Guide to the Human Genome ✓

Question 1

Basic DNA structure

Answer 1

DNA pairs in an antiparallel spiral
read in a 5’ to 3’ direction
has a deoxyribose backbone
wound around proteins called histones to form chromosomes

Question 2

DNA Replication

Answer 2

DNA can be damaged in replication
when repair mechanisms are defective, disease occurs

Question 3

Cell cycle

Answer 3

G1 to S to G2 to M
DNA synthesis happens during S phase

Question 4

Mitosis

Answer 4

One diploid cell becomes 2 identical diploid daughter cells

Question 5

Meiosis

Answer 5

One diploid cell becomes 4 haploid daughter cells

Question 6

Transcription and Translation

Answer 6

DNA transcribed into pre-mRNA
Pre-mRNA is spliced to become mRNA (introns are removed)
mRNA translated to a protein (three bases becomes one amino acid or stop codon)
Protein is modified and moved around the cell

Question 7

RNA

Answer 7

single stranded
ribose sugar backbone
U replaces T

Question 8

Sequence variation within a gene

Answer 8

changes in promoter sequence
changes in exon sequence

Question 9

two types of sequence changes in DNA between genes

Answer 9

SNPs and CVNs

Question 10

SNPs

Answer 10

single nucleotide polymorphisms
affect gene function, some effects may make you more prone to disease e.g. affecting transcription
most will however have no effect

Question 11

CVNs

Answer 11

copy number variation
extra/missing stretches of DNA due to deletions or duplications
no. of copies of a particular gene varies from one individual to the next