question

binary fission

answer

bacterial cell division; asexual reproduction of prokaryotes, and uses no mitosis

question

describe the process of binary fission

answer

circular DNA and organelles replicate, the copies migrate to opposite sides of the elongating cell, and the cell splits in 2, forming two identical cells

question

what are the roles of cell division

answer

reproduction, growth, and repair

question

Remember, in all organisms, cell division must distribute

answer

identical genetic material (an exact copy of the genome) into 2 daughter cells

question

genome

answer

the cell's hereditary endowment of DNA; it is usually packaged into chromosomes for manageability

question

chromosomes

answer

made of DNA and histone protein complex called chromatin; during cell division, the chromatin becomes highly condensed into the chromosomes

question

what chromosome structure

answer

at cell division, each chromosome has been duplicated during interphase; the duplicated chromosome consists of 2 sister chromatids

question

centromere

answer

the point where 2 sister chromatids are connected

question

what is the goal of cell division

answer

to create 2 identical daughter cells by splitting all the sister chromatids and giving one copy of each to each new cell

question

what are the 2 parts of the cell cycle

answer

interphase and mitotic phase (M)

question

interphase

answer

90% of the cell cycle; when the cell grows and duplicates

question

mitotic phase (M)

answer

when the chromosomes split into separate cells; this includes cytokinesis

question

what are the 3 parts of interphase

answer

G1 (first gap--growth) , S (DNA synthesis--copying of the DNA), and G2 (second gap--copy and finish preparation of cell division)

question

G1

answer

cell grows and carries out regular biochemical functions

question

S

answer

when the DNA is replicated/synthesized (chromosomes are replicated)

question

G2

answer

the cell completes preparations for division

question

Mitotic phase parts

answer

mitosis (division of replicated chromosomes) and cytokinesis (division of the cell's cytoplasm)

question

mitosis-purpose

answer

to divide the 2 copies of the DNA equally; to separate the sister chromatids into separate cells

question

what are the 5 steps of mitosis

answer

prophase, prometaphase, metaphase, anaphase, and telophase--*****prophase and telophase are opposites*****

question

prophase

answer

nucleoli disappear, chromatin condenses into the chromosomes, centrioles separate to the opposite ends of the cell, and the mitotic spindle begins to form

question

prometaphase

answer

nuclear envelope dissolves and spindle fibers join with the kinetochore of the centromeres

question

kinetochores

answer

specialized regions of the centromeres where spindle microtubules attach

question

metaphase

answer

centrioles are at opposite ends of the cell, chromosomes line up on the metaphase plate, and spindle apparatus is fully developed

question

anaphase

answer

centromeres break and the duplicate chromosomes are pulled away from each other toward opposite ends of the cell and the cell elongates (stretch out horizontally); poles move slightly further

question

telophase

answer

chromosomes uncoil back to the chromatin, nuclear envelope reforms, nucleoli reappear, spindle fibers disappear, and cytokinesis usually starts

question

microtubules do what

answer

separate cytoplasm

question

microfilaments do what

answer

contract the 2 sides of cytoplasm by wrapping around and squeezing it tight

question

cytokinesis-animals

answer

cleavage furrow forms and the microfilaments contract around the cell membrane and divides the cytoplasm into 2 parts

question

cytokinesis-plants

answer

cell plate develops from golgi vesicles and a new cell wall develps around the cell plate

question

the cell cycle is regulated by

answer

a molecular control mechanism to tell cells when to divide

question

this system moves the cell through its stages through

answer

a series of checkpoints

question

at each checkpoint, signals do what

answer

they tell the cell to either keep dividing or stop

question

checkpoints

answer

a critical control point in the cell cycle

question

what are the major checkpoints

answer

G1, G2, and M phase (after metaphase, before anaphase)

question

cells must receive a

answer

"go-ahead" signal at each checkpoint before proceeding to the next phase

question

G1 checkpoint

answer

the most important checkpoint; if a cell gets the "go-ahead" signal at this checkpoint, it usually completes the whole cell cycle and divides; if it doesn't receive this signal, it enters a non-dividing phase called the G0 phase (most specialized cells are in this state); an example is nerve and cardiac muscle cells; later, if a cell needs to divide, a "go-ahead" signal is given and the cell reactivates into the M-phase

question

control of the cell cycle

answer

kinases are enzymes; they are always in a cell but only active when they are connected to a cyclin protein so they are called cyclin-dependent kinases (CdK)

question

when cyclin is connected to a CdK,

answer

it forms an activated protein complex called MPF (M-phase promoting factor)

question

specific kinases give the "go-ahead" signals at

answer

the G1 and G2 checkpoints

question

how is mitosis initiated

answer

as a specific example, cyclin molecules combine with CdK molecules producing enough molecules of MPF to pass the G2 checkpoint and initiate the events of mitosis

question

MPF

answer

the protein complex required for a cell to progress from G2 to mitosisq

question

what is the role of MPF

answer

to trigger a chain of protein kinase activations

question

how does a cell stop mitosis

answer

during anaphase, MPF switches itself off by starting a process that leads to the destruction of cyclin molecules; it activates a cyclin-degrading enzyme, which lowers the amount of cyclin in the cell; without cyclin molecules, CdK molecules become inactive bringing mitosis to a close

question

growth factors

answer

external signals that affect mitosis

question

what are examples of growth factors

answer

PDGF, density-dependent inhibition, and anchorage dependence

question

PDGD

answer

platelet-derived growth factor what stimulates cell division to heal injuries

question

normal cell division has 2 key characteristics

answer

density-dependent inhibition and anchorage dependency

question

density-dependent inhibition

answer

the process where crowded cells stop dividing; the number of cells in a area force competition for nutrients, space, and growthe factors, so when cells are crowded, they get signals to stop dividing

question

in density-dependent inhibition, when density is high

answer

there is no cell division

question

in density-dependent inhibition, when density is low,

answer

cells divide

question

anchorage dependence

answer

normal cells must be attached to a substratum like the extracellular matrix of a tissue to divide; prevent cells from dividing and floating off in the body

question

cancer cells

answer

don't exhibit either density dependent inhibition or anchorage dependency; the control mechanisms for cell division have failed

question

transformation

answer

the process that changes a normal cell to a cancerous one

question

tumor

answer

a mass of abnormal cells within otherwise normal tissue

question

benign tumor

answer

If the abnormal cells remain at the original site

question

malignant tumor

answer

becomes invasive enough to impair the functions of 1 or more organs; individuals who have malignant tumors have cancer

question

metastasis

answer

a condition where cells from a malignant tumor separate and enter the blood or lymph vessels spreading the cancer to other organs

question

regulation of cell divison is a balance between

answer

mitosis (making new cells) and apoptosis (cell suicide or cell death)

question

cancer can result if

answer

either process doesn't work

question

cancer results from genetic changes that affect

answer

the cell cycle control

question

oncogenes

answer

cancer-causing genes

question

proto-oncogenes

answer

genes that cause cancer and are responsible for stimulating normal cell growth (ex. RAS); they become oncogenes when a mutation occurs that causes them to overstimulate the cell cycle

question

cancer

answer

can also be caused by a mutation in a tumor suppressor gene that normally inhibits cell division

question

RAS

answer

stimulates cells and repairs damage by tagging things on or off; if it never stops, it divides and causes a tumor

question

p53 gene

answer

supresses cancer in three ways; tumor suppressor gene

question

1. It halits the cell cycle by

answer

binding to the cyclin-dependent kinases; this allows time for the DNA to be repaired before the cell division resumes

question

2. It turns on what

answer

genes directly involved in DNA repair

question

when DNA damage is too great to repair, it

answer

activates suicide genes whose products cause cell death, a process called apoptosis

question

the multi- step model of cancer development is based on the idea that

answer

cancer results from the accumulation of mutations that occur throughout life

question

the longer we live, the more

answer

mutations are accumulaed and the more likely that cancer might develop

AP Bio Ch.12: The Cell Cycle – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards