bio unit 4 slideshow-eukaryotic cell cycle

cell theory

all living organisms are made up of cells, and that cells are the basic unit of life. It also posits that all cells arise from pre-existing cells.

eukaryotic cell cycle includes

interphase and mitotic phase.

what happens when cell division is complete

there will be 2 daughter cells back in the G1 cycle

cytogenetics

the branch of genetics that studies chromosomes and their role in heredity.

ploidy

number of complete sets of chromosomes

diploid

2 complete sets of each chromosome, humans

haploid

1 of each type of chromosome, no homologous pairs, fungi and gametes in animals.

karyotype

visual representation of an individual's complete set of chromosomes arranged in pairs based on size and shape

sex chromosomes

determine the sex of an individual, typically represented as X and Y in humans.

autosomes (22)

non-sex chromosomes

alleles

different forms of a gene that can exist for a particular trait, usually found on homologous chromosomes.

down syndrome karyotype

a genetic disorder caused by an extra copy of chromosome 21

interphase includes

the G1, S, and G2 phases where the cell grows, replicates DNA, and prepares for mitosis.

G1

cell growth, preparation for cell division

G1 checkpoint

determine sif conditions are favorable for cell division and if the DNA is damaged. G1 cyclin is made in response to sufficient nutrients and growth factors.

G0

a quiescent state where cells exit the cell cycle and do not divide. (resting phase for certain cells, such as neurons and muscle cells).

S phase

DNA replication, DNA content doubles, but not chromosome number

G2

preparation of M chase

G2 checkpoint

checks for DNA damage, determines if all of the DNA is replicated, and monitors the levels of proteins needed for M phase

kinetochore

A protein structure on chromosomes where the spindle fibers attach during cell division, crucial for proper chromosome separation.

centromere

Region of a chromosome where sister chromatids are joined and where the kinetochore forms for mitosis.

chromatid

One of the two identical halves of a replicated chromosome, which is separated during cell division.

sister chromatids

Identical copies of a chromosome that are connected by a centromere and are separated during cell division.

Metaphase checkpoint

determines if all chromosomes are attached to the spindle apparatus

How is kinase activated?

through the binding of cyclins or phosphorylation

what phase is cyclin D in?

all of the phases

what phase is cyclin E in?

primarily present in the G1 phase and regulates the progression into the S phase.

what phase is cyclin A in?

primarily present in the S phase and regulates the progression from the S phase to the G2 phase.

what phase is cyclin B in?

primarily present in the G2 phase and regulates the progression from G2 phase to mitosis.

what do cyclin-CDK’s do?

promote progression through the cell cycle

what happens when a cyclin and Cdk bind and activate kinase

It initiates a phosphorylation cascade that modifies target proteins, driving the cell cycle forward.

how are cyclin-Cdk complexes activated or inactivated?

activated when cyclin binds to Cdk, whereas they are inactivated through degradation of cyclin or phosphorylation at specific sites.

how are proteins phosphorylated?

through the action of kinases that transfer phosphate groups from ATP to specific amino acids, altering the protein's function.

E2F

transcription factor that activates S phase genes

Rb-retinoblastoma

protein that inhibits E2F and regulates the cell cycle.

EGF

epidermal growth factor that stimulates cell growth and division by binding to its receptor.

P21

inhibits cyclin E/cdk complex

P53

tumor suppressor protein that regulates the cell cycle and prevents the proliferation of cells with damaged DNA.

apoptosis

the process of programmed cell death that allows the removal of damaged or unnecessary cells.

MDM2

a protein that negatively regulates the tumor suppressor p53 by targeting it for degradation, thereby controlling the p53 pathway in the cell cycle.

APC

a protein complex that regulates the cell cycle by controlling the transition from metaphase to anaphase in mitosis, ensuring proper chromosome segregation.

how is the APC activated?

by binding to Cdc20, which promotes the degradation of cyclins and securin, facilitating the transition from metaphase to anaphase.

cohesin

a protein complex that holds sister chromatids together during mitosis and meiosis, ensuring accurate segregation of chromosomes during cell division.