Test 3 Lecture Flashcards
Germ-line cells
Sex cells, produce sexually
Somatic cells
All other cells produce asexually
Mitosis
Ordinary somatic cell division- makes 2 cells
Diploid
2n 46 chromosomes
Meiosis
germlins cell division results in 4 non-identical
Haploid cells
n chromosome- 23
The First Stage of the Cell Cycle
1) Cell growth
Increase in body size during growth
The Second Stage of the Cell Cycle
2) Cell repair
The replacement of dead or worn out cells
The Third Stage of the Cell Cycle
3) Cellular reproduction
Asexual reproduction
The First Stage of Interphase
G1 – Cell growth and duplication of organelles.
The Second Stage of Interphase
S – Synthesis of DNA and DNA repair
The Third Stage of Interphase
G2 – replication of centrioles and other proteins needed for division.
The nuclear envelop is still present
G0
Cells that have temporarily or reversibly stopped dividing are said to have entered a state of pause
Prophase
a) chromosomes condense
b) centrioles migrate
c) Spindle Fiber form
Prometaphase
a) The nuclear membrane and nucleolus disappear
b) Spindle fiber make contact
Metaphase
Chromosomes align
Anaphase
a) centromeres split
b) sister chromatids are pulled apart
Telephase
a) Mitotic spindles disassemble
b) chromosomes begin to unwind
c) Nuclear envelop and nucleolus
Cytokinesis
a) Division of the cytoplasm
b) cleavage furrow forms
BRCA1 and BRCA2
Breast Cancer- tumor suppressor genes
Act as a stop sign and helps repair damaged DNA
Having a BRCA mutation results in
Cancer rates much higher,
First breast cancer 56 to 85%
Second occurrence of breast cancer 50%
Ovarian cancer up to 45%
Men with a BRCA mutation also have an increased risk for breast and prostrate cancer
Proto-oncogenes
act like an accelerator in cells
Oncogene
a mutated proto-oncogene that results in cell growth being too quick.
HER genes
a oncogene that results in about 15-20 percent of breast cancer cases
X
Chromosome given from mother
Y
Chromosome given from father
How many sets of chromosomes do a sperm and egg cell have?
only 1
What is a zygote?
diploid
True or False: all cells can divide by meiosis
false. only diploid cells can divide by meiosis
What is crossing over?
exchange of homologous parts between non-sister chromatids
How do the offspring in meiosis differ from those of mitosis?
In meiosis variation can occur- meiosis results in 4 daughter cells
How are chromosomes sorted?
they are sorted by size, position, and pattern
Polyploidy
contain more than two sets of chromosomes
usually lethal in animals
some insects
some salamanders
Advantageous in fruits- leads to sterile.
Nondisjunction
can result in Euploid (normal) Trisomy (Two) or monosomy (none)
Klinefelter syndrome
an error in meiosis XXY
Triple X syndrome
an error in meiosis XXX
Jacobs syndrome
an error in meiosis
XYY
Turner syndrome
an error in meiosis
X
Down Syndrome
A mutation of the 21st chromosome
Gregor Mendal
Principles of inheritance in hybrid plants
did most work with the pea plant
Segragation
Determined that alleles always segregate in the offspring
We now know that the chromosomes physically separate during meiosis, and this is the basis for allele segregation
Gene
– a portion of the DNA, located at a fixed place on a particular chromosome, that codes for a specific product or trait.
Allele
one alternative form of a given gene
tall and dwarf) (more than 2 can exist
Genotype
the specific allele combination for a certain gene or set of genes
ex BB
Phenotype
the outword expression of the genotype
Homozygote
an individual which contains only one allele at the allelic pair
Ex DD
Heterozygote
an individual which contains one of each member of the gene pair
for example the Dd heterozygote
Hybrid
a mixture of 2 sets of alleles (we are all hybrids)
Cross
(the mating of two individuals)
Why are calico cats almost always female?
It is a sex linked trait, can only appear in X
Monohybrid Cross
a cross between parents that differ at a single gene pair
Monohybrid
the offspring of two parents that are homozygous for alternate alleles of a gene pair
Dihybrid cross
– a cross between parents that differ at two gene pairs (usually AABB x aabb)
Dihybrid
the offspring of two parents that are homozygous for alternate alleles of two gene pairs
Ratios
For phenotypes not genotypes
Codominant
two or more alleles that do not demonstrate a dominant-recessive relationship as expected
Ex AB blood
Incompletely Dominent
heterozygous offspring will have a phenotype inbetween dominant and recessive
a red and white rose can make pink roses.
Polygenic Traits
a phenotype that is dependent on more than 1 gene
Pleiotropy/Van Der Hoev syndrome
Many different symptoms from a single mutation
Brachidactyly
The short fingers but regular sized bones thing. shows that enviornment plays a role in expression
x linked recessive
Male has only one X chromosome Recessive will show up Female has two X chromosomes Recessive can be hidden “Carrier”
Barr bodies
Females have two X chromosomes One is enough (two is often too much) Therefore, one is randomly inactivated Referred to as a Barr Body Can be seen in the nucleus
A
U
T
A
G
C
C
G
U
A (in double (m) strands.
mRNA
messenger
rRNA
ribosomal
tRNA
Transfer
where does the process of meiosis occur
from the outside of the tubules to the inside
where in the seminiferous tubular would you expect to find diploid cells
outside of tubule
where would you find haploid cells
inside of tubule
how does yeast divide
budding
how does bacteria divide
fission
how does mitosis differ in cancerous tissue
cancerous tissue has a much higher mitotic index
when is DNA duplicated in meiosis
it is synthesized in the S phase of interphase
what occurs in prophase of meiosis that doesn’t happen in mitosis
meiosis goes through prophase twice
what is a continuous variable
variable such as height and quickness which have continuously varying values
what is a dichotomous or binary variable
variable such as tongue rolling and widow’s peak which have yes or no answers
dominant alleles are represented by
an uppercase letter
in fruit flies gray body color is dominant over black body-color using the letter G to represent body-color what is the genotype of a heterozygous gray bodied fly
Gg
all of The Offspring of two gray body flies are also Gray what can you conclude about the genotypes of the parents?
they’re both homozygous dominant
some of the offspring of two gray bodied flies are black what can you conclude about the genotypes of the parents
they are both heterozygous
of the human variables observed or measured in the lab which ones are primarily under the control of a single Gene multiple genes or the environment
height and weight are multiple genes that could also be environment single Gene traits are gender and handedness
what is a codon
three bases on an mRNA strand
