Unit 5 Vocabulary Flashcards
Genetic variation leads to –>
wider range of environments for the offspring to survive and adapt in
Diploid
cells have 2 sets of chromosomes
Haploid
cells have 1 set of chromosomes
Meiosis
diploid parental cell divides twice to make 4 haploid cells
Products of Meiosis
4 unique daughter cells
autosomes
all other non-sex chromosomes
In humans there are ____ PAIR/S of autosomes and ____ PAIR/S of sex chromosomes
22
1
Homologous Chromosomes
chromosomes similar in size, shape, carry the same genes
Karyotype
Condensed pairs of chromosomes displayed visually
Non-sister chromatids
chromatids not connected by a centromere but part of a homologous pair
Synapsis
homologous chromosomes line up next to each other
Synapsis Exception
XY sex chromosomes attach at the tips to go through synapsis
Phases of meiosis that introduce genetic variation into gamete formation (2) and how
Prophase 1: crossing over –> unique chromosomes
Anaphase 1: distribution of maternal + paternal homologs
Final products of mitosis
2 diploid
clone daughter cells
Final products of meiosis
4 haploid gametes
unique daughter cells
Relationship between gametes and zygotes
zygote: diploid cell formed by fusion of 2 gametes
3 sources of genetic diversity by sexual reproduction
Crossing over
Random assortment of chromosomes
random fertilization of egg by sperm
3 examples of conserved molecules
DNA
Ribosomes
Cell Membranes
3 examples of conserved processes
Cell Respiration
Photosynthesis
Cell division/signaling
Blending hypothesis
believed that traits found in offspring were a medium of both the parents traits
Alleles
different versions of a DNA sequence
Monohybrid cross
cross of two individuals with homozygous genotypes
Law of segregation
half the daughter cells receive maternal allele/s for a trait while half receive the paternal ones
Addition Rule of probability
A (A OR B)
Multiplication rule of probability
A(B AND C)
Chi-square test
If difference between observed and expected is more than the chi-critical value
reject null hypothesis
Chi-square test
If difference between observed and expected is less than the chi-critical value
fail to reject null hypothesis
Incomplete dominance
both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype.
Codominance
both alleles are expressed resulting in different phenotype
(example: red and white flower codominance –> pink flower)
Law of independent assortment
the alleles for one gene sort independently of the alleles for a different gene
Dihybrid cross
hybrid individuals differ in 2 traits coded by 2 different genes
Pedigree
Dominant traits
Every generation
Equally male and female
Pedigree
Recessive traits
Skips generations
Incomplete penetrance
when individuals code for a phenotype but fail to exhibit it
Variable expressivity
when phenotype is expressed in all individuals but different among each individual
Epistasis
when on gene modifies the expression of another gene
Linked genes
located near each other in same chromosome
Recombination
creation of new combinations of alleles in a chromosome by crossing over
Phenotypic plasticity
ability of a single genotype to produced different phenotypes in different environments
Identical twins
fertilized egg divides into two identical embryos
Fraternal twins
two eggs fertilized by different sperms
Mutation
change in DNA sequence that can alter order of amino acids that compromise the protein the DNA codes
Nondisjunction
failure of chromosomes to separate during cell division
Nondisjunction in Meiosis 1
results in gametes with an extra chromosome and gametes with missing chromosome
Nondisjunction in Meiosis 2
one set of gametes includes one with missing chromosome and one with an extra chromosome
Turner syndrome
X
Klinefelter syndrome
XXY
What trisomies do not lead to phenotypic changes
XXX and XYY
