Genome organisation

Question 1

viral genome size

Answer 1

1776bp-1.2Mb

Question 2

prokaryotic genome size

Answer 2

112kb-13.6Mb

Question 3

eukaryotic genome size

Answer 3

2.3Mb-148.8Gb

Question 4

how is genome organised in bacteria

Answer 4

nucleoid
less packed than in eukaryotes
little non coding DNA

Question 5

positive supercoil (bacteria)

Answer 5

overrotate, add 2 turns

Question 6

negative supercoil (bacteria)

Answer 6

remove 2 turns
underrotate

Question 7

topoisomerases (P)

Answer 7

enzymes that unwind DNA

Question 8

type 1 topoisomerase (P)

Answer 8

cleave one strand of a double helix
unwinds supercoils

Question 9

type 2 topoisomerase (P)

Answer 9

cleave two strands of the double helix
introduces supercoills

Question 10

nucleoid associated proteins (prokaryotes)

Answer 10

holds supercoiled DNA together

Question 11

centromeres

Answer 11

alpha satellite DNA consisting of repetitive sequences
site of kinetochore formation (protein complex)

Question 12

telomeres

Answer 12

repetitive DNA sequences at chromosome ends
5’-TTAGG-3’ in humans
Protect chromosomes from degradation and fusion by binding to proteins to make a structure called sheltrin

Question 13

evolution of mitochondria

Answer 13

anaerobic eukaryote engulfed aerobic eubacterium/proteobacterium
symbiotic relationship
developed into mitochondria

Question 14

evolution of chloroplasts

Answer 14

ancestral eukaryotic cell, protist, engulfed cyanobacteria

Question 15

how are mitochondrial genes organised

Answer 15

A single cell will contain multiple mitochondria
A single mitochondria can contain several copies of the genome
mtDNA is circular
Mitochondria divide independently from the cell cycle
Segregate randomly among daughter cells during cell division
single promoter per strand
no untranslated areas