Unit 1 & 2 - Genetics Flashcards
Genes can
- Turn on and off
- Be decoded by ribosomes to build protein
Each cells has
Exact set of genes turned on in diff type of cell
DNA is made up of
- Adenine
- Thymine
- Cytosine
- Guanine
Nucleotide
Phosphate group, carbon sugar, nitrogenous base
Sequence
Order of nucleotides
DNA is made by
- Splitting DNA w/enzymes
- Matching other enzymes (AwT and CwG)
Gene
Segment of DNA molecule coding for certain trait
Locus
Location of gene on chromosome
Allele
One of two+ versions of genetic sequence in specific location on chromosome
Homologous
Same structure and position
Mitosis
Repairs/creates new cell & chromosome # is maintained
Meiosis
- Creates gametes w/half chromosomes for reproduction (haploid)
- Results in ova/sperm
Human Somatic Cells
- Diploid
- 23 maternal & paternal set
Homologous Chromosomes
Chromoes that code for the same genes
Sperms cells are made by
Spermatogonia in testes
Eggs are made by
oogonia in ovaries
Plants make
pollen and ovules
Interphase I
Germ cell replicates DNA (92)
Prophase I
- Homologous chromosomes link, condense to make tetrads
- Crossing over to exchange info from non-sister chromatids (genetic variation)
Metaphase I
- Microtubules move chromosomes to metaphase plate
- Random assortment (genetic variation)
Anaphase I
- Chromosomes seperate but sister chromatids stay together (46)
Prophase II
- New spindle fibres form
Metaphase II
Chrromatids line up
Anaphase II
They seperate
Telophase II
Four haploid cells w/23 chromosomes
Meiosis for Egg Cells
- Meiosis I divides to makes a 2ndary Oocyte & 1 polar body
- Meiosis II divides making 1 egg and 2nd polar body
Aneuploidy
- Too many/few chromosomes from non-disjunction
Non-disjunction
Homologous chromosomes don’t seperate
Turner Sydrome
1 x, no y
Kinefelter Syndrome
2 x, 1 y
Patau Syndrome
Trisomy of 13
Edwards Syndrome
Trisomy of 18
Deplication/deletion
Chromosomes exchange info incorrectly in cross-over by changing genetic info
Translocation
Transfer of DNA to wrong chromosome
Gene Y has
SRY gene to control testicular & sperm developement
Karyotype
Organizing chromosomes
Genetic Screening
- Taken from amniotic fluid, blood, bone marrow, placenta
1 x, no y
Turner Syndrome
2 x, 1 y
Kinefelter Syndrome
Trisomy of 13
Patau Syndrome
Trisomy of 18
Edwards Syndrome
Monohybrid
Mixing of one trait
Dihybrid
Mixing of two traits
Allele
specific form of a gene
Phenotype
Trait shown
Genotype
Actual genetic make up
Homozygous
Alleles are same
Heterozygous
Alleles are different
The Hybrid Ratios
- 3:1
- 9:3:3:1
Codominance
Expression of heterozygous alleles
Major Blood Types
- Type A, Anti B
- Type B, Anti A
- Type AB, universal recipent
- Type O, Anti A and B, universal donor
Incomplete Dominance
Heterozygous alleles blend
Sex-linked/x linked
- Recessive disorders found on X chromosomes
- Males more likely to express bc y gene doesn’t protect
Pedigree Charts
Trace inheritance of trait in family
Charles Darwin Proposed
Species branched from common ancestors so evolutionary relatedness could be used
Phylogeny
Study of evolutionary relatedness between and among species
Clade
Taxonomic group that includes single common ancestors & all descendant
Pro & Con of Phylogeny
- Pro: relatedness through genetics
- Con: Takes time & money
Ancestral Characteristic
Trait/feature from common ancestor of a clade
Law of Segregation
During gamete formation only one of the two gene copies in an organism is distributed to each gamete
Law of Independent Assortment
Segregation of 2 pairs of alleles occurs independently
Burkitt’s Lymphoma
Crossing over of 8 and 14
Sex Linked Disorders
- Hemophilia (no clots)
- RG colour blindness
- Male baldness
- Diabetes insipudus (anitduratic hormone)
- Menkes disease (kinky hair)
