chpt 14 molecular genetics

Question 1

What are chromosomes ?

Answer 1

1. dna folded and coiled to wrap around special proteins called histones and fit inside the cell
2. highly compacted dna is then arranged into structures called chromosomes

Question 2

What are genes ?

Answer 2

1. sequence of dna nucleotides
2. each gene encoded for the synthesis of a single polypeptide -> can be used to make proteins

Question 3

What is transcription ?

Answer 3

1. the process of transcription takes place in the nucleus
2. dna strand untwists and unzips, H bonds btwn strands break
3. dna strand provides a template for the complementary mRNA strand
4. complementary rna molecule is synthesised according to base pairing rules, except uracil is paired with adenine
5. mrna leaves nucleus through pores and enters the cytoplasm,

Question 4

What is translation ?

Answer 4

1. mrna strand attaches to ribosome
2. each mrna codon codes for a specific amino acid
3. trna molecules transport specific amino acids to the ribosome
4. anti codon and codon match up to form complementary base pairs
5. codon by codon, ribosomes adds each amino acid carried by the trna to the growing chain of polypeptides
6. amino acids are joined together by peptide bonds