
Q

Which of the following puts the stages of aerobic respiration in the correct order?
A. Electron transport chain> citric acid cycle> glycolysis
B. Citric acid cycle> glycolysis> electron transport chain
C. Citric acid cycle> electron transport chain> glycolysis
D. Glycolysis> citric acid cycle> electron transport chain
E. Glycolysis> electron transport chain> citric acid cycle

A

D. Glycolysis> citric acid cycle> electron transport chain

50
Q
Which stage of cellular respiration occurs in the cytoplasm of a eukaryotic cell? 
A. Electron Transport Chain
B. Glycolysis
C. Citric Acid Cycle
D. A, B, and C
A

B. Glycolysis

51
Q
Which of the following stage(s) of aerobic respiration occur in the mitochondria?  
A. Glycolysis
B. The citric acid cycle
C. Electron transport chain
D. B and C but not A
E. A, B, and C
A

D. B and C but not A

52
Q
Which of the following stages strips electrons from bonds between carbon atoms?  
A. Glycolysis
B. The citric acid cycle
C. Electron transport chain
D. B and C but not A
E. A, B, and C
A

B. The citric acid cycle

53
Q
Oxygen is most important in which of the following stage(s) of aerobic respiration?  
A. Glycolysis
B. The citric acid cycle
C. Electron transport chain
D. A and C but not B
E. None of the above
A

C. Electron transport chain

54
Q
What by-product of respiration is required for photosynthesis? 
A. Glucose
B. Nitrates
C. Oxygen
D. Carbon dioxide
E. Phosphates
A

D. Carbon dioxide

55
Q

Molecules that come from the food we eat provide energy for the amazing work that goes on inside of our cells. This energy, stored inside of our food, is a form of _____.
A. Kinetic energy called heat
B. Electrical energy called heat
C. Potential energy called chemical energy
D. Potential energy called activation energy

A

C. Potential energy called chemical energy

56
Q
Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing \_\_\_\_\_\_.
A. Kinetic energy into potential energy
B. Chemical energy into potential energy
C. Chemical energy into kinetic energy
D. Kinetic energy into chemical energy
A

C. Chemical energy into kinetic energy

57
Q

Which of the following benefit of the endothermic strategy?
A. allows organisms to have a smaller body size
B. allows an organism to maximize activity over a wider range of env. temps
C. allows an organism to take advantage of unpredictable resource availability
D. allows an organism to have lower energy requirements

A

B. allows an organism to maximize activity over a wider range of environmental temperatures

58
Q

How do you calculate SA:V ratio? Use a cube for example.

A
V= LxWxH
2x2x2=8cm^3
SA= (LxW) x # of sides
2x2 (area) x 6 =24cm^3
ratio is 24:8= 3:1
59
Q

what is formula for weight-specific consumption? List units.

A
Oxygen consumption (ml/hr)/ Body weight (g)
Units are expressed in ml/(g-hr)
60
Q

Do endotherms or ectotherms maintain body temp independent of env temp?

A

endotherms

61
Q

the SA of a cell is in the ___.

A

plasma membrane

62
Q

what are the 4 fates of glucose in animal cells?

A
  1. Metabolized completely by aerobic respiration
  2. Fermented anaerobically to lactate or ethanol
  3. Synthesized as glycogen (short term storage)
  4. Converted to Fat/adipose cells or triglyceride (long term storage)
63
Q

pyruvate is a ___ molecule.

A

sugar

64
Q

as size increases, SA:V ratio _____.

A

decreases

65
Q

Give examples of renewable and nonrenewable forms of energy.

A

Renewable: natural energy sources: heat and light from sun, water, wind
Non-renewable: energy sources that don’t regenerate: natural gas, coal, fossil fuels, nuclear

66
Q

what is the difference between potential, chemical, and kinetic energy?

A

chemical: energy stored between bonds. Any molecules is chemical molecules. Glucose, ATP, pyruvate, any molecules that is held together by covalent bonds
potential: stored energy. Glucose is type of this, so is ATP. Not until break bonds of ATP that is released that we actually do work
kinetic: blinking, membrane transport, energy that is emotion

67
Q

what type of molecule is ATP?

A

nucleotide