Biology: Molecular & Cell

Question 1

Competitive Inhibitor

Answer 1

Bind at the active site. Can be overcome by high [S]. Vmax does not change. Km is increased.

Question 2

Non-Competitive Inhibitor

Answer 2

Bind allosterically. Vmax is diminishes Vmax. Does not change Km.

Question 3

4 Stages of oxidizing Glucose

Answer 3

Glycolysis -> Pyruvate Dehydrogenase Complex -> Krebs Cycle -> Electron Transport / Oxidative Phosphorylation

Question 4

Surplus of ATP equivalents produced in each stage of glucose oxidation

Answer 4

Glycolysis(5-euk; 7-pro) ; PDC(5); Krebs(20)

Question 5

Glycogenesis

Answer 5

Breaks down the glucose polymer glycogen. Response to glucagon levels. Has effect of releasing Glucose into the bloodstream.

Question 6

Gluconeogensis

Answer 6

Converts non-carbohydrate precursor molecules into oxaloacetate -> Glucose. Occurs primarily in the liver and is a response usually to no dietary source of glucose or depletion of glucose levels in the liver.

Question 7

Beta-Oxidation

Answer 7

The breakdown of fatty acids in the hepatocyte mitochondria. Works by removing 2 carbons per -round and producing acetyl-CoA. Ends up generating (1) NADH and (1) FADH2.

Question 8

The 3 Components of DNA

Answer 8

DeoxyRibose (2’ Hydroxyl group is missing); Aromatic Bases; Phosphate group (joined to the ribose ring at the 5’ Hydroxyl group)

Question 9

The 2 Purines

Answer 9

Adenine & Guanine

Question 10

The 2 Pyrimidines

Answer 10

Cytosine & Thymine

Question 11

Nucleoside

Answer 11

A purine that has the purine/pyrimidine attached at the 1’ carbon via B-N-Glycosydic Linkage

Question 12

Process of Nucleotide Polymerization

Answer 12

1) 3’ OH on sugar attacks the alpha-phosphate of the incoming nucleotide kicking out a pyrophosphate

Question 13

Polymerization of DNA occurs in what direction?

Answer 13

5’ –> 3’

Question 14

The template strand in DNA polymerization is read in what direction?

Answer 14

3’–>5’

Question 15

DNA Pol Requires what 2 things?

Answer 15

Primer & a Template

Question 16

What are the 3 roles of the Prokaryotic DNA Polymerases?

Answer 16

(I) removes & replaces the primer & has 3’–>5’ Exonuclease activity. (II) Unknown role. (III) Main replication polymerase and has 5’–>3’ Exonuclease activity

Question 17

How are nucleotides in the DNA chain linked?

Answer 17

Covalently via phosphodiester bonds between the 3’ Hydroxy group of one deoxyribose and the 5’ Phosphate group of the next deoxyribose.

Question 18

How many hydrogen bonds do AT & GC have?

Answer 18

GC= 3; AT=2

Question 19

Are interactions between bases in DNA hydrophobic or hydrophilic?

Answer 19

Hydrophobic, the also help to stabilize the double helix of the DNA

Question 20

Role of DNA Gyrase

Answer 20

Uses ATP to twist the DNA molecule resulting in the formation of Supercoils

Question 21

Histones

Answer 21

These basic, globular proteins are what the Eukaryotic DNA is wrapped around for packaging. astrand of 8 Histones with DNA wrapped around them is called a nucleosome.

Question 22

The process of reading the DNA and writing the information as RNA is called?

Answer 22

Transcription

Question 23

The reading of the RNA is termed what? Where does it occur?

Answer 23

Translation, occurs in the cytoplasm

Question 24

DNA–> Protein, basic process description

Answer 24

DNA is copied into the mRNA, mRNA then travels to the cytoplasm and encounters the ribosome where polypeptides are produced according to the mRNA’s code.

Question 25

What are the 3 stop codons?

Answer 25

UAA ; UAG; UGA

Question 26

Stop Codons are what type of codon?

Answer 26

Nonsense

Question 27

3 Types of Mutations

Answer 27

Point Mutation; Insertion Mutation; Deletion Mutation

Question 28

Point Mutation

Answer 28

Single base-pair substitutions. Can be transitions or transversions. 3 subtypes: Missense (cause a different amino acid to be produced). Nonsense (replaces a regular codon with a stop codon). Silent (change a codon into a new codon for the same AA).

Question 29

2 Types of Frameshift Mutations

Answer 29

Insertion & Deletion

Question 30

Helicase

Answer 30

Unwinds the DNA by using the energy from ATP, starts at the Origin of Replication

Question 31

Topoisomerase

Answer 31

These function to prevent breakage of the DNA during unwinding by Helicase. Opposite of DNA Gyrase’s function.

Question 32

Single Stranded Binding Proteins

Answer 32

Protect unpackaged DNA and prevents the strands from coming back together.

Question 33

Prokaryotic mRNA is mono or polycistronic? Eurkaryotic?

Answer 33

Prokaryotic is Polycistronic, whereas Eukaryotic mRNA is MonoCistronic

Question 34

The sequence of nucleotides that begins the process of transcription by activating RNA polymerization is ?

Answer 34

The Promoter

Question 35

The point where RNA polymerization actually starts is called?

Answer 35

The Start Site

Question 36

The principle site of gene regulation in pro and eukaryotes

Answer 36

Transcription

Question 37

The strand which is actually transcribed is

Answer 37

template strand or the antisense strand

Question 38

Downstream vs Upstream

Answer 38

Downstream = towards the 3’ coding end of the transcript. Upstream = towards the 5’ coding end of the transcript.

Question 39

The 5 subunits of the prokaryotic RNA polymerase

Answer 39

(2) alpha, B, B’, Omega