DNA and GENE Expression

Question 1

four types of nucleotides

Answer 1

Adenine A, Guanine G, Thymine T, Cytosine C

Question 2

complementarity

Answer 2

makes it possible for DNA to copy itself in preparation for cell division

Question 3

shape of a DNA molecule

Answer 3

DNA molecule is a double helix, shaped like a twisted ladder

Question 4

DNA replication

Answer 4

it produces two identical replicas from one original DNA molecule; located in nucleus

Question 5

three enzymes involved in DNA replication the process and their functionality

Answer 5

Helicase: unwinds the DNA (breaking hydrogen bonds)

DNA polymerase: adds a complementary nucleotide to the growing DNA strand and requires a primer

DNA ligase: seals DNA fragments together

Question 6

RNA polymerase

Answer 6

an enzyme that produces the messenger RNA (mRNA) during transcription by binding to one DNA strand at a promoter site

Question 7

steps involved in gene expression

Answer 7

Transcription and Translation

Question 8

where gene expression takes place

Answer 8

in the nucleus

Question 9

transcription

Answer 9

first step of gene expression, in which DNA is copied into RNA by the enzyme RNA polymerase creating messenger RNA

Question 10

translation

Answer 10

a gene of DNA is transcribed into mRNA. mRNA translates the

production of a protein

Question 11

gene expression

Answer 11

use of information in DNA to direct the production of proteins

Question 12

gene

Answer 12

small DNA sequence that directs the synthesis of a specific protein, the molecular unit of heredity of a living organism

Question 13

ribosome

Answer 13

a cellular organelle that is the site of protein synthesis, it consists of small and large subunits, a complex of proteins & several segments of ribosomal RNA

Question 14

universal genetic code

Answer 14

three-letter code defining the transfer of the information from nucleic acids to proteins. codon in humans, does the same in prokaryotes

Question 15

codon

Answer 15

three adjacent nucleotides along a DNA or messenger RNA molecule that designates a specific amino acid to be incorporated into a polypeptide.

Question 16

anticodon

Answer 16

triplet of nucleotides in transfer RNA that is complementary to the codon in messenger RNA which specifies the amino acid

Question 17

DNA structure in eukaryotes and prokaryotes (exons and introns)

Answer 17

Eukaryotes - exons are interrupted by non-coding sections of DNA, introns

Prokaryotes - gene is an uninterrupted stretch of DNA nucleotides that corresponds to proteins

Question 18

mutations

Answer 18

any change in the DNA sequence

Question 19

mutagens

Answer 19

substances inducing mutations

Question 20

difference between induced and spontaneous mutation

Answer 20

induced- caused by (mutagens)

spontaneous mutation- caused by errors in DNA replication

Question 21

three types of RNA

Answer 21

mRNA , tRNA, rRNA

Question 22

mRNA

Answer 22

synthesised in the nucleus. It is a copy of the genetic code held in DNA. It then passes out into the cytoplasm of the cell to be involved in protein synthesis

Question 23

tRNA

Answer 23

synthesised in the nucleus using DNA as a template. It assembles into a clover leaf shaped molecule which passes out into the cytoplasm where it attaches itself to a specific amino acid molecule. Its job is to bring the amino acids to the site of protein synthesis.

Question 24

rRNA

Answer 24

synthesised in the nucleolus. rRNA leaves the nucleus where it forms ribosomes.The role of proteins in the formation of a phenotype