Chapter 12:gene expression At Molecular Level

Question 1

Gene

Answer 1

Organized unit of DNA sequences that enables segment of DNA to be transcribed into RNA and ultimately results in formation of a functional product

Question 2

Mutations

Answer 2

Changes in genetic material that can be inherited

Question 3

Inborn error of metabolism

Answer 3

Error that refers to a mutation in a gene that is inherited from one or both parents

Question 4

One gene/one enzyme hypothesis

Answer 4

Single gene controlled the synthesis of a single enzyme

Question 5

Transcription

Answer 5

Produces an RNA copy of a gene, called an RNA transcript

Question 6

Structural genes

Answer 6

Produce an RNA molecule that contains the information to specify a polypeptide

Question 7

MRNA

Answer 7

the messenger RNA that carries information from the DNA to cellular components called ribosomes

Question 8

Translation

Answer 8

Process of synthesizing a specific polypeptide from an mRNA template on a ribosome

Question 9

Central dogma

Answer 9

DNA To RNA to polypeptide

Question 10

RNA modification

Answer 10

The RNA transcript is modified in ways that make it functionally active mRNA

Question 11

Where do transcription and translation occur in eukaryotes?

Answer 11

Transcription occurs in the nucleus and then the mRNA exits the nucleus and translation occurs in the cytosol

Question 12

Transfer RNA

Answer 12

• product of non structural genes

- translates the language of mRNA into that of amino acids

Question 13

Ribosomal RNA

Answer 13

• product of nonstructural genes

- forms pet of ribosomes which provide site where translation occurs

Question 14

Promoter region

Answer 14

Sequence of DNA that controls when and where transcription will begin

Question 15

Terminator

Answer 15

Specifies end of transcription

Question 16

3 stages of transcription

Answer 16

Initiation, elongation, and termination

Question 17

Initiation

Answer 17

The recognition of the promoter region to start the process

-initiation is over when DNA strands are separated near promoter

Question 18

RNA polymerase

Answer 18

Enzyme that synthesizes strands of RNA

Question 19

Elongation step of transcription

Answer 19

RNA polymerase synthesized the RNA transcript

Question 20

Template strand of DNA

Answer 20

DNA that is used as template to make RNA

Question 21

Coding strand of DNA

Answer 21

Opposite DNA strand that will ultimately resemble the produced rna

Question 22

Termination step of transcription

Answer 22

RNA polymerase reaches a terminator and the newly made rna transcript dissociates from the DNA strand

Question 23

Template strand is read in…

Answer 23

3’ to 5’ direction

Question 24

Transcription factors

Answer 24

Proteins that influence the ability of RNA polymerase to transcribe genes

Question 25

Exons

Answer 25

The expressed regions of the pre mRNA that are connected together during splicing

Question 26

Introns

Answer 26

These are non coding parts of the pre-MRNA that intervene and do not code for a protein

Question 27

RNA splicing

Answer 27

Introns are removed and remaining expand are connected to each other

Question 28

5' cap

Answer 28

Pre mRNA receives a 5' cap of guanine that helps prevent degradation and helps it bind to a ribosome in cytosol

Question 29

Poly A tail

Answer 29

Added to the 3' end and is not included in gene sequence but is added enzymatically -long poly A tail aids in export of mRNA and causes it to be more stable

Question 30

Sliceosomes

Answer 30

How introns are removed and they consist of different snRNPS that splice at 5' splice and 3' splice and help move exons closer together

Question 31

Alternative splicing

Answer 31

Splicing can occur in multiple ways and this allows a single gene to encode two or more polypeptides with differences in amino acid sequences

Question 32

Metabolic pathway

Answer 32

Series of chemical reactions occuring within a cell. These reactions are catalyzed by enzymes, where the product of one enzyme acts as the substrate for the next

Question 33

Phosphodiester bonds

Answer 33

Make up the backbone of the strands of nucleic acids

Question 34

Structural gene

Answer 34

Gene that encodes for any rna or protein product other than a regulatory factor

Question 35

Sigma factor

Answer 35

Protein needed only for initiation of RNA synthesis (bacterial transcription initiation factor)

Question 36

Genetic code

Answer 36

Set of rules by which information encoded within genetic material is translated into proteins by living cells

Question 37

In bacteria where do transcription and translation occur?

Answer 37

In the cytoplasm

Question 38

Regulatory proteins

Answer 38

To influence the rate of transcription

Question 39

Pre-initiation complex

Answer 39

Transcription factors and rna polyermase assemble into preinitiation complex at the promoter

Question 40

Transcription factors

Answer 40

Proteins that influence the ability of rna polymerase to transcribe genes

Question 41

Start codon

Answer 41

A codon that specifies the first amino acid in a polypeptide sequence

Question 42

Coding sequence of mRNA

Answer 42

A series of codons from the start codon to the stop codon that determine the sequence of amino acids of a polypeptide

Question 43

N terminus

Answer 43

The first amino acid is said to be at the amino end

Question 44

C terminus

Answer 44

The last amino acid is said to be located at the carboxyl end

Question 45

tRNA

Answer 45

A molecule with two functional sites: one site termed the anticodon binds to a codon in mRNA and the second site is where an appropriate amino acid is attached

Question 46

Initiation in translation

Answer 46

mRNA, tRNA, and the ribsomal subunits form a complex

Question 47

Elongation in translation

Answer 47

Ribosome travels in the 5' to 3' direction and synthesizes a polypeptide

Question 48

Termination in translation

Answer 48

The ribosome reaches a stop codon, and all of the components disassemble, releasing a completed polypeptide

Question 49

How many codons are there?

Answer 49

64

Question 50

First amino acid in every sequence...

Answer 50

Methionine