bio chapter 9

2 major stages of the cell cycle

interphase and mitotic stage

bone marrow, __% divide per day so by day 57, all have divided at least once

8

DNA is normally in very long threads called

chromosomes

DNA is associated with _____ proteins

histone

before mitosis begins

chromatic condenses into visible chromosomes

histones

are proteins that help package DNA into a compact, organized structure, facilitating the efficient storage of genetic information

the complex of DNA plus histones and other structural proteins is called

chromatin

Diploid (2n) number creates

2 of each chromosomes

humans have __ different chromosomes

23

at the end of DNA replication…

each chromosomes duplicated is attached together at a single point called the centromere

during mitosis…

sister chromatids separate which is the daughter chromosome

organelle found just _____ the nucleus

outside

the organelle organizes ______

mitotic spindle

interphase

the phase where the cell prepares for mitosis by growing and replicating its DNA

what are the 3 sub phases of the interphase?

G1, S, and G2

what is the G1 phase of the interphase

the first stage of interphase. the cell doubles its organelles and grows in size. the cell accumulates raw materials for DNA synthesis

what is the S phase of the interphase

the second stage of interphase. DNA replication and synthesis of associated proteins. chromosomes enter with 1 chromatid. chromosomes leave with 2 identical sister chromatids

what is the G2 phase of the interphase

the third stage of interphase. the cell continues to grow and prepares for mitosis by producing proteins and organelles needed for cell division.

apoptosis

programmed cell death

mitotic stage

the phase of the cell cycle that includes mitosis and cytokinesis, resulting in two daughter cells

prophase

the first stage of mitosis where chromatin condenses into chromosomes, nucleolus diappears, the nuclear envelope breaks down, and spindle fibers begin to form, centrosomes move away from each other

prometaphase

stage where centromere develops two kinetochores. specialized protein complex, one attached to each sister chromatid, physically connect sister chromatids, connect sister chromatids to opposite poles of the mother cell

metaphase

the stage of mitosis where chromosomes align at the cell's equatorial plane, attached to spindle fibers at their kinetochores

metaphase plate

represents plane through which mother cell will be divided

anaphase

the stage of mitosis where sister chromatids separate and are pulled towards opposite poles of the cell by the spindle fibers. they are now called daughter chromosomes

telophase

the final stage of mitosis where 2 daughter chromosomes reach the poles, begin to de-condense, and nuclear envelopes re-form around each set of chromosomes

cytokinesis

the process where the cytoplasm of a parent cell is divided into two daughter cells, typically following mitosis

what happens with cytokinesis in plants

involves the formation of a cell plate that develops into the new cell wall, separating the two daughter cells

who is the scientist who first isolated human stem cells

James Thomson

cancer is when….

a tumor creates an abnormal growth of cells

benign

not cancerous

malignant

cancerous

lack differentiation

refers to cells that do not develop specialized functions and structures like normal cells do, often seen in cancerous tissues

have abnormal nuclei

abnormal number of chromosomes, extra copies of genes

do not undergo apoptosis

cancer cells are abnormal but fail to undergo apoptosis

what are cancer cell characteristics

lack differentiation, have abnormal nuclei, do not undergo apoptosis, form tumors, undergo metastasis, undergo angiogenesis

form tumors

contact inhibition gone

undergo metastasis

original tumor fragments create new tumors appear in other organs

undergo angiogenesis

formation of new blood vessels

who is henrietta lacks?

an African American woman whose cancer cells were harvested without her knowledge in 1951, leading to the development of the HeLa cell line, which has been vital for medical research

what is the origins of cancer?

onocogenes and tumor suppressor genes

oncogenes

promote cell cycle in various ways and promote cancer development if activated

tumor suppressor genes

inhibit cell cycle in various ways and promotes cancer development if inactivated

telomerase

enzyme that maintains length of telomeres

telomeres is the special material at the end of ____

DNA

when telomerase get too short, the cell no longer ____

divides

a prokaryotic chromosome is a _____ ring of DNA

single

binary fission

a form of asexual reproduction in prokaryotes where a single cell divides into two identical daughter cells