L1: Genetic Principles of Medicine: Nucleic Acids, Genes, and Chromosomes Flashcards
1
Q
genome
A
- the sum of genetic information for an organism
2
Q
gene
A
- a specific sequence of DNA that encodes a specific protein
3
Q
How much DNA in the human genome codes for proteins?
A
- low
- only around 1.2%
4
Q
What is non-coding DNA used for
A
- needed to control expression of genes
5
Q
Rank size of chromosome, gene, genome, and nucleotide
A
- nucleotide < gene < chromosome < genome
6
Q
chromosome
A
- a single molecule of genomic DNA
7
Q
genome of prokaryotes
A
- small, simple genomes
- circular or linear DNA molecules
8
Q
genome of eukaryotes
A
- large genomes
- lots of extra DNA
- long, linear DNA molecules
9
Q
origin of replication in prokaryotes
A
- single site of origin
10
Q
origin of replication in eukaryotes
A
- large genome and multiple sites of origins of replication
11
Q
What challenges do eukaryotes face due to their large genomes and linear chromosomes?
A
- because the genome is large, that makes it difficult to replicate
12
Q
what happens as DNA strands are separated on one side of the fork?
A
- DNA on the other side becomes supercoiled
13
Q
role of type I topoisomerase
A
- nicks one DNA strand to allow relaxation of supercoiling
- then seals the nick
14
Q
role of type II topoisomerase
A
- makes double-stranded break in one duplex of DNA
- unbroken duplex is passed through ends of break
- break is sealed and enzyme releases DNA
15
Q
template
A
- basis for instruction
16
Q
origins of replication
A
- defined sites where replication begins
17
Q
helicase
A
- unwinds DNA at fork
- present template for instruction
- breaks the Watson-Crick base pairs that form double helix