DNA + Genome

Question 1

what is the genome?

Answer 1

complete set of genes in an organism

Question 2

what are exons?

Answer 2

regions of DNA that code for an amino acid

Question 3

what are introns?

Answer 3

non-coding DNA

Question 4

differences between pro + euk dna

Answer 4

prokaryote eukaryote
- DNA not in nucleus - DNA in nucleus
* DNA circular * DNA is linear
* DNA is naked * DNA associated with histones
* Shorter DNA * Longer DNA
* DNA contains no introns * DNA contains introns
- Has plasmids - doesn’t have plasmids

Question 5

what does degenerate code mean?

Answer 5

more than one codon for each amino acid, 64 combinations- limiting the damage of mutations as although bases change, still codes for same amino acid

Question 6

what does universal code mean?

Answer 6

same triplets code for the same amino acids regardless of the species - makes genetic engineering possible

Question 7

what does non-overlapping mean?

Answer 7

codons are read ‘one by one’ - means if mutation occurs, one only codon affected

Question 8

what is a codon?

Answer 8

triplet of bases that code for one amino acid - some are stop codons in which indicate that the polypeptide is complete, some are start codons

Question 9

what is a gene?

Answer 9

section of DNA that codes for the amino acid sequence of a polypeptide and a functional RNA molecule

Question 10

where are genes found?

Answer 10

found in a fixed position on a chromosome called the locus

Question 11

how long is DNA?

Answer 11

approx 3 billion base pairs long

Question 12

features of mRNA - strand, size, shape, sugar, bases, where, quantity,
chemical stability

Answer 12

• single stranded
• short
• linear
• ribose sugar
• adenine, uracil, cytosine, guanine
• found in nucleus + cytoplasm
• More where protein synthesis occurs
• short-lived (unstable)

Question 13

features of tRNA - strand, size, shape, sugar, bases, where, quantity,
chemical stability

Answer 13

• single stranded
• short
• clover leaf shape
• ribose sugar
• adenine, thymine, cytosine, guanine
• found in cytoplasm
• re-usable, same for each cell
• long-lived (stable)

Question 14

what is mRNA?

Answer 14

a copy of a gene from DNA, leaves nucleus to carry copy of genetic code to a ribosome in the cytoplasm

Question 15

function of tRNA?

Answer 15

to attach to one of the 20 amino acids and transfer this amino acid to the ribosome to create the polypeptide chain