Chapter 3 Book Flashcards
Mitosis
Cell division that produces daughter cells
Daughter Cells
2 cell identical to parent cell
diploid number
homologous pair of choromsomes are in it
haploid #
n 1/2 of diploid #
Gametes
reproductive cell (germ line cell)
Meiosis
division reduces # of chromosomes
sex chromosomes
chromosomes that determine sex
chromosome theory of heredity
theory that chromosomes carry genes
Cell cycle
life cycle of cells
list in order the cell cycle
In interphase Gap 1, synthesis, Gap 2 and then mitosis Prophase, Metaphase, Anaphase, Telophase
Mitosis phase
Short segment of cell cycle where cells divide
interphase
longer period of cell cycle
What happens during G1
gene expression and cell activity
What happens in S phase
DNA Replication
What happens in G0 phase
gene expression but don’t go through cell cycle and most cells die
What happens during G2
Prep for cell division
Cell lineages
identical cells descended from founder cell
What are the 2 functions of cell division?
- equally divide chromosomal material
- partitioning of the cytoplasmic contents of parent cell into daughter cell
karyokinesis
part of telophase where nuclear division occurs
cytokensis
part of telophase where cytoplasmic division occurs
Sister chromatids
identical DNA that are temporarily joined together
Prophase in mitosis
Chromosomes condense, nuclear envelope breaksdown, and chromosome centromeres and sister chromatids become visible
Centromere
specialized DNA sequence on each chromosome
Kinetochore
specialized protein complex that helps with chromosome movement.
centrosomes
pair of centrioles where microtubules form the spindle apparatus
Spindle fiber microtubules
polymers of tubulin protein subunits that elongate by addition of tubulin and shortened by removal of tubulin and come from centrosomes
What are the 3 kinds of spindle fibers
Kinetochore microtubules, nonkinetochore mircotubules, astral microtubules
aster
structure forming during cell division that contains microtubules from centrosomes
Kinetochore microtubules
in protein complex called kinetochore that assembles at the centromere of each chromatid and are responsibile for chromosome movement
Nonkinetochore microtubules
Extend to each other from the 2 polar centromsomes and overlap to help elongate and stabilize cell
astral microtubules
grow toward membrane of cell where they attach and contribute to cell stability
Metaphase in mitosis
kinetochore microtubules cause opposing forces to sister chromatids causing them to line up
metaphase plate
equator of cell where chromosomes line up
sister chromatid cohesion
protein cohesin localizes between sister chromatids and holds them together to resist pull of kinetochore microtubules
Anaphase in mitosis
sister chromatids separate and move to opposite poles
Anaphase A in mitosis
separation of sister chromatids
Anaphase B in mitosis
elongation of cell into oblong shape
disjunction
separation of sister chromatids
Telophase in mitosis
nuclear membranes reassemble around chromosomes gathers at each pole and chromosome decondensation starts but is an elongated cell
cytokinesis
separation of cell
When are the cell cycle checkpoints
G1, S, G2, and Metaphase
What does meiosis produce
haploid gametes
Interphase in meiosis
Same as mitosis
Meiosis I
homologous chromosomes separate
Meiosis II
Sister chromatids separate
What is the difference between female and male gametes
Female larger with oraganelles
Prophase I in meiosis
Homologous chromosomes pair
substages of prophase I in Meiosis
leptotene, zygotene, pachytene,diplotene, diakinesis
leptotene in prophase I
Chromosome condensation begins with meiotic spindle is formed by microtubules from centrosomes
Zygotene in prophase I
nuclear membrane breaks down and homologous chromosomes align
synapsis
alignment of homologous chromosomes
synaptonemal complex
protein bridge from synapsis which is a trilayer protein structure that maintains synapsis by binding nonsister chromatids of homologous chromosomes
nonsister chromatids
chromatids belonging to different members of homologous pair of chromosomes
pachytene in prophase
sister chromatids visually distinguished with tetrads and crossing over occurs here
recombination nodules
central element of synaptonemal complex that help with crossing over
Crossing over
genetic material between nonsister chromatids switch
what is the relationship between recombination nodules and crossover events
correlate closely
diplotene in prophase I
synaptonemal complex dissolves revealing contact points between nonsister chromatids
chiasmata
located along chromosomes where crossing over occured
diakinesis
kinetochore microtubules move chromosomes toward metaphase plate where homologs align
metaphase I in meiosis
homologous chromosomes align
anaphase I in meiosis
homologous chromosomes separate
telophase I in meiosis
nuclear membrane reforms
Why is meiosis I so important
diploid becomes haploid
pseodoautosomal regions
false autosomal segments on sex cell s to align X and Y
What happens during meiosis II
sister chromatids separate
who suggested meiosis connected with mendelian hereditary principles
walter sutton and theodor boveri
What did thomas morgan do
looked at traits of drosophila melanogaste
Wild type
most common phenotype in population
who found differences in chromosomes between males and females
Nettie Stevens
Sex linked inheritance
genes on sex chromosomes
X linked inheritance
inheritance of genes on x chromosome
What can reciprocal cross show
whether trait is sex linked or autosomal
Hemizygous which causes what
1 x chromosome for males which causes trait to be determine recessive or dominant from that 1 x allele
Calvin Bridges did what
validated the chromosome theory of heredity by doing recipocal cross which 1 in every 2000 flies had exceptional phenotype
how was exception flies explained from bridge’s experiment
exceptional females had extra X Chromosome and exceptional males had 1 X chromosome but no Y which was caused by nondisjuction
Nondisjunction
failed chromosome separation
Sex determination
genetic and biological processes that produce male and female characteristics
what is the sex of most animals identified by
chromosomal sex and phenotypic sex
chromosomal sex
presence of sex chromosome associated with male and female
phenotypic sex
internal and external morphology found in each sex
How is the sex of a fly determined
the number of chromosomes determines sex to autosomal
What makes a male fly?
XY, XYY, XO 1X:2A ratio
what makes a female fly?
XX and XXY 2X:2A ratio are females
X/A ratio
ratio of X chromosomes to autosomes pairs
What makes a mammal female or male
Whether of not Y chromosome is there
What gene is important on Y for mammal to be male.
TDF (testis-determining factor)
What does SRY do?
develops male sex phenotype
What are the 2 sets of tissues that are associated with gonadal tissue which makes what sex?
Wolffian ducts make male
mullerian ducts make fermale
Z/W system and what does this do for Z linked genes
ZZ are male and ZW are female they are reciprocal crosses produce different results that X link would
X linked recessive and how does trait show
pattern of inheritance consistant with transmission of a recessive allele on X chromosome
females 2 recessive alleles while males need 1
X linked dominant and how does this trait show
inheritance hereditary pattern dominant allele of a gene on x chromosome
females and males only need 1 alleles
Y genes pass how
father to son only
What makes x linked different from autosomal?
recessive and dominant tranmission really only for female
probability of transmission of x linked alleles is not the same for the 2 sexs
males only get on X
How can recessive X linked traits be transmitted
males with recessive allele or females that are homozygous recessive
What are some X linked recessive disorders
Color blindness, Hemophilia, Fragile X syndrome
how can X linked dominant traits show
heterozygous or homozygous dominant female
male with dominant trait
How doe fruit flys deal with extra X?
X linked genes in males is doubled relative to female X linked expression
How does roundworm deal with extra X?
Each X in females is decreased to one-half gene expression that male produces
How do Marsupials deal with extra X
paternal X is inactivated
How does Placental mammals deal with extra X
chromosome randomly inactivated
Lyon hypothesis
proposed by Mary Lyon states 1 of 2 X is randomly inactivated
Barr Body
inactive X
