Inheritance, Variation And Evolution

Question 1

How do cells divide to form gametes ? (3)

Answer 1

• copies of genetic information are made
• the cell divides twice to form 4 gametes each with 23 chromosomes.
• all gametes genetically different

Question 2

What are the steps of protein synthesis work ?

Answer 2

Transcription and translation.

Question 3

What is a chromosome ?

Answer 3

Strands of DNA
Made of protein

Question 4

What are the two kinds of DNA ?

Answer 4

Coding and Non-coding.

Question 5

What does non coding DNA do ?

Answer 5

Can switch genes on and off
So variations in these areas of DNA may affect how genes are expressed.

Question 6

What does coding DNA do ?

Answer 6

Codes for a specific protein.

Question 7

What is the pair of chromosomes for a female ?

Answer 7

XX

Question 8

How are cells genetically engineered ? (4)

Answer 8

• Enzymes used to isolate the required gene (sticky ends)
• Gene inserted into vector ( usually bacteria )
• Vector used to insert gene into the required cells. (Also opened by enzymes)
  Genes are transferred into cells of organisms in early stage of development so they develop with desired characteristics.

Question 9

How does tissue culture work ?
What’s it good for ?

Answer 9

Small groups of cells separated with enzymes, grow in lab conditions.
Good for preserving rare species.

Question 10

Darwin ?

Answer 10

Finches
Natural selection
Challenges idea that God made animals, insufficient evidence.

Question 11

Wallace ?

Answer 11

Theory of evolution
Speciation

Question 12

Mendel ?

Answer 12

Inheritance of plants (peas) determined my units (alleles)

Published in not well known science magazine.
He could not explain the science behind why they were inherited..

Question 13

What is the binomial system ?

Answer 13

Way of naming organisms - Genus and species

Question 14

Carl Linnaeus?

Answer 14

Kingdom phylum class order family genus species

Question 15

What classification system did Carl woes create ?

Answer 15

Three domain system
Archaea
Bacteria
Eukaryota

Question 16

Why did Carl worse create a new system ?

Answer 16

More info and evidence available on internal structures due to microscopes.

Question 17

Development of antibiotics is…

Answer 17

Costly and slow.

Question 18

What are the steps of transcription ?

Answer 18

1 - the two strands of DNA are separated using enzymes by breaking hydrogen bonds between bases.
2 - the enzyme RNA polymerase attaches to DNA in non-coding region and reads the gene.
3 - RNA polymerase moved along DNA strand free RNA nucleotides form hydrogen bonds with complementary exposed DNA strand nucleotides forming a mRNA strand (t replaced with u)
4 - mRNA strand moved out of nucleus to ribosome.

Question 19

What are the steps of translation ?
(6)

Answer 19

1 - mRNA strand attaches to ribosome
2 - a codon ( 3 bases ) code for complementary molecule of tRNA
3 - tRNA with complementary anticodon bring the specific amino acid
4 - the tRNA then leaves to pick up another specific amino acid
5 - the process is repeated specific to each codon and peptide bonds form between amino acids.
6 - polypeptide forms and folded into specific protein.