cailees Flashcards
what is mitosis?
mitosis is the process of cell division, after replication.
what are the stages of mitosis?
prophase (coils), metaphase(line up), anaphase(pulled apart) and telophase(separation).
what are the stages of the cells cycle?
g1- gap 1-normal life
S- synthesis stage -where dna copies itself
G2- Gap 2- normal life
M- mitosis (pmat)
what is interphase and what stages of the cell cycle are in it?
g1,s and g2 are all apart of interphase. the cell will be in its chromatin form in interphase, until… the cell divides into 2 daughter cells through mitosis.
what is meiosis ?
production of ova and sperm aka gametes (produced in gonads). meiosis begins the same way as mitosis. dna copies itself to produce chromosomes that have TWO chromatids each. chromosomes separate in Two divisions instead of one in mitosis.`
what is the sex gene for males
xy
what is the sex gene for females?
xx
how many chromosomes are there
23 pairs. 46 chromosomes.
how many autosomes are in the human body? plus what is the last pair?
22 autosomes and the 23rd pair are sex chromosomes
in meiosis how many divisions does a parent cell undertake?
2
what happens in mitotic division?
two haploid cells divide again to form four haploid daughter cells, they then develop into either sperm or eggs.
what is a diploid cell?
a cell with two copies of each chromosome (pairs) (2n)
what is a haploid gamete?
a cell with one copy of each chromosome (n) happens after meiosis (diploid > haploid)
what is a homologous chromosome?
chromosomes with genes for particular characteristics at the same location (identical pair)
process of cell division that results in gametes?
meiosis.
a cell with two full sets of chromosomes?
parent cell
a cell with one set of chromosomes, or half the number of chromosomes as the parent cell-
daughter cell
a gamete is is haploid . explain what this means
a haploid referes to a cell with one copy of each chromosome
the types of cell division used to make a puppy?
meiosis makes eggs +sperm, they connect in sexual intercourse, zygote in made, than the puppy is made by continuous mitosis
a horse has 64 chromosomes in its body, calculate how many chromosomes will be in each gamete.
32
calculate how many chromosomes will be in the cells of a eucalyptus tree where there are 11 chromosomes in a gamete
22
what is a tetrad
4 cells grouped together
what is a zygote
a fertilised cell
what is Somatic
any cell that IS NOT a sex cell
what are hetrologous cells?
two different chromosomes
what is crossing over?
occurs in prophase 1. chromosomes from each parent recombine to produce chromosomes that are a combination of both parents. produces variation between generations.
what is a dominant trait?
is one that hides or masks other trait.
when will recessive trait be evident?
only when there are no dominant traits present.
how many copies of each gene do we have?
2 copies. one from each parent.
how is the dominant gene shown?
a dominant gene is shown by two capital letters or just 1
how is a recessive gene shown?
two lowercase letters
when you show genes as a combination of letters we call it a
genotype e.g. TT or tt
phenotype is
the trait you receive from the genotype
what is allele
different forms of a gene for a particular trait
e.g.
TRAIT:widows peak
GENE: ‘W’ because a gene is given a letter to represent it
who was the first scientist to discover that traits were inherited?
Gregor Mendel
what is a autosome?
1-22 chromosomes in humans which are not sex chromosomes
genotype ratio
TT:Tt:tt 1:2:1 phenotype 3:1 tall 3 short 1
x-linked if the gene for the trait is on the…
x-chromosome
if the gene for colourblindness is found on the x-chromosome, and you mix colourblindness and a male with normal vision what would the gametes be?
c= colourblindness gene
female genotype= Xc Xc (so female gametes would all have Xc
male genotype= XcY
(so male gametes would have Xc or Y
what is a basic structure of a nucleotide?
phosphate, deoxyribose sugar, nitrogen rich base.
what are the nitrogen bases?
Adenine, thymine, guanine, cytosine
what is a chromatin?
46 lengths of chromosomes
where are genes found?
in a section of DNA
what is a gene?
a gene is a short section of DNA. genes control the your traits
what is a homozygous?
Two of the SAME gene. e.g. TT or tt you’re homozygous.
how does DNA replicate?
The DNA molecule unwinds and “unzips”. An enzyme breaks down the hydrogen bonds linking the bases. the open strands of DNA act as templates against which new nucleotides are assembled with pairs of the nitrogen bases (A T C G). The two new DNA molecules are formed, Esch consisting of one old and one new strand. these are called chromatids and are held together by the centromere.
what is the purpose of a centromere?
to hold chromatids together
what is a chromatid?
two chromosomes joined together with a centromere.
why does DNA replicate? whats its purpose.
the purpose of it is to make identical copies of each chromosome so that each daughter cell receive the full genetic code
what are the stages of meiosis in order?
PMAT (prophase 1, metaphase 1, anaphase 1, telephase 1, prophase 2, metaphase 2, anaphase 2, telephase 2. there are two divisions to make a gamete (sex cell).
if a gene is an X or Y chromosome its a?…
sex-linked (two sex linked traits joined makes XX or XY or in some cases XXY)
who creates the gender of the baby?
the male. woman can only produce girls.
why is meiosis different to mitosis
mitosis only makes more cells (i.e. to grow or repair). Meiosis starts off the same and only halves to produce a parent cell. then further on halves to make daughter cells.
