Topic 6 Difficult

Question 1

describe protein synthesis

Answer 1

a sequence of 3 bases (triplet code) code for 1 specific amino acid
order of bases controls order that amino acids are joined to make a specific protein

1. one gene codes for a specific template of complementary bases
2. template (mRNA=single strand) carries code for making a protein from nucleus to ribosomes
3. carrier molecules bring correct amino acids in correct order to ribosomes
4. ribosome reads code & makes the specific sequence of amino acids to make specific protein
5. when protein chain is complete it folds into a specific shape which enables protein to do its function

Question 2

what are 3 functions of proteins?

Answer 2

1. enzymes - biological catalysts
2. hormones e.g. insulin
3. structural components e.g. collagen (strengthens connective tissues)

Question 3

what was discovered in late 19th century?

Answer 3

chromosomes

Question 4

was discovered in early 20th century?

Answer 4

genes discovered as units on chromosomes

Question 5

was discovered in mid 20th century?

Answer 5

the structure of DNA

Question 6

how are fossils formed?

Answer 6

1. animal traces e.g. footprints, burrows, rootlets
2. animal decayed so left space that was filled by minerals
3. parts of organism had not decayed because a condition for decay was not present (e.g. anaerobic, low temp, low pH, low moisture)

Question 7

why are scientists unsure about early life on earth?

Answer 7

most traces/fossils have been destroyed

Question 8

how are fossils destroyed?

Answer 8

geological activity

Question 9

what factors can cause extinction of a few species? (not mass extinction)

Answer 9

1. new predator
2. new pathogen
3. new competitor