college biology chapet 8 test

-multicellular organisms begin life as a single cell

-humans become trillions of cells because of cellular respiration

-replaces worn out or damaged tissues

overview of cellular respiration

asexual reproduction

doesnt require a sperm or egg cell it involves a single organism producing offspring genetically identical to itself. ex)binary fission

chromosomes part in cellular reproduction

DNA is copied and passed to each daughter cell, then DNA is packaged into chromosomes which ensures proper distribution during cell division.

chromosomes at the beginning of the cell cycle

chromatin are condensed into…

46 chromosomes

humans have…

mitotic phase

sequence of stages that take place between the time a new cell has arisen to the point where it gives rise to two daughter cells

distributes duplicated nuclear contents of parent cells to daughter cells

daughter chromosomes are then separated into sister chromatids

sister chromatids joined by a centromere and each has idential DNA

duplicated chromosomes are composed of….

interphase

G1- stage right before DNA replication, cell doubles organelles, accumulates materials for DNA synthesis, makes decision to divide or not

G0- prevents cell from dividing

S- DNA synthesis

G2- follows DNA synthesis and extends to onset of mitosis, synthesizes proteins needed for division

daughter nuclei

produced by mitosis and are genetically identical to parent cells

spindle

most eukaryotic cells require to pull the sister chromatids apart

made of microtubules

centrosomes

primary microtubule organizing center

-prophase-chromosomes are condensed into pairs, nucleolus disappears and the nuclear envelope breaks down, spindle fibers begin to form

-metaphase-chromosomes line up along equatorial plate, and spindles reach out to attach, unattached spindle fibers reach all the way around and overlap themselves

-anaphase-chromosomes are pulled to opposite sides of the cell-sister chromatids—>daughter chromosomes

-telephase and cytokinesis-spindles disappear and nuclear envelope reappears are daughter chromosomes, division of the cytoplasm begins, each cell has the exact same number of chromosomes two cells are fully visible under a microscope

mitosis divided into 4 phases in an animal cell

plant-have centrosomes but lack centrioles, cell membrane forms along cell plate

animal-have centrosomes and have two centrioles, cell membrane forms through a cleavage furrow

plant vs animal cell division

-prophase-nucleolus has disappeared and sister chromatids are visible, centrosomes begin moving apart and spindles begin to form. the kinetochore of each chromatid is attached to the spindle fibers to match

-metaphase-centromeres of duplicated chromosomes are aligned at metaphase plate, kinetochore spindle fibers attached to sister chromatids comes from diff poles

-anaphase-sister chromatids part, each pole receives the same number and kind of chromosomes

-telophase-daughter cells are forming as nuclear envelope and nucleoli come back, chromosomes will be come indistinct chromatin

mitosis divided into 4 phases in plant cells

cytokinesis in animal cells

cleavage furrow forms as anaphase ends, contractile ring forms a constriction and the two cells are separated

cytokinesis in plant cells

cell wall prevents furrowing so new plasma membrane is built between daughter cells, golgi appartus forms vesicles, new membrane releases molecules that form the new cell walls

cell cycle control system

ensures stages occur in the correct order and that the cycle only continues when the previous stage is done

G1-cell is committed to divide but can enter G0 if not passed. proper growth signals must be present and DNA integrity is checked

G2-verifies DNA replication and fixes damaged DNA

M- makes sure all chromosomes are attached to spindles

CCS checkpoints

signal

molecule that simulates or inhibits an event

kinases

remove phosphate from ATP to move to other molecules

cyclins

internal signals only present during certain phases

epidermal growth factor

stimulates skin to finish healing after injury

estrogen stimulates the lining of the uterus in preparation for egg implantation

cells stop dividing when they touch bc of contact inhibition

cells divide like 70 times and then die

fun facts

telomere

repeating DNA sequence at rhe end of chromosome

cancer

uncontrolled cell division

malignant

cancerous

benign

non cancerous

proto-oncogenes

code for proteins that promote the cell cycle and are linked to apoptosis

apoptosis

programmed cell death

tumor suppressor genes

code for proteins that inhibit the cell cycle and promote apoptosis

oncogenes

mutated proto-oncogenes that cause cancer

translocations

chromosomes can break off and attach to another

carcinogenesis

developement of cancer, lack differentiation and dont contribute to body function

undergo apoptosis so they never die

cancer cells never…

surgery

chemotherapy

radiation

cancer treatments

don’t smoke

avoid sun exposure

avoid heavy drinking

healthy diet

preventatives for cancer