Chapter 8

Question 1

Define genetics

Answer 1

The study of genes, how they carry information, how information is expressed, and how genes are replicated

Question 2

Define Chromosomes

Answer 2

Structures containing DNA that physically carry herediary information; the chromosomes contain genes

Question 3

Define Genes

Answer 3

Segments of DNA that encode functional products, usually proteins

Question 4

Define Genome

Answer 4

All the genetic information in a cell

Question 5

What is the genetic code?

Answer 5

A set of rules that dtermines how a nucleotide sequence is converted to an amino acid sequence of a protein

Question 7

Define genotype

Answer 7

The genetic makeup of an organism

Question 8

Phenotype

Answer 8

Expression of the genes (hair color, eye color, etc)

Question 9

Vertical gene transfer

Answer 9

Flow of genetic information from one generation to the next

Question 10

DNA forms a ____ ______

Answer 10

Double helix

Question 11

What does the “backbone” of DNA consist of?

Answer 11

Deoxyribose-phosphate

Question 12

Fill in the blanks

DNA Replication

• “Backbone” consists of _____-______
• Twostrands of nucleotides are held together by hydrogen bonds between ____ and _____
• Strands are ________ in arrangement
• Order of the ___________ bases forms the _______ ____ of the organisms

Answer 12

• deoxyribose-phosphate
• A-T and C-G
• Antiparrallel
• nitrogen-containing; genetic instructions

Question 13

How many strands serve as the template for the production of a second strand?

Answer 13

1

Question 14

Topoisomerase and gyrase - they ____ and ____ the strands

Answer 14

twist; relax

Question 15

_______ separates the DNA strands during DNA replications

Answer 15

Helicase

Question 16

During DNA replication what makes a molecule of DNA? How does it do this?

Answer 16

DNA polymerase;

It adds nucleotides to the growing DNA strand

Question 17

Which direction does DNA polymerase go?

Answer 17

5’-3’ direction

Question 18

The process of DNA ploymerase adding nucleotides to the growing DNA strand is initiated by a_______ _____.

The leading strand is synthesized _______ while the lagging strand is synthezised ________, creating ___________ ______

Answer 18

RNA primer

continually

discontinually

okazaki strands

Question 19

Towards end of DNA replication DNA polymerase removes ____ ____; ____ ___ are joined by _____ ____ and ____ _______

Answer 19

RNA primers

Okazaki fragments

DNA polymerase and DNA ligase

Question 20

Energy for DNA replication is supplied by _____.

_____ of two phopshate groups on _____ provides energy

Answer 20

Nucleotides

Hydrolysis; ATP

Question 21

DNA replication is ________ which means what?

Answer 21

Semiconservative; This means each new double stranded DNA molecule contains one original strand and one new strand

Question 22

Most bacterial DNA replication is ________

Answer 22

Bidirectional

Question 23

How many copies of the DNA molecule can each offpsring of DNA replication receive?

Answer 23

One

Question 24

Is DNA replication accurate? If so, why?

Answer 24

Yes because of the proofreading capabilities of the DNA polymerase.

Question 25

What three things do you know about Ribonucleic acid?

Answer 25

* Single-stranded nucleotide * 5-carbon ribose sugar * Contains uracil (U) insteadof thymine (T)

Question 26

What is the integral part of ribosomes?

Answer 26

Ribosomal RNA (rRNA)

Question 27

What transports amino acids during protein synthesis?

Answer 27

Transfer RNA (tRNA)

Question 28

What carries coded information from DNA to ribosomes?

Answer 28

Messenger RNA (mRNA)

Question 29

Transcription proceeds in the ___ -\> ___ direction. It stops when it reaches the ____ sequence on DNA. Transcription begins when ___ \_\_\_\_\_ binds to the _____ sequence on DNA. What is synthesized during transcription in prokaryotes?

Answer 29

* 5 3 * terminator * RNA polymerase ; promoter * Sntehsis of a complementary mRNA strand from a DNA template

Question 30

mRNA is translated into the _______ of proteins

Answer 30

"language"

Question 31

Codons

Answer 31

Groups of three mRNA nucleotides that code for a particular amino acid

Question 32

\_\_\_ ___ \_\_\_\_ encode 20 amino acids

Answer 32

61 sense codons

Question 33

Degeneracy

Answer 33

Genetic code involves degeneracy - each amino acid is coded by several codons (translation)

Question 34

What is the start codn? What does this do?

Answer 34

AUG; translation of mRNA begins at the start codon

Question 35

3 nonsense codons

Answer 35

UAA, UAG, UGA

Question 36

Codons of rRNA are ____ sequentially

Answer 36

"read"

Question 37

tRNA molecules transport the required ____ \_\_\_ to the ribosome tRNA molecules also have a ______ that base-pairs with the codon Amino acids are joined by _____ \_\_\_\_

Answer 37

* amino acids * anticodon * peptide bonds

Question 38

In bacteria, translation can beginn _____ transcription is complete.

Answer 38

before

Question 39

Mutation

Answer 39

A permanent change in the base sequence of DNA

Question 40

Mutations may be \_\_\_\_\_\_\_, \_\_\_\_, or \_\_\_\_

Answer 40

Mutual, beneficial, harmful

Question 41

Mutagens

Answer 41

Agents that cause mutations

Question 42

Spontaneous mutations

Answer 42

Occur in the absence of a mutagen

Question 43

Base substitution

Answer 43

(point mutation) Change in one base in DNA

Question 44

Missense mutation

Answer 44

Base substitution results in change in an amino acid

Question 45

Base substitution results in a nonsense (stop) codon

Answer 45

Nonsense mutation

Question 46

Base substitution results in change in an amino acid

Answer 46

Missense mutation

Question 47

Change in one base in DNA

Answer 47

Base substitution

Question 48

Insertion or deletion of one or more nucleotide pairs Shifts the translational "reading frame"

Answer 48

Framshift mutation

Question 49

Causes adenine to bind with cytosine instead of thymine

Answer 49

Nitrous acid

Question 50

Incorporates into DNA in place of a normal base; causes mistakes in base pairing

Answer 50

Nucleosid analog

Question 51

Causes the formation of ions that can ozidize nucleotides and break the deoxyribose-phosphate backbone

Answer 51

Ionizing radiation

Question 52

Causes thymine dimers

Answer 52

UV radiation

Question 53

Separate thymine dimers

Answer 53

Light repair-photolyases

Question 54

Enzymes cut out incorrect bases and fill in corect bases

Answer 54

Nucleotide excision repair

Question 55

Detects mutant cells because they grow or appear idifference than unmutated cells

Answer 55

Positive (direct) selection

Question 56

Detects mutant cells that cannot grow or perform a certain function

Answer 56

Negative (indirect) selection

Question 57

Mutant that has a nutritional requirement absent in the parent

Answer 57

Auxtotroph Use of replica plating

Question 58

Test that exposes mutant bacteria to mutagenic substances to measure the rate of reversal of themutation What does it indicate?

Answer 58

Ames test Degree to which a substance is mutagenic