2. Molecular Genetics Flashcards
Cytogenetics
study of chromosomes and karyotypes
Karyotype
set of chromosomes in cells, image of chromosomes
Chromatid
one “copy” of a chromosome, formed from chromatin
Sister chromatids
identical copies of a chromosome, two are present to form one “chromosome,” only present during meiosis/mitosis
Haploid
half of the chromosomes in a cell, 23 in gametes, do not have homologous pairs
Diploid
all of the chromosomes in a cell, 46 in human cells, have homologous pairs
p
short arm
q
long arm
Euchromatin
light spots on chromosome, more expressed
Heterochromatin
dark spots on chromosome, less expressed
Centromere
center of chromosome
Telomeres
ends of chromosomes, slowly shorten throughout life and lead to aging
Telocentric
centromere at the telomeres, not seen in humans
Acrocentric
centromere slightly below telomeres, looks like telocentric on karyotype
Submetacentric
centromere just above the center
Metacentric
centromere in the middle
Nucleotide
phosphate group, sugar base, nitrogenous base
DNA
complementary, antiparallel, double-helix
Antiparallel
one strand runs 5’-3’, other strand runs 3’-5’
Nucleosome
DNA wrapped around histones
Chromatin
stacked nucleosomes
Chromosome
DNA separated into different parts
DNA Polymerase
builds 5’-3’, so will build off of DNA strand that reads 3’-5’
Helicase
unwinds DNA
Okazaki fragment
lagging strand in DNA replication, DNA polymerase can only build one way and towards the replication fork, forming fragments
Central Dogma
DNA –> RNA –> Protein
Exons
sections of DNA that get expressed in mRNA strand, code for protein
Introns
noncoding regions of DNA, get spliced out after transcription, do not code for a protein
Hybrid chromosomes
chromosomes with DNA from both parents, due to crossover during meiosis
Crossover
when homologous chromosomes overlap and exchange DNA, results in genetic diversity
Linkage maps
can determine which traits don’t follow law of independent assortment
