Bio 181 Unit Test 4

Question 1

What is a phosphatase?

Answer 1

An enzyme that REMOVES a phosphate group from a protein

Question 2

Do eukaryotes have telomeres?

Answer 2

YES

Question 3

Do prokaryotes have telomeres?

Answer 3

NOOOOO

Question 4

What would happen if DNA ligase did not function during DNA replication?

Answer 4

The okazaki fragments in the lagging strand would not be joined together, there would be gaps in the DNA

Question 5

What organelles do prokaryotes have?

Answer 5

Only ribosomes and chromosomes

Question 6

Which direction (from 3’ to 5’ on the leading strand) does DNA synthesis go?

Answer 6

To the right (towards the 5’ end)

Question 7

Which direction (from 5’ to 3’ on the lagging strand) does DNA synthesis go?

Answer 7

To the left (towards the 3’ end)

Question 8

If one fully labeled and one fully UNlabeled chromosomes are used for DNA replication, what will the new chromosome look like after ONE round of DNA replication?

Answer 8

Fully half-labeled

Question 9

Describe an exergonic reaction

Answer 9

Exergonic can initiate a reaction without being coupled (spontaneous), and the curve looks like a hill with a straight top (and has negative delta g/releases free energy)

Question 10

Describe an endergonic reaction

Answer 10

Must be coupled to another reaction, has positive delta g, and has high activation energy (the curve looks like a hill with a bump at the top)

Question 11

What amino acid group would most likely interact with a positively charged part of a substrate WITHIN an enzyme’s ACTIVE site

Answer 11

Aspartic acid (it’s an acid)

Question 12

What is competetive inhibition?

Answer 12

Where a molecule that is structurally/chemically similar to the enzyme’s substrate binds to the ACTIVE site and prevents substrate binding

Question 13

What is allosteric inhibition?

Answer 13

Where a molecule binds to the enzyme at an ALLOSTERIC binding site and changes the shape of the site which prevents substrate binding and catalyzes the reaction

Question 14

What is post-translational modification?

Answer 14

Where some proteins are activated or inactivated by chemical modification

Question 15

What is the difference between the allosteric binding site and an active site?

Answer 15

Allosteric: regulatory site on the protein that can affect its activity (turning the enzyme “on or off”)
Active: where the substrate binds and chemical reactions occur

Question 16

What is phosphorylation?

Answer 16

The process where a phosphate group is added to a molecule

Question 17

What is ATP hydrolysis?

Answer 17

A reaction where water breaks the bonds in ATP molecules to release energy and phosphate groups (makes ADP)

Question 18

How is ATP synthesized in cells?

Answer 18

By phosphorylating ADP

Question 19

Where is ATP ALWAYS synthesized?

Answer 19

Mitochondrial matrix

Question 20

Where does glycolysis occur?

Answer 20

In the cytoplasm

Question 21

Where does the citric acid cycle occur?

Answer 21

Eukaryotes: the mitochondrial matrix
Prokaryotes: the cytoplasm

Question 22

What cellular processes synthesize ATP?

Answer 22

Cellular respiration (glycolysis: 2 ATP, citric acid cycle: 2 ATP, and electron transport chain/oxidative phosphorylation: 34 ATP)

Question 23

What are the reactants of the calvin cycle in photosynthesis?

Answer 23

Carbon dioxide, ATP, and NADPH

Question 24

What are the products of the calvin cycle in photosynthesis?

Answer 24

G3P, ADP, and NADP+

Question 25

What is the reactant of glycolysis?

Answer 25

Glucose

Question 26

What are the products of glycolysis?

Answer 26

Two pyruvate, two ATP, and two NADH

Question 27

What is the reactant of the citric acid cycle?

Answer 27

Acetyl-CoA (from glucose and made by the oxidation of pyruvate)

Question 28

What are the products of the citric acid cycle?

Answer 28

carbon dioxide, NADH, FADH2, and 2 ATP

Question 29

What is photosystem II?

Answer 29

First light reaction to occur, found in the thylakoid membrane of chloroplasts, and it captures light energy and uses it to oxidize water molecules (releases oxygen as a byproduct and transfers electrons to the ETC)

Question 30

What are light reactions in photosynthesis?

Answer 30

Where sunlight catalyzes the splitting of water into seperate hydrogen and oxygen atoms (oxygen is released)

Question 31

What is photosystem I?

Answer 31

The second light reaction to occur, also occurs in the thylakoid membrane of chloroplasts, and it is a protein complex within a plant cell that uses the light energy captured from photosystem II to transfer electrons across a membrane

Question 32

What is the energy captured by photosystem II converted into?

Answer 32

The light energy from the sun is converted into potential energy in a H+ gradient

Question 33

What are the reactants of PSI?

Answer 33

electrons from the ETC and light energy

Question 34

What is the product of PSI?

Answer 34

NADPH

Question 35

What are the reactants of PSII?

Answer 35

Water and sunlight

Question 36

What are the products of PSII?

Answer 36

Oxygen, hydrogen ions, and electrons

Question 37

If a cell currently contains mRNA and does not express it, how could the mRNA be expressed?

Answer 37

If the translation of the mRNA is increased

Question 38

If a reporter plasmid containing a regulatory sequence with a gene is inserted into a cell, what will the cell express?

Answer 38

The gene will be expressed from the plasmid when the cell usually expresses the regulatory sequence

Question 39

What membrane transport proteins move ions or molecules up their cell gradient?

Answer 39

pumps

Question 40

What membrane transport proteins move ions or molecules down their cell gradient?

Answer 40

carrier proteins and channels

Question 41

Where are membrane proteins built in a cell?

Answer 41

In the rough ER (the ER with ribosomes)

Question 42

What processes are carried out by RNA polymerase?

Answer 42

transcription (initiation, elongation, and termination)

Question 43

What processes are carried out by DNA polymerase?

Answer 43

DNA replication

Question 44

What polymerase does translation use

Answer 44

Neither, it uses mRNA, ribosomes, and tRNA

Question 45

If a person has the blood genotype AB, what letters are on each chromatid BEFORE mitosis?

Answer 45

Chromosome one: A A Chromosome two: B B

Question 46

If two different cell types are treated with the same signaling molecule and only one responds, why doesn't the other molecule respond?

Answer 46

The other molecule lacks the signaling receptor protein so it cannot respond

Question 47

Where are g-coupled protein receptors made?

Answer 47

The rough ER (they are proteins)

Question 48

Where are glycoproteins made?

Answer 48

The rough ER and then it is transported the golgi apparatus to add the final touches

Question 49

Where are proteins phosphorylated (sugar group is attached to the protein) in a cell?

Answer 49

the golgi apparatus

Question 50

What do the letter alleles (Ff, GG, aa) represent?

Answer 50

DNA sequences (they are alleles of genes!)

Question 51

How does an enzyme drastically increase the rate of the reaction it catalyzes?

Answer 51

It stabilizes the transition state, which then lowers activation energy and increases reaction rate

Question 52

In the calvin cycle, _______ from the light reactions donates electrons to reduce sugar molecules, and ________ from the light reactions donates a phosphate group to phosphorylate sugar molecules.

Answer 52

NADPH; ATP

Question 53

What cell cycle checkpoint are genes coding for DNA replication proteins regulated

Answer 53

The G1 checkpoint to the S checkpoint

Question 54

What are the stages in the cell cycle?

Answer 54

G1, S, G2, and M

Question 55

What does G1 stage do

Answer 55

cell growth, replication of organelles, preparation for DNA synthesis

Question 56

What does G2 stage do

Answer 56

cell growth, preparation for mitosis and cytokinesis

Question 57

What does s stage do

Answer 57

DNA synthesis

Question 58

What does M checkpoint do

Answer 58

cell division

Question 59

Where is the DNA damage checkpoint? (is all DNA undamaged?)

Answer 59

In between G1 phase and S phase

Question 59

Where does the cell cycle check for external growth signals?

Answer 59

Early G1 checkpoint

Question 60

Where is the DNA replication checkpoint? (is all DNA replicated and undamaged?)

Answer 60

At the end of G2 and before the M phase

Question 61

Where is the spindle assembly checkpoint? (are all chromosomes attached to a spindle fiber?)

Answer 61

Before M phase and after DNA replication checkpoint

Question 62

After receptor activation in a signal pathway, what happens?

Answer 62

Signal transduction

Question 63

What is the enzyme responsible for unwinding the double helix is

Answer 63

helicase

Question 64

Why do eukaryotic chromosomes have telomeres?

Answer 64

to ensure the entire chromosome is copied during replication

Question 65

What role do cyclins play in the regulation of the cell cycle?

Answer 65

They activate cyclin-dependent kinases (CDKs)

Question 65

Why is ATP the "energy currency" of the cell?

Answer 65

ATP directly transfers energy to cellular processes by coupling reactions

Question 66

How does an enzyme increase the rate of a biochemical reaction?

Answer 66

By lowering the activation energy

Question 67

What is the final electron acceptor in the citric acid cycle?

Answer 67

Oxygen

Question 68

What would happen if oxygen were unavailable during cellular respiration?

Answer 68

ATP production through oxidative phosphorylation would stop

Question 69

What happens to the energy from electrons as they pass through the ETC?

Answer 69

It pumps protons across a membrane, creating a gradient

Question 70

What is the purpose of light-dependent reactions in phostosynthesis?

Answer 70

To produce ATP and NADPh for the calvin cycle

Question 71

In the calvin cycle, the enzyme rubisco catalyzes a reaction that

Answer 71

fixes carbon dioxide into an organic molecule

Question 71

Which structure in the chloroplast is responsible for capturing light energy

Answer 71

Thylakoid membrane

Question 72

How does photosynthesis relate to cellular respiration

Answer 72

photosynthesis stores energy in glucose while respiration releases it

Question 73

If a mutation blocks ATP synthase activity, what process is directly affected?

Answer 73

chemiosmosis

Question 74

What would happen if telomerase activity increased?

Answer 74

Telomeres will shorten more quickly with each cell division

Question 75

What is an example of an endergonic reaction in cells?

Answer 75

Formation of glucose during photosynthesis (building, forming things are all endergonic)

Question 76

Signal amplification in a signalling pathway is primarily achieved by

Answer 76

Enzymatic cascades that produce many second messenger molecules

Question 77

Which enzyme prevents the over-winding of DNA ahead of the replication fork?

Answer 77

Topoisomerase

Question 78

What is the primary function of substrate-level phosphorylation in cellular respiration?

Answer 78

To produce ATP directly during glycolysis and the citric acid cycle

Question 79

During oxidative phosphorylation, ATP is produced when:

Answer 79

Protons flow through ATP synthase back into the mitochondrial matrix

Question 80

What would happen if a plant could not perform the calvin cycle?

Answer 80

The plant could not fix carbon dioxide into organic molecules (like H+)

Question 81

What is similar between photosynthesis and cellular respiration?

Answer 81

Both involve the formation of ATP via chemiosmosis

Question 82

What is chemiosmosis?

Answer 82

The movement of hydrogen ions across the membrane (from high concentration to low concentration/down the gradient) via ATP synthase