Chapter 10 & 11 Test Flashcards
When the chromosome number is cut in half; involves two nuclear divisions and results in 4 genetically different daughter cells
Meiosis
Normal number of chromosomes in an organism
Diploid
Half of a diploid number
Haploid
Sex cells
Gametes
Production of a zygote from the joining of the sperm and egg
Fertilization
Product of fertilization of the egg by the sperm
Zygote
The pair that are similar that come from mom and dad
Homologous chromosomes (homologues)
Alternate forms of a gene; the choices you have within the genes
Alleles
Chromosomes that have been duplicated but are still attached
Sister chromatids
When the homologous chromosomes come together and line up side by side
Synopsis
Genetic recombination is also known as _____ _____
Crossing over
Exchange of genetic material between homologues during prophase 1
Genetic recombination (crossing over)
Site where the genes are exchanged; genes from mom and dad are mixed
Chiasma
Sources of genetic variability
Crossing over
Independent assortment of homologues
Random fertilization
Random as to which sperm fertilizes the egg
Random fertilization
Genetic variability is significant because
There is no variability in asexual reproduction
In sexual reproduction, it allows for a better chance of survival if the environment changes
Phases of meiosis
Meiosis 1
Interkinesis
Meiosis 2
Cytokinesis 2
Prophase 1
Chromosomes condense/become visible
Homologues line up gene to gene (synapsis)
Nuclear envelope disappears
Crossing over occurs
Metaphase 1
Paired homologues line up on the equator
Anaphase 1
One pair of homologues is each pulled toward opposite ends of the cell
Telophase 1
Pair of homologues reach the opposite ends of cells
Meiosis 1
Prophase 1
Metaphase 1
Anaphase 1
Telophase 1
Interkinesis
Cytokinesis between meiosis 1 and meiosis 2; when the rest of the cell is separated
Meiosis II (2 cells)
Prophase II
metaphase II
Anaphase II
Telophase II
Cytokinesis II ends with
4 cells instead of 2
Phases in meiosis II occur just like
Mitosis
Meiosis only occurs in _____
Gametes
Function of meiosis is to produce _____ ____
Haploid cells
Meiosis versus Mitosis
2 nuclear divisions
4 haploid daughter cells, genetically different
Produces haploid cells
VS
one nuclear division
2 diploid daughter cells, genetically identical
Growth and repair
The production of sperm
Spermatogenesis
The production of eggs
Oogenesis
Twins that are identical
Monozygotic
Twins that are fraternal
Dizygotic
Refers to the normal number of chromosomes
Euploidy
Refers to an abnormal / incorrect number of chromosomes
Aneuploidy
The failure of chromosomes to separate during meiosis
Nondisjunction
Nondisjunction where one extra chromosome is produced (2n + 1)
Trisomy
Nondisjunction where one less chromosome is produced (2n - 1)
Monosomy
Nondisjunction accounts for ___% of spontaneous abortions
50
Changes in the chromosome number
Trisomy 21
Trisomy 18 & 13
In mothers less than 30 years of age, the chances of having a Down’s syndrome child is 1 in _____
In mothers more than 48 years, chances are 1 in ___
Down’s syndrome is an example of _____ ___
3000; 9; trisomy 21
Children with _____ ___ and ____ usually don’t survive past infancy because of their bigger genes
Trisomy 18 & 13
Changes in chromosome number
Turner syndrome Klinefelter syndrome Poly-X Jacobs syndrome YO
Syndrome where the person only has one X Usually don't survive Female Short in stature Sexually undeveloped Normal intelligence Cannot reproduce Can live normal life if treated
Turner’s syndrome
Genotype for turners syndrome
XO
Genotype for Klinefelter syndrome
XXY
Klinefelter syndrome people….
Males
May show no signs of syndrome
Long arms/legs, big hands/feet
Develop more breast tissue than normal
Genotype for Poly-X
XXX
Poly-X people…
Female
Tall
Fertile but will have irregular periods
IQ is usually lower
Genotype for Jacobs syndrome
XYY
Genotype for YO
No history of anyone who has survived this
YO
Chromosome structural abnormalities
Deletion
Duplication
Inversion
Translocation
When part of a chromosome is lost
Deletion
Which chromosome structural abnormality is the worst?
Deletion
Examples of deletion
Cri du chat- when babies sound like cats (genes in chromosome 5)
Williams syndrome
What is Williams syndrome?
An example of deletion the affects the productions of elastin
One or more genes are duplicated
Duplication
If genes are ABC, they are flipped around to CBA; less harmful
Inversion
When a part of a chromosome breaks off and reattaches to a non homologue
Translocation
Example of translocation
CML-leukemia: between chromosomes 9 & 22
Particulate Theory of Inheritance
Refers to particles
Based on the existence of small hereditary units which we now call genes
Proposed law of segregation and law of independent assortment
What Mendel called genes; sequences of DNA on a chromosome that code for a trait)
Factors
Location of the gene on the chromosome
Locus
Gene will be expressed if only one allele is present
Dominant
Gene will be expressed with two alleles present
Recessive
Both the same from mom and dad
TT
tt
Homozygous
Two different alleles
Tt
Heterozygous
Genetic makeup of an individual
Genotype
Physical characteristics of a person
Phenotype
Looking at one trait
Monohybrid cross
Law of segregation
Each individual has two factors for each trait
Factors segregate during gamete formation
Each gamete contains only one factor from each pair of factors
Fertilization gives each new individual two factors for each trait
Law of independent assortment
Each pair of factors segregated independently of the other pairs
All possibly combinations of factors can occur in the gametes
Looks at two traits
Dihybrid cross
Autosomal recessive diseases
Methemoglobinemia Cystic fibrosis Albinism Galactosemia Phenylketonuria Tay-Sachs Disease Sickle Cell Disease
A build up of methemoglobin; people who have it are blue; BLUE FUGATES
Methemoglobinemia
Affects the protein that allows chloride to pass; builds up mucus in lungs
Cystic fibrosis
Lack of any pigment in the body; prone to skin cancer and cataracts
Albinism
Build up of the sugar galactose; damaging to eyes and liver; can cause mental handicap
Galactosemia
Build up of phenylketones; can damage the development of the central nervous system
Phenylketonuria
Lipid accumulation in the brain; causes mental deficiency and blindness; no one survives
Tay-Sachs Disease
Red blood cells are shaped like a boat rather than a werther’s caramel; causes damage in many places b/c of the shape
Sickle Cell Disease
People who are carries for sickle cell (Hh) can develop it if _____
Stressed
Autosomal dominant diseases
Osteogenesis imperfecta
Achondroplasia
Alzheimer’s disease
Huntington’s disease
Imperfect production of bones
Osteogenesis imperfecta
Bad cartilage growth; a form of dwarfism
AA = lethal
Only Aa and aa people survive
Achondroplasia
Causes mental deterioration, uncontrollable movements, and is fatal; symptoms don’t show until middle age
Huntington’s Disease
Protein on a cell that will cause a reaction
Antigen
_____ reacts with an antigen
Antibody
Example of multiple alleles
ABO bloodtyping
O blood type
Universal donor
AB blood type
Universal receiver
When the heterozygote fully expresses both alleles
Codominance
Example of codominance
ABO bloodtyping; both A and B are dominant over O
Positive or negative on blood types; comes from Rhesus monkey
Rh factor
Where the heterozygote has intermediate inheritance
Incomplete dominance
Examples of incomplete dominance
Red snapdragons crossed with white snapdragons = pink ones
Hypercholesterolemia = too much cholesterol in the blood
HH- high cholesterol
Hh- in between cholesterol
hh- low cholesterol
Dominant allele may not always be exhibited in the heterozygote
HH- will show it
Hh- may or may not
hh- won’t show it
EX: polydactyly = multiple fingers/toes
Incomplete penetrance
When multiple phenotypes are expressed through one gene
Pleiotropism
Mutation in one gene that affects connective tissue in your body; example of pleiotropism
Marfan syndrome
When one gene affects the expression of another
Epistasis
Example of epistasis
Make pattern baldness hiding a widows peak
Traits controlled by one gene; most traits are like this
EX: skin and eye color, height, intelligence
Polygenic
Father of genetics
Gregor Mendel
Can affect gene expression
Environmental
Genes that are on the sex chromosomes
X-Linked inheritance
X-Linked Inheritance
Y chromosome Sex linked genes X-linked recessive X-linked dominant X-inactivation
Major gene = SRY = sex determining region
If present, it triggers the development of testicles
Y chromosome
Genes on the sex chromosome but are not related to sexual characteristics
X^H X^H = female (homozygous dominant)
X^H Y = male (hemizygous)
OR
X^h Y
Sex linked genes
X linked recessive
Hemophilia
Red green color blindness
Duchenne muscular dystrophy
Blood disorder there a clotting factor is missing
Hemophilia
Disease that affects the nerves going to the muscles so they don’t develop properly
Duchenne muscular dystrophy
X linked dominant
Congenital generalized hypertrichosis
Hypophosphatemic rickets
Retinitis pigmentosa
Bigfoot hair
Congenital generalized hypertrichosis
Low blood phosphate
Causes problems with bones
Hypophosphatemic rickets
Condition of the eye that will cause partial blindness
Retinitis pigmentosa
One X is inactivated
Barr body- inactivated X
Random
Basis behind calico cats
X inactivation
Diagram showing inheritance through generations
Pedigrees
When and where does crossing over occur?
Prophase I of meiosis I at the chiasma
Homozygous recessive has two recessive _____
Alleles
Genotype of someone who has Jacobs syndrome
XYY
Difference between meiosis I and mitosis
Homologous pairs line up whereas chromosomes line up
