Cell Bio Exam 1 Flashcards


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USF Dr. Daniels
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1

Who is credited with the discovery of [REDACTED]?

The Cell, Robert Hooke or first amino acid sequence of a protein discovered by Frederick Sanger

2

Bacteria have a symbiotic relationship with humans. The microbiome that resides within the intestines performs the following functions except?

Aid in Pathogenesis

3

Intestinal cells, by increasing folds within the [REDACTED](Plasma membrane) create __________ in order to increase surface area for [REDACTED].

Villi, aiding/capturing material in digestion

4

Cell theory describes the properties that all cells have in common. Which of the following is absent from cell theory?

Cell Theory has 3 tenets:
1) Cell = basic unit of life
2) Cells can only arise from pre-existing cells
3) All living organisms are composed of 1+ cell(s)

5

Which of the following is a feature shared by prokaryotic and eukaryotic cells?

Plasma membrane, also ribosomes, identical genetic code, metabolism, ATP synthesis, cytoplasm, photosynthesis, and proteosomes.

6

An individual walks out of the USF library on a bright sunny day without sunscreen. The skin on the person’s arms begins to burn from the UV radiation and the DNA is damaged so the skin cells commit apoptosis and flake off few days later. What feature of the dying cells is occurring?

Cells are responding to stimuli

7

Considering viruses, which of the following could be used to argue that viruses are living things?

  • viruses do not derive directly from other viruses like cells derive from other cells as stated in the cell theory. They can only reproduce when present within a living cell. Viruses aren’t made of cells.

-Protein Sugars + Nucleic acids
- They are however, made of DNA or RNA. (Potential argument)
- Obligate parasites
- No metabolism
- No response to stimuli
- No growth
* Also, many opportunistic/parasitic bacteria display some of these characteristics*

8

Why are cells [Microscopic] in size?

The distance between the cell surface and interior becomes too great for the cell's needs to be met by simple diffusion.

The surface area becomes limiting as a cell increases in size.

9

Which of the following statements is [REDACTED] regarding the tenets of cell theory?

Cell Theory has 3 tenets:
1) Cell = basic unit of life
2) Cells can only arise from pre-existing cells
3) All living organisms are composed of 1+ cell(s)

10

Which of the following is [REDACTED] of all cells?

- If [not true] - All cells do not contain a nucleus , all cells contain organelles
- If [true] - All cells have a plasma membrane, ribosomes, cytoplasm, and DNA

11

Which of the following statements [REDACTED] bacteria from eukaryotic cells?

  • Maybe [differentiate]? Smaller in size, no nucleus, no membrane bound organelles, replicate using binary fission, have a singular circle of DNA, usually only have one copy of genes.

Bacteria do not have independent organelles

12

Which of the following examples best describes the [REDACTED] law of thermodynamics?

1st law- (conservation) energy cannot be created or destroyed only changed
2nd law- (direction) events move towards states of lower energy and greater disorder

13

. _____ is the class of biomolecule that functions primarily as a store of chemical energy and as durable building material for biological construction (e.g. glycogen, cell walls)

Carbohydrates

14

Which of the following is [not] a major category of biomolecule?

Cholesterol

15

In a [redacted] (water molecule) the bond between hydrogen and oxygen is best described as a ___________.

Polar covalent bond

16

How many different [amino acids] are used by the genetic code to make proteins?

20

17

[REDACTED] are extremely reactive and capable of chemically altering many types of molecules, including proteins, nucleic acids, and lipids

  • Radicals
18

Which of the following is a polar uncharged amino acid?

Serine (S, Ser), Threonine (T, Thr), Glutamine (Q, Gln), Asparagine (N, Asn), or Tyrosine (Y, Tyr), Cysteine (C, Cys)

19

The [_____] level of protein organization requires [multiple-independent polypeptide chains] to associate together.

quaternary

20

Which of the following is not true about a reaction that occurs [REDACTED]? (spon/nonspon)

  • [Spontaneously?] - Reactions require *some* input of energy to proceed, negative delta G, proceeds to state of lower energy, exergonic. Releases energy.
    [Nonspontaneously?] - Occurs with energy input, positive delta G, proceeds to state of higher energy, endergonic. Gains energy.

But it’s asking what’s NOT true about these reactions, so switch that for the test

21

As you saw with hemoglobin, amino acid substitutions, which can result from mutations, can have deleterious effects. From the list below, select the amino acid substitution that would be the [REDACTED] harmful to the function and structure of the protein. As a hint compare and contrast the amino acids in each pair.

If you look in the book in Chapter two he uses sickle cell anemia as an example of an amino acid substitution. The amino acid valine was substituted with glutamic acid which created the sickle cell shape in the hemoglobin thus creating the disease of sickle cell anemia. A nonpolar amino acid replaced with an acidic amino acid created a mutation.

“nonpolar valine residue is present where a charged glutamic acid is normally located.” (page 55 in book). So in other words, a normally charged (+/-) amino acid (either glutamic acid , aspartic acid, lysine, arginine, and histidine) is substituted for a nonpolar amino acid

22

Which of the following is not a weak interaction?

  • Weak interactions include Van Der Waals, H-bonding, Salt bridges, H-phobic, electrostatic interactions
    - Strong include: Covalent bonds (such as Disulfide, Peptide?, …)
    • strong bonds include metallic, multiple bonds (double bond, triple bond), covalent bond, or ionic bond

weak bonds include dipole-dipole interactions, van der waal forces, and hydrogen bonding.

23

According to current thought, the molecule that is [REDACTED] “The basic unit of?” life is:

  • The basic unit of life is the cell

there are 4 types of molecules of life: proteins, carbohydrates, lipids, and nucleic acids

24

Which of the following is not true of catalytic sites on enzymes?

  • As catalysts, enzymes can only decelerate the rate at which a favorable chemical reaction proceeds.
    • The binding of a substrate to enzyme at the active site is accomplished by covalent bonds.
    • so are both of these true or ^^^
    • I’m not sure the second fact is true or not. Irreversible inhibitors bond covalently with the active site of enzymes, permanently decreasing activity. Can anyone confirm this?
    • both facts listed are possible NOT TRUE answers ( from class quizzes)
    • Agreed^ Both options are FALSE
    • The only thing enzymes do is lower the activation energy for a reaction, which allows it to speed up the reaction. Enzymes cannot decelerate the rate of a reaction
25

In metabolism, anabolic pathways lead to ______ of more complex compounds from simpler starting materials.

synthesis

26

The conversion of metallic iron [Fe0] to the ferrous state [Fe2+], in which the iron atom loses a pair of electrons, thereby attaining a more positive state is said to be _____.

Oxydized

27

Since each enzyme molecule is only able to catalyze a certain number of reactions in a given amount of time, the velocity of the reaction approaches a maximal rate as the substrate concentration increases. The substrate concentration at which the reaction is at half-maximal velocity is called the [_____] and has the symbol Km

Michaelis constant

28

The further a reaction is kept away from a(n) equilibrium state, the more [______].

capacity it has to do work

29

In the cell, energy from ATP hydrolysis may be used to:

  • Separate charge across a membrane
  • - Concentrate a particular solute within the cell
  • - Drive unfavorable chemical reactions

- Donate a phosphate group to a protein

30

Assuming complete conversion of [REDACTED] of glucose to [REDACTED] of pyruvate through glycolysis, how many ATP are generated by the pathway? (read this question carefully)

  • Dr. Daniel stated in raise your hand: One key to knowing how many ATP are produced is by looking at how many pyruvate are produced. For each mole of pyruvate created, 2 moles of ATP were generated. So for example, each mole of pyruvate generates 2 moles of ATP. So 5 moles of pyruvate would generate 10 moles of ATP
  • Each mole of glucose generates 2 moles of pyruvate and 4 ATP. (2 ATP are consumed in glycolysis, but the question asks for the number of ATP generated, not the net ATP. See p. 113 and Dr. Daniel’s lecture Ch. 3 Part 3.)
31

Which of the following statements best describes how enzymes function?

  • Enzymes are biological catalysts. They are the mediators of metabolism and they are responsible for virtually every reaction that occurs within the cell..without enzymes metabolic processes would proceed so slowly as to be imperceptible
    - Enzymes speed up reactions.
    - Enzymes drive reaction mechanisms through
    DIFFERENT, more thermodynamically favorable reactions to speed them up.
  • They lower the amount of energy needed (Activation Energy) to get the reactant molecules into the transition state.
    • Not completely right, in Dr. Daniel’s ch 3 lecture he says enzymes just make the conditions for a reaction more favorable, there is no reduction of activation energy, just changing the reaction to a more favorable one.
  • Enzymes reroutes the reaction to take a completely different route that requires a lower activation energy for the reaction to occur
32

(A = True / B = False) Catabolic reactions frequently result in the production of ATP and NADH.

TRUE (Actually I believe it’s false, produces NADPH not NADH), I agree that it is false, energy will be released as ATP or NADPH (pg 108)

  • I think it’s true because catabolic just refers to the breakdown. Such as in cellular respiration the reactions produce atp and NADH ??
  • True, the book says that catabolic reactions provide energy for other activities in the cell
  • TRUE. According to Dr. Daniel’s lecture Ch. 3 Part 3, “ATP and NADH are made frequently in catabolic reactions. NADPH is made by some special reactions and is used frequently in anabolic reactions.”
  • True, agree its in the lectures

I agree; TRUE

33

From the information below, determine which reaction proceeds at the fastest rate:

The control reaction proceeds at a faster rate because adding a competitive inhibitor will require a higher concentration of substrate to achieve the same reaction.

the addition of catalysts increases the rate of reaction by lowering the activation energy

34

Was the drug a [Competitive or noncompetitive] inhibitor. (since the question is identifying the inhibitor) [previous question, not stated]

  • Competitive inhibitor: high Km and Vmax is the same.
  • Non-competitive inhibitor: Km the same and Vmax drops.
  • Find KM for each reaction. If the drug is a competitive inhibitor, the experiment with drug added should have a higher KM because it would lower the enzyme’s affinity for the substrate. If the drug is not a competitive inhibitor, its KM would be the same or lower than the control.
35

(A = True / B = False) Under anaerobic conditions, glycolysis can still proceed due to a side reaction. In this case, the released product is lactic acid and the pathway makes NADH. [REDACTED].

  • True, due to fermentation I believe
    • False because the released products are lactic acid and NAD+. NADH is consumed.

False - releases lactic acid and consumes the NADH.

36

In animal cells, which of the following is not a function of the plasma membrane?

Functions are: Substrate transport, scaffold for biochemical reactions, compartmentalization, selectively permeable barrier response to stimuli, intercellular communication, energy transduction

37

Protein conduits in the plasma membrane that are permeable to specific charged atoms are known as [_____].

ion channels

38

(Human Perspective) Which of the following is not true of the Cystic Fibrosis?

CFTR deficiency leads to an increase of fluid that bathes the epithelial cells of the airways.

39

The following are all amphipathic except:

Triglycerides

40

Without __________, plasma membranes would be too fluid, not firm enough, and too permeable to some molecules.

Cholesterol

41

What prevents digestive enzymes from digesting anything and everything in the cell?

Compartmentalization

42

What type of sphingolipid is an amino-alcohol with a long hydrocarbon chain to which is attached a [ceramide, sphinomyelin, cerebroside, ganglioside]?

Ceramide; attached fatty acid
- Sphingomyelin; attached phosphorylcholine
- Cerebroside; attached simple sugar
- Ganglioside; attached small cluster of sugars that includes sialic acid
- Glycolipid; attached carbohydrate

43

Consider a person that has the enzyme that [Adds N-acetylgalactosamine, adds galactose, neither]. What is/are the possible blood types?

  • Adds N-acetylgalactosamine: Blood type A (or AB if the question doesn’t specify it is only N-acetylgalactosamine)
  • - Adds galactose: Blood type B (or AB if the question doesn’t specify it is only galactose)
  • - A and B type has both of the above enzymes

- O has neither enzyme

44

You’ve found a membrane protein that is [within, outside, outside covalently bonded to lipid] in the membrane. How would you classify this protein?

Integral proteins: [within] the membrane
Peripheral proteins: [outside] of the membrane (noncovalently bonded).

Lipid Anchored proteins: [outside] membrane, covalently bonded to lipid in bilayer

45

Consider a cell with [REDACTED] sodium atoms on the extracellular side and [REDACTED] potassium atoms on the cytosolic side of the plasma membrane. After one run of a Na+ / K+ active pump, [REDACTED]?

  • The ratio of sodium and potassium pumped for each ATP is 3:2, 3 Na out and 2 K in

Because of this pumping ratio, the Na+/K+ ATPase pump is electrogenic

46

Movement of what ion, with its gradient, allows intestinal cells to move glucose against its gradient from the lumen of the intestine into the cytosol of the cell via a symport?

Sodium Ion (Na+)

47

How is it that, unlike polysaccharides such as starch and glycogen, the oligosaccharides on the surface of the plasma membrane can be involved in specific interactions?

  • Oligosaccharides can be composed of different sugar unit combinations and can vary structurally (pg 129)
  • Oligosaccharides at the cell surface contain a variety of different sugar subunits (glycosylation) whose arrangement within the complex is highly defined.

Oligosaccharides play a role in mediating the interactions of the cell with its environment and sorting the membrane proteins to different cellular compartments

48

Suppose you were culturing a population of bacteria at [REDACTED] degrees Celsius and then [REDACTED] the temperature of the culture to [REDACTED] degrees Celsius. What effect do you think this might have on the fatty acid composition of the membrane?

  • If this is talking about the arrangement of the fatty acids within the membrane, the higher temperature causes more fluidity (more room) within the membrane. Colder temperatures will condense and stiffen the membrane.
    - If the temperature rises: It would be expected to cause the level of saturation of the fatty acids of the membrane to increase (the number of polyunsaturated fatty acids to decrease), which would raise the transition temperature of the lipid bilayer. The activity of membrane desaturases would be expected to decrease.

If the temperature is raised from 15 degree celsius to 37 degree celsius - the membrane fluidity is increased. There is an increase in the number of unsaturated fatty acids and the chains are shorter

As the temperature of growth is lowered (ex. from 37 degree celsius to 15 degree celsius), the proportion of unsaturated fatty acids (fatty acids w/ double bonds) increases. Thus, increasing fluidity. When the temperature of growth is raised, (Ex. from 15 degrees celsius to 37 degrees celsius) the proportion of saturated fatty (fatty acids w/ no double bonds) increases. Thus, decreasing fluidity

49

From the answers below select the one that contains the following amino acids (note the order does not matter):

Basic (positive):
◦ Histidine (His, H)
◦ Argine (Arg, R)
◦ Lysine (Lys, K)