DNA and RNA

Question 1

define gene

Answer 1

a section of DNA that causes the production of a protein

Question 2

what are chromosomes made of

Answer 2

DNA + protein

Question 3

how much DNA is used for coding proteins

Answer 3

3%

Question 4

what is junk DNA

Answer 4

non coding DNA

Question 5

where are chromosomes found

Answer 5

nucleus

Question 6

when chromosomes are not dividing what do they form

Answer 6

chromatin

Question 7

what form of bonding holds DNA together

Answer 7

hydrogen bonds

Question 8

what is a nucleotide composed of

Answer 8

phosphate + base + sugar (deoxyribose)

Question 9

what are pyrimidines

Answer 9

single ring shaped molecule (thymine and cytosine)

Question 10

what are purines

Answer 10

double ring shaped molecule (adenine and guanine)

Question 11

what base differs in DNA than RNA

Answer 11

RNA has uracil rather than thymine

Question 12

what is a codon

Answer 12

a triplet of bases e.g CAA codes for Valine

Question 13

explain DNA replication

Answer 13

double helix unwinds, enzymes break down hydrogen bonding, free floating nucleotides in the cytoplasm enter the nucleus and attach to complimentary base pairs… creates a new DNA strand which rewinds to form a new double helix

Question 14

what is DNA profiling

Answer 14

a method of making a unique pattern of bands from a person’s DNA which can be compared to another person’s DNA

Question 15

what can DNA profiling be used for

Answer 15

crime; biological evidence can be compared to suspect. can be used in medical, paternity and maternity tests

Question 16

describe the process of DNA profiling

Answer 16

DNA is released from cells, cut into different sized fragments using restriction enzymes, fragments are separated by their size by a process called gel electrophoresis which produces a unique pattern in the gel, patterns are then stained and compared

Question 17

what is genetic screening

Answer 17

testing DNA for the presence/absence of a particular of a particular or an altered gene

Question 18

what sort of diseases might be tested for using genetic screening

Answer 18

sickle cell anemia, cystic fibrosis, hereditary cancers

Question 19

explain protein synthesis

Answer 19

enzymes unwind and unzip the DNA to expose the compimentary base pairs. transcription then occurs- RNA nucleoides move from cytoplasm and join to the exposed complimentary base pairs. RNA polymerase joins the bases together to form mRNA. mRNA goes to ribosomes and forms a weak bond with rRNA . tRNA moves into ribosome and brings amino acids with it + attaches to mRNA after the start codon. tRNA leaves ribosome and pulls mRNA strand through the ribosome. this continues until a protein is formed. proteins are then folded into the correct shape