chapter 8 Flashcards
asexual reproduction
reproduction without sex ; parent cells divides only once to produce 2 genetically identical daughter daughter cells or offspring
How do prokaryotic cells reproduce
bacteria and arches reproduce asexually binary fission
binary fission
dividing in half
two daughter cells in prokaryotic cells
are genetically identical to each other and to the parent cell; each with 1 chromosome
all cells in our body except egg and sperm cells are called
somatic cells(body)
how are somatic cells produced
asexually by mitosis
what does mitosis allow us to do
allows us to grow and to replace damaged or worn out somatic cells
what are egg and sperm cells called
gametes or germ cells produced by meiosis
how are eukaryotic cells reproduced
by completing the cell cycle
mitotic phase consists of
cytokinesis, mitosis
G1 (first gap)
cells grow but doesnt divide
go=resting phase
S (DNA synthesis phase)
cell duplicates its dan and chromosomes; duplication of centrosomes begins
mitosis
nucleus divides
(PPMAT)
- prophase
- prometaphase
- metaphase
- anaphase
- telophase
cytokinesis
cytoplasm divides
during mitosis how many many chromosomes of parent cells are their
46 chromosomes of parent skin cells
2 daughter cells; each with 46 chromosomes
what doesnt change in mitosis
in mitosis the number of chromosomes doesnt change between the parent and each daughter cell
what do cells look like in late interphase(G20
2 centrosomes- regions where microtubules grow out from each centrosome contains-2centrioles made of microtubules
nuclear envelope is intact
chromosomes are loosely packed(decondensed)
each chromosome consists of 2 identical sister chromatids that are held together by centromere
what happenes to cells during prophase
first phase of mitosis
nuclear envelope is still present; 4 chromosomes, 8 chromatids
chromosomes are tightly packed(condensed)
two centrosomes are still present
mitotic spindle begins to form
what happens during prometaphase
second phase of mitosis
centrosomes moved to opposite poles of the cell
chromosomes are tightly packed
NUCLEAR ENVELOPE BREAKS APART
some spindle microtubules bind to kinetochores(proteins) of all chromatids
what happens during metaphase
third phase of mitosis
two centrosomes are still present
mitotic spindle brings all chromosomes to the middle of the cell
chromosomes align on the metaphase plate
kinetochores of sister chromatids are facing the opposite poles of the spindle
metaphase plate
imaginary line in the middle of the cell
meiosis
when parent cells go through 2 rounds of cell division to produce 4 daughter cells, which are genetically different from each other
1st set of chromosomes
haploid gametes”germ” cells
n=23
number of chromosomes found in ovaries and testies
2n=46 chromosomes
n=23 egg cells
n=23 sperm cells
multicellular diploid
2n=46
mitosis
somatic cells; produces 2 genetically identical daughter cells through 1 round of cell division
meiosis
egg and sperm
chromosomes are reduced, each gamet has 1/2 chromosomes as parent cell
meiosis 1
homologous chromosomes separate
meiosis 2
sister chromatids separate (daughter chromosomes)
meiosis 1 and 2 include what…
prophase, metaphase, anaphase and telophase
interphase occurs before what
meiosis
meiosis 1»>prophase 1
nuclear envelope breaks apart and mitotic spindle begins to form 6 chromosomes, 12 chromatins and 3 tetrads
prophase 1
chromosomes condense
homologous chromosomes pair up(synapsis) and form tetrads
whats phase only has tetrads
only occur during prophase 1
where does crossing over occur
maternal chromosomes (mom) paternal chromosome(dad) 2 maternal sister chromatids 2 paternal sister chromatids =identical 2 maternal sister chromatids=identical
homologous chromosomes
maternal chromatid 1 and paternal chromatid 1 = non-identical
characteristics of homologous chromosomes
are the same size, same genes and loci(position of genes on the chromosomes) but not necessarily the same version of the genes (non-sister)
crossing-over
the exchange of DNA between non-identical (but homologous) chromatids of homologous chromosomes
what is crossing over unique to
prophase 1
what is the site of crossing over
chiasma
what is the reason why we don’t look identical to our parents
crossing over ; also contributes to species diversity and independent assortment
recombinant chromosomes
new chromosomes are produced because of crossing over between gene 1 and gene 2
independent assortment
random alignment of maternal and paternal chromosomes on the metaphase plate (metaphase1)
what occurs during metaphase 1 in meiosis 1
tetrads align on the metaphase plate (pair of homologous chromosomes)
what occurs during anaphase 1 in meiosis 1
sister chromatids remain attached (non-identical because of crossing over
homologous chromosomes separate
what is allowed in interphase between meiosis 1 and meiosis 2
allows cell growth and centrosome duplication, but no chromosome duplication
what happens to chromosomes in meiosis 2
the number of chromosomes is reduced i half
nondisjunction
failure of homologous chromosomes or sister chromatids to seperate properly during anaphase 1 or anaphase 2
anaphase 1 during nondisjunction
nondisjunction pair of homologous chromosomes that fail to separate
aneuploid
nondisjunction gametes that have one less or one extra chromosome
what phase does aneuploid occur
anaphase 2
monosomy
monosomic human has 45 chromosomes (somatic cells)
is monosomy chromosome absent or present
when one chromosome is absent
trisomy
human has 47 chromosomes instead of 46 (somatic cells)
does trisomy have one less chromosome or an extra chromosome
extra chromosome is present
how do we know if a mistake occurred during meiosis
karyotype
karyotype
picture of all chromosomes in a single cell
each human somatic cell is what
diploid
how many pairs of chromosomes does diploid cell have
23 pairs from each parent
2n=46
what are chromosomes 1-22 called
autosomes or non sex chromosomes
what does chromosomes 1-22 determine
nothing; they dont determine the gender or the organism
what are the 23rd pair of chromosomes called
sex chromosomes; differ between female and male
human female
XX= homologous
human male
XY=non-homologous
what is human gamet(egg and sperm)
haploid
n=23
what would happen if sperm had only Y
daughter cells would never be made
karyotype analysis
(46 normal male chromosomes)
- gender of the organism
- normal or abnormal number of chromosomes
- length or size of chromosomes
trisomy or down syndrome
has 3 copies of chromosome 21
how many chromosomes does a male have in trisomy
47 chromosomes instead of 46
what is responsible for down syndrome
nondisjunction of chromosome 21
what is associated with chromosome pairs 1-22
down syndrome= AUTOSOMAL abnormalities
what chromosomes are considered normal
XYY
XXX
what syndrome is trisomy
Klinefelter syndrome is trisomy where male has 47 chromosomes in each of his somatic cells because of extra X chromosome (sterile)
does Klinefelter syndrome occur in male or female
male
how many chromosomes are found in Klinefelter syndrome
47
XXY
What syndrome is monosomy
turner syndrome
how many chromosomes are found in Turners syndrome
45 chromosomes instead of 46 due to lack of 1 X chromosome
XO
Does Turner syndrome occur in male or female
female
deletion
part of the chromosome is deleted, make sit shorter
duplication
part of the chromosome is duplicated, makes it longer
2 copies of gene 2
inversion
segment of chromosome is broken in two places, reversed and put back together
reciprocal translation
non homologous chromosomes exchange regions with each other creating two new chromosomes
what is the most common leukemia
chronic myelogenous leukemia
what does leukemia affect
cells that give rise to white blood cells (leukocytes)
reciprocal duplication in chronic myelogenous leukemia
part of the chromosomes 22 switches places with a small fragment from a tip of chromosome 9
homologous chromosomes also known as Philadelphia chromosomes
chromsome 22= very short
chromosome 9=long
tumor
mass of abnormally dividing cells, exhibiting uncontrolled cell division (mitosis)
benign tumor
non-cancerous
well defined edges; tumor divides but does not separate
malignant tumor
cancerous; edges are no longer well defines
invades surrounding tissues
metastasis tumor
cancerous
tumor uses blood and lymphatic vessels to invade other body parts
anaphase
4th phase of mitosis
sister chromatids separate from each other and are no longer called sister chromatid they are now called daughter chromosomes
spindle microtubules attached to the kinetochores gets shorter allowing daughter chromosomes to move to the opposite end of the cells
telophase
5th phase of mitosis
2 centrosomes are still present
2 nuclear envelope reforms around each set of 2 chromosomes
chromosomes uncoil (decondensed)
during what phase does the mitotic spindle disassemble
before telephase ends
what occurs during cytokinesis
cleavage furrow
is cleavage furrow found in plant or animal cell
animal cell
cleavage furrow forms outside or inside the cell
forms outside the cell due to the formation of contacting rings or microfilaments
contracting rings or microfilaments that occur in cleavage furrow happen inside or outside the cell
inside the cell (actin filaments)
what does contracting filaments cause cleavage furrow do to daughter cells
deepen and split parent cells into 2 daughter cells
2 daughter cells are genetically identical to each other and to the parent cell
what forms in plant cell during cytokinesis
cell wall or cell plate
what is produced during cell plate
2 daughter cells are produced when cell plate moves outward to connect with plasma membrane
cell plate
new cell wall that forms in the middle of the dividing plant cell
vesicles containing cellular material gathered in the middle of the cell and they form together to form cell plate
growth factors
proteins that stimulate some cells to divide (mitogens) and cells to grow (to get bigger)
what would happen if their were no growth factors
cells would not divide
anchorage dependence of growth
cells must be in contact with a solid surface to divide
density dependent inhabitation
cells that are touched on all sides stop dividing
relay proteins
relay the signals from the cell surface to the cells control system
control systems
includes molecules that trigger and coordinate key events in the cells
G Checkpoint or R
found at the end of G phase, makes sure the cell is growing and DNA is not damaged
G2 checkpoint
found at the end of the G2 phase makes sure that the cell has duplicated its DNA and centrosomes
M checkpoint
found during mitosis of M phase; makes sure that all chromosomes are aligned on the metaphase plate
what is the mating between 2 organisms which are similar in everything but 1 character
monohybrid cross
what do we have 2 versions of for each character encoded by a gene
alleles: one paternal and one maternal
homozygous dominant
the same two dominant alleles
PP
Homozygous recessive
the same to recessive alleles
Pp
heterozygous
one dominant and one recessive
Pp
In pea plants purple trait is dominant
trait that shows up in every generation of the family
white trait is recessive meaning
trait that skips 1 or more generations
what are examples of genotypes
homozygous recessive, homozygous dominant and heterozygous
what is the make up of organism
genotype
what does genotype tell us about?
genes or alleles
what is the physical appearance or something we can see or observe
phenotype
homozygous dominant
know how to figure out gametes
P generation (true breeding parents)
what produces purple flowers
homozygous dominant and heterozygous
what produces white flowers
homozygous recessive
what are examples of phenotypes
purple flowers and white flowers
Punnet square
way to determine the probability or chance of seeing particular trait in offspring
what is a family tree that shows the inheritance of a trait in a family through multiple generations
pedigree
incomplete dominance
heterozygous genotype has a phenotype that is intermediate between phenotypes of the two homozygotes
In snap dragons dominant allele for red flowers is what?
is NOT truly dominant because it can’t mask the recessive allele for white flowers from being seen in heterozygous
dominant alleles for purple flowers
shows up in all generations
recessive allele for white flowers
skips one or more generation
PP
homozygous for the dominant allele
aa
homozygous for the recessive allele
Bb
heterozygous with one dominant and one recessive
traits that are encoded by the genes that are located close to each other are more than likely to be what?
to be inherited together than those encoded by the genes located far apart
what is used to determine whether unknown genotype is homozygous dominant or heterozygous
testcross
test cross definition
cross between an organism of unknown genotype for a particular characteristic and organism who is homozygous recessive
traits that are most seen in nature and not necessarily specified by dominant allele
wild type trait
what can be dominant or recessive in humans
autosomal disorders
pleiotropy
single gene affects several phenotypic characteristic
polygenic inheritance
many genes control a single phenotypic character
examples of phenotypic characteristics
eye color, skin color and height
what determines the sex of offspring
in humans its Y CHROMOSOME
X-linked genes
found on the x chromosomes
sex linked genes are found on what chromosomes
sex chromosomes
females and males
x-linked
males only
y-linked
in fruit flies what determines eye color
gene that determines eye color is located on the X-chromosome
how do male flies develop white eyes
they should inherit x-linked recessive allele (white eye allele) from their mom only
how do female flies develop white eyes
they should inherit 2x-linked recessive alleles one from each parent
why are males more likely to have x-linked disorders than females
because they have only 1x chromosome, while females have 2x chromosomes
DNA nucleotide or deoxynuclotide
without oxygen
nitrogenous base, phosphate group, sugar deoxyribose
sugar phosphate backbone
made of sugars and phosphate groups
what are the bases in DNA
because there are different nitrogenous bases there are 4 different deoxynucleotides
bases in DNA
thymine, cytosine, adenine, guanine
what letter only has DNA
T
