genetics and variation Flashcards
what does DNA stand for
deoxyribonucleic acid
what is DNA
two strands coiled to make a double helix shape
what is a molecule of DNA made up of
two strands of molecules called nucleotides
- each one contains a sugar molecule , a phosphate group and a base
atcg
A - adenine
T - thymine
G - guanine
C - cytosine
pairs of atcg
A-T
T-A
G-C
C-G
what is a gene (section of a molecule
section of a molecule of DNA that codes for a specific protein
what happens when a cell divides by mytosis
it replicates
what is a genome
entire DNA of an organism
what is mutation (change
a change in the DNA of a cell (wrong nucleotide is used) so wrong protein
dk
chromosomes contain genes
each gene contains one characteristic (codes for protein)
the genes are made up of DNA
chromosomes
46 chromosomes in human body (23 pairs)
xx= female xy=male
DNA
double hellix, spiral, polymer, coiled
what is a karyotype
all chromosomes together
what are alleles
alternative forms of the same gene
eg attached earlobe, non-attached
genotype
combination of alleles present
- homozygous - BB or bb - same alleles/genes
- heterozygous - Bb - different
