Chapter 7

Question 1

DNA

Answer 1

Deoxyribonucleic acid

Question 2

3 Prime and 5 Prime (3’ and 5’)

Answer 2

Nucleotides join together to form a chain and at the same end of the double helix, one chain therefore ends with a free (unbound) 3’ carbon while the other chain ends with a free (unbound) 5’

Question 3

Complementary

Answer 3

2 strands of DNA are complementary to each other. The sequence of each strand defines the sequence of the other

Question 4

Genome

Answer 4

All of the genetic material in an organism’s cells

Mainly consists of one circular DNA Molecule

Question 5

Chromosome

Answer 5

Houses in the cells nucleus, a chromosome is a discrete package of DNA and associated proteins

Question 6

Gene

Answer 6

Sequence of DNA nucleotides that code for a specific protein or RNA molecule

Question 7

Transcription

Answer 7

In protein production, A cell copies a gene’s DNA sequence to. Complementary RNA molecule

Question 8

Translation

Answer 8

In protein production, the info in RNA is used to manufacture a protein by joining a specific sequence of amino acids into a polypeptide chain

Question 9

Messenger RNA (mRNA)

Answer 9

Carries info that specifies a protein.

Question 10

Codon

Answer 10

Each group of 3 mRNA bases in a row forms a codon.

Codon is a genetic code word that corresponds to one amino acid

Question 11

Ribosomal RNA (rRNA)

Answer 11

Combine with proteins to form a ribosome. Some help to correctly align the ribosome and mRNA and other catalyze formation of the bonds between amino acids in the developing protein

Question 12

Ribosome

Answer 12

Physical location of protein synthesis

Question 13

Transfer RNA (tRNA)

Answer 13

Connectives that bind mRNA codon at one end and a specific amino acid at the other. There carry each amino acid to the ribosome along the mRNA molecule

Question 14

Template strand

Answer 14

Strand in the DNA molecule that is copied to RNA

Question 15

Transcription step 1: initiation

Answer 15

Enzymes unzip the DNA double helix to expose the template strand. RNA polymerase binds to the promoter

Question 16

RNA polymerase

Answer 16

The enzyme that builds up an RNA chain

Question 17

Promoter

Answer 17

A DNA sequence that signals the gene’s start

Question 18

Transcription step 2: elongation

Answer 18

RNA polymerase moves along the DNA template strand in a 3’ to 5’ direction, adding nucleotides only to the 3’ end

Question 19

Transcription step 3: termination

Answer 19

Once the terminator sequence is reached, the RNA polymerase enzyme separates from the DNA template and releases the newly synthesized RNA. DNA resumes its usual double helix shape

Question 20

Terminator sequence

Answer 20

Signals the end of the gene

Question 21

Introns

Answer 21

Portions of the mRNA that are removed before translation by small catalytic RNAs and proteins

Question 22

Exons

Answer 22

Remaining proteins that are spliced together to form the mature mRNA that leaves the nucleus to be translated

Question 23

Anticodon

Answer 23

A three-base loop that is complemtary to one mRNA codon

Question 24

Translation step 1: initiation

Answer 24

Sequence at the 5’ end of the mRNA molecule bonds with a small ribosomal subunit. A large ribosomal subunit attaches to the small subunit to complete initiation

Question 25

Translation step 2: Elongation

Answer 25

A tRNA molecule carrying the second amino acid then binds to the second codon. The two amino acids align and a convalent bond forms between them. Ribosome then releases the first tRNA. The ribosome moves down the mRNA. Polypeptide grows one amino acid at a time as tRNAs continue to deliver their cargo

Question 26

Translation step 3: termination

Answer 26

Elongation halts at a stop codon (UGA, UAH, or UAA). Proteins called release factors bind to the stop codon and the ribosome releases the last tRNA, the ribosomal subunits separate and are recycled, and the new polypeptide released

Question 27

Operon

Answer 27

A group of related genes plus a promoter and an operator that control the transcription of the entire group at once

Question 28

Operator

Answer 28

A DNA sequence located between the promoter and the protein encoding regions

Question 29

Depressor

Answer 29

A proteins that prevents the transcription of genes if it binds to the operator

Question 30

Transcription factors

Answer 30

Bind DNA at specific sequences that regulate transcriptions. RNA polymerase cannot bind to a promoter or initiate transcription in the absence of transcription factors

Question 31

Enhancer

Answer 31

A regulatory DNA sequence that lies outside the promoter that a transcription factor may bind to.

Question 32

Mutation

Answer 32

A change in a cells DNA sequence either in a protein coding gene or in a no coding DNA such as an enhancer

Question 33

Substitution mutation

Answer 33

The replacement of one DNA base with another

Question 34

Frameshift mutation

Answer 34

Nucleotides are added or deleted by a number other than a multiple of three. Likely to alter the sequence of amino acids or cause premature stop codons

Question 35

Expanding repeat mutation

Answer 35

The number of copies of three- or four- nucleotide sequence increases over several generations. With each generation the symptoms begin earlier or become more severe

Question 36

Mutagen

Answer 36

any external agent that induce mutations (UV radiation from sunlight, X-rays, chemicals)

Question 37

Transposable element

Answer 37

Transposon. A DNA sequence that can jump within a genome. It can insert i tasks randomly into chromosomes and interrupt the gene’s function

Question 38

Germline mutation

Answer 38

A DNA sequence change that occurs in the cells that give rise to sperm or eggs

Question 39

Somatic mutation.

Answer 39

Occurs in nonsex cells. All cells derived from the altered one will also carry the mutation but the mutation does not pass to the organisms offspring

Question 40

Alleles

Answer 40

Variants of genes

Question 41

RNA

Answer 41

Ribonucleic acid