genetics

Question 1

gene

Answer 1

a heritable factor that consists of a length of DNA and influences characteristics

Question 2

locus

Answer 2

position of a gene on a chromosome

Question 3

Allele

Answer 3

A specific form of a gene

Question 4

Types of dna

Answer 4

-introns
-exons
-highly repetitive sequences
-structural dna (telomeres, centromeres)
- inactive genes
Other

Question 5

Short tandem repeats

Answer 5

In polymorphisms (areas of dna that are unique to each individuals)

Question 6

A C G T U

Answer 6

adenine cytosine guanine thymine uracil

Question 7

characteristics of dna

Answer 7

antiparallel strands double helix hydrogen bonds between two strands

Question 8

A-T

Answer 8

two hydrogen bonds

Question 9

C-G

Answer 9

three hydrogen bonds

Question 10

nucleosome

Answer 10

8 histone proteins; help to organise DNA, prevent random transcription

Question 11

Hershey and Chase experiment

Answer 11

radioactive S (protein coats) and P (DNA) in bacteriophages and after infecting bacteria found that genetic inf stored by DNA

Question 12

DNA polymerase III

Answer 12

catalyses creation of covalent bonds between 3’ and 5’ ends of new nucleotide (5->3 direction)

Question 13

DNA polymerase I

Answer 13

removes RNA primer of Okazaki fragments and replaces RNA nucleotides with DNA nucleotides

Question 14

DNA ligase

Answer 14

catalyses formation of covalent bonds between Okazaki fragments

Question 15

DNA helicase

Answer 15

unwinds the double helix by breaking hydrogen bonds

Question 16

DNA primase

Answer 16

binds nucleotides of RNA primer together

Question 17

DNA gyrase

Answer 17

prevents DNA from getting tangled by breaking it at strain points; relieves the strain on the “twisted side” by supercoiling

Question 18

single strand binding proteins (SSBs)

Answer 18

prevents reformation of the double helix of the separated strands; prevents the strand from being digested; allows enzymes to work effectively

Question 19

Okazaki fragments

Answer 19

from the lagging strand, 100-200 nucleotides; sticked together by DNA ligase

Question 20

stopping DNA replication

Answer 20

dideoxyrybonucleoside replaces one nucleoside and next covalent bond can’t be formed

Question 21

Meselson and Stahl’s experiment

Answer 21

N15 atoms (heavier) used to grow bacteria; provided proof that DNA replication is semi conservative

Question 22

transcription

Answer 22

the process of obtaining mRNA from DNA template; takes place in the nucleus

Question 23

Initiation of transcription

Answer 23

RNA polymerase binds to the promoter ( specific base sequence that is non coding)

Question 24

Elongation of transcription

Answer 24

RNA polymerase unwinds the DNA strand (H bonds breaking) and attaches individual nucleotides together to form a single strand of RNA

Question 25

termination of transcription

Answer 25

terminator transcribed, RNA fold back on itself and detaches

Question 26

5’ cap

Answer 26

7-methylguanosine added after 5’ phosphate is removed; regulator function

Question 27

poly(A) tail

Answer 27

multiple adenosine monophosphates added to 3’ end; enhance stability

Question 28

splicing

Answer 28

removing introns, leaving exons; allows for multiple proteins to be created from the same DNA sequence