Leys

Question 1

Cells acquire nucleotides through two processes

Answer 1

De novo synthesis

Salvage pathways

Question 2

De novo synthesis of _____ results in the synthesis of ____ that can be converted into ______ & ______

Answer 2

Purines
Inosine
Adenosine
Guanosine

Question 3

Atoms in a newly synthesized purine are derived from several sources including

Answer 3

Aspartate
Glutamine
Glycine
Methyl groups supplied by folic acid and CO2

Question 4

____ and ___ regulate de novo synthesis of purines at ___ point(s) in the pathway

Answer 4

ADP
GDP
multiple

Question 5

____ and ____ can be recycled through the salvage pathway with ______

Answer 5

Hypoxanthine
Guanine
Hypoxanthine guanine phosphoribosyl transferase (HGPRT)

Question 6

_____ catalyzes a hydroxylase type reaction leading to the formation of ____ that can be excreted

Answer 6

Xanthine oxidase

uric acid

Question 7

Excess or low levels of secretion of uric acid is the cause of ____

Answer 7

gout

Question 8

Crystallization of _____ in the joints leads to a localized inflammatory response

Answer 8

Sodium urate

Question 9

_____, a ____ analog, is used to treat gout. It inhibits _____ preventing the formation of uric acid.

Answer 9

Allopurinol
Purine
Xanthine oxidase

Question 10

A ____ deficiency causes _____ syndrome that results in severe retardation, crippling gouty arthritis and self mutilation

Answer 10

HGPRT

Lesch-Nyhan

Question 11

Lesch-Nyhan occurs only in ____ because the HGPRT gene is located on the ________

Answer 11

Males

X chromosome

Question 12

The breakdown of purines can replenish _____ intermediates through the production of ______

Answer 12

TCA cycle

Fumarate

Question 13

The atoms in a pyrimidine ring are derived from

Answer 13

Aspartate and Carbamoyl phosphate

Question 14

The first 3 enzymes in pyrimidine synthesis are located on this protein

Answer 14

CAD protein

Question 15

The pyrimidines _ and _ can be interconverted

Answer 15

U and C

Question 16

____ is converted to ___ by _____, an enzyme requiring the transfer of a methyl group from tetrahydrofolate

Answer 16

dUMP
TMP
Thymidylate synthase

Question 17

Inhibitors of ____ production are used as therapeutic agents for treating cancer and bacterial infections

Answer 17

tetrahydrofolate

Question 18

___ substituted pyrimidine analogs that inhibit ____ are used as anticancer agents

Answer 18

Fluro

Thymidylate synthase

Question 19

_____ converts ribonucleotides to deoxyribonucleotides

Answer 19

Ribonucleotide reductase

Question 20

Base-pairing in DNA is ___ and ____. In RNA it’s ____ and ____

Answer 20

AT and GC

AU and GC

Question 21

Why would homologous regions of DNA be compared among different species

Answer 21

To determine phylogenetic relationships

Question 22

What is the difference in DNA between closely related organisms

Answer 22

They contain similar DNA compliments but are often arranged differently on the chromosomes

Question 23

The 3 divisions/domains of the living world

Answer 23

Bacteria
Archaea
Eukaryotes

Question 24

4 main processes for generating change in a genome

Answer 24

1. Intragenic mutation (single base change/point mutations/changing AA composition)
2. Gene duplication
3. DNA segment shuffling (mixing of segments of 1 gene with those of another)
4. Horizontal transfer (from one cell/organism to another)

Question 25

What is different about bacterial genes

Answer 25

They are usually clustered into groups (operons) that are transcribed as a single unit

Question 26

Non-coding region of DNA

Answer 26

intron

Question 27

What is the difference in genes between closely related species

Answer 27

Exons are very similar (conserved) | Introns vary in size and content

Question 28

Do bacteria have introns? Why?

Answer 28

No, bacterial chromosomes are densely packed with genes, leaving very little DNA that is non-coding

Question 29

What is different about the DNA in higher eukaryotes

Answer 29

Most of it does not code for proteins | It is made up of repeated sequences, many of which are mobile elements that can move around in the genome

Question 30

What is the shape of bacterial and eukaryotic chromosomes?

Answer 30

``` Bacterial = Circular Eukaryotic = Linear ```

Question 31

DNA polymerase is a ___ dependent ___ synthesizing enzyme

Answer 31

DNA | DNA

Question 32

RNA polymerase is a ___ dependent ___ synthesizing enzyme

Answer 32

DNA | RNA

Question 33

Reverse transcriptase is a ___ dependent ___ synthesizing enzyme

Answer 33

RNA | DNA

Question 34

Primase is a ___ dependent ___ polymerase

Answer 34

DNA | RNA

Question 35

Role of primase

Answer 35

Synthesizes a small RNA primer that can be used by the DNA polymerase to elongate the chain

Question 36

_____ minimizes the number of mistakes by using a _ to _ ______ activity that is part of the same protein

Answer 36

DNA polymerase | 3' to 5' exonuclease

Question 37

DNA polymerase as well as all other nucleic acid polymerases synthesize DNA in the _ to _ direction only

Answer 37

5' to 3'

Question 38

During _____, each new nucleotide is added to the _ carbon on the last nucleotide of the new DNA chain

Answer 38

replication | 3'

Question 39

Differences between the carbons in 5-C sugars

Answer 39

1' - connects the base component of each nucleotide 2' - differs between RNA and DNA 3' and 5' - Adjacent nucleotides attach here in a DNA chain

Question 40

DNA polymerase is an ____ enzyme; it cannot _____ synthesis. A ___ is required for elongation of a new strand using DNA polymerase

Answer 40

Elongating Initiate Primer

Question 41

Bacterial chromosomes contain ____ origin(s) of replication

Answer 41

One

Question 42

What is the direction of DNA synthesis?

Answer 42

It proceeds in both directions away from the origin until the two replication forks meet at a specific sequence on the other side of the chromosome

Question 43

What is different about the origin of replication in eukaryotes?

Answer 43

They contain many origins of replication that may change during the development of the organism

Question 44

Telomeres

Answer 44

Special structures placed at each end of linear eukaryotic chromosomes

Question 45

Telomeres are constructed with the enzyme ____ that uses a ___ template to synthesize a short repeated DNA sequence at the ends of chromosomes

Answer 45

Telomerase | RNA

Question 46

Because polymerase synthesizes DNA in the 5' to 3' direction, the two polymersae molecules must move _____ each other

Answer 46

Opposite

Question 47

Helicase function

Answer 47

Unwinds 2 DNA strands before polymerization of the new strands

Question 48

_____ keep the two complementary strands from reforming a double helix

Answer 48

Single-stranded binding proteins

Question 49

The polymerase on the leading strand moves ___ the replication fork and the one on the lagging strand moves ____ it

Answer 49

Toward | Away from

Question 50

The lagging strand is synthesized in short strands called

Answer 50

Okazaki fragments

Question 51

____ initiates synthesis of each Okazaki fragment by making a short ___ primer

Answer 51

Primase | RNA

Question 52

What signals that the DNA is unreplicated and ready to be used as a template for the next round of synthesis?

Answer 52

Methylation of the DNA

Question 53

Breaks in DNA (especially ___ breaks) facilitate initiation of _______

Answer 53

Double-stranded | Recombination

Question 54

A defect in _____ can cause abnormal amounts of recombination

Answer 54

DNA ligase

Question 55

This is the reciprocal exchange of genetic information

Answer 55

Recombination

Question 56

Recombination can be the result of

Answer 56

1. Reciprocal exchange during cell division 2. DNA damage (ex. X-ray damage) 3. Introduction of foreign DNA 4. Programmed recombination during development or maturation of a cell type (ex. antibody producting genes during B-cell maturation)

Question 57

This is the non-reciprocal exchange of genetic information

Answer 57

Gene conversion

Question 58

Can circular DNA be inserted into a chromosome?

Answer 58

Yes, via recombination between a region on a circular molecule and a homologous region on the chromosome

Question 59

What do x-rays do to DNA?

Answer 59

Cause breaks and induce recombination

Question 60

What species have transposable elements?

Answer 60

Everything from bacteria to human

Question 61

What do transposable elements do?

Answer 61

Move from one location in DNA to another location in cell. Can cause changes in DNA at site of insertion

Question 62

Two major types of transposable elements

Answer 62

1. Contains inverted repeated sequences at the ends and causes a short region of genome to be duplicated at site of insertion 2. Structurally similar to a retrovirus and trasposes through an RNA intermediate

Question 63

Recombination that resulted from imprecise pairing of tandemly repeated sequences is ___

Answer 63

Unequal crossing-over

Question 64

Results of unequal crossing-over

Answer 64

Loss or gain of gene copies

Question 65

Two types of mutations

Answer 65

1. DNA rearrangements | 2. Base substitutions

Question 66

Is a cell able to repair its DNA?

Answer 66

Yes, there are many mechanisms for it

Question 67

A permanent mutation results from

Answer 67

Damage to a nucleotide (ex. deamination) that cannot be repaired

Question 68

Causes of mutations

Answer 68

Errors during replication | Injury to the DNA from chemicals or radiation

Question 69

About 3% of the human genome is this

Answer 69

Made up of segmental duplications or large regions of DNA that are present in more than one copy

Question 70

What process creates duplicated DNA in a genome

Answer 70

Gene amplification

Question 71

Results of gene amplification

Answer 71

Resistance to drugs Transformation into cancerous cells Other changes in cell phenotype

Question 72

Should I worry about defects in my DNA repair enzymes?

Answer 72

HOLY FUCKSTICKS BATMAN, YES! THEY CAN BE THE CAUSE SEVERAL HUMAN DISEASES.