honors bio--chromosomes

what is another term for cell reproduction

cell division

cell division occurs in humans and other organisms at different times in their life when…

new cells are formed

what are 2 types of eukaryotes that perform cell division?

mitosis and meiosis

what type of cells does mitosis produce?

somatic or body cells

examples of mitosis

skin, heart and liver cells

mitosis is a form of ------- reproduction

asexual

what type of cells does meiosis produce?

gametes or sex cells

examples of meiosis

sperm and egg

meiosis is a form of ------- reproduction

sexual

before a cell divides, the ---- is first copied and then distributed

DNA

prokaryotes reproduce by a type of cell division called…….

binary fission

binary fission is a form of ------ reproduction that produces identical offspring

asexual

in asexual reproduction, a single parent passes exact ---------- to its offspring

copies of all of its DNA

how many stages does binary fission occur in?

2

in the first stage of binary fission, the ---- is copied, and then the cell ------

DNA, divides

in the second stage of binary fission, the prokaryote is pinched into….

2 independent cells

a ----- is a segment of DNA that codes for a ---- or RNA molecule

gene, protein

when genes are being used, the ----- is stretched out so that the information it contains can be used to direct the synthesis of proteins

DNA

a loose form of DNA is called….

chromatin

as a eukaryotic cell prepares to divide, the DNA and the proteins associated with the DNA coil up into a structure called a……

replicated chromosome

the two exact copies of DNA that make up each replicated chromosome are called….

chromotids

the two chromotids of a chromosome are attached at a point called a….

centromere

during eukaryotic reproduction, the chromotids become seperated during….

cell division

when chromotids are seperated when a eukaryotic cell reproduces, they are each placed into a new cell to ensure that each new cell will have the same ------------- as the orginal cell

genetic information

how long does it take for a prokaryotic cell to divide

20 minutes

how long does it take for a eukaryotic cell to divide

24 hours

\-------- chromosomes are chromosomes that are similar in size, shape, and genetic content

homologous

each --------- in a pair a homologous chromosomes comes from one of the two parents

homologue

the 46 chromosomes in human ------ cells are actually two sets of ---- chromosomes

somatic, 23

when a cell, such as a somatic cell, contains two sets of chromosomes, it is set to be -----. ex: 2n=46 for humans

diploid

when a cell, such as a gamete, contains one set of chromosomes, it is said to be -------. ex: n=23 for humans

haploid

the fusion of 2 haploid gametes, is a process called ------- and forms a dipoid ------

fertilization, zygote

a fertilized egg cell is a….

zygote

\------- are chromosomes that are not directly involved in determining the sex (gender) of an individual. they are chromosome numbers ---- in a karyotype

autosomes, 1-22

the -----------, one of the 23 pair of chromosomes in humans, contain genes that will determine the sex of an individual

sex chromosomes

in humans and many other organisms, the two sex chromosomes are referred to as the -- and -- chromosomes

x,y

xx= -----

girl

xy= -----

boy

x= -----

girl with boy like features

y= -----

die

xxy= -----

boy with girl characteristics

humans with more than 2 copies of a ------, a condition called trisomy, will not develop properly

chromosome

another name for trisomy 21

down’s syndrome

abnormalities in chromosome number can be detected by analyzing a --------, a photo of the chromosome in a dividing cell that shows the chromosomes arranged by size

karyotype

changes in an organism’s chromosome structure are called….

mutations

breakage of a chromosome can lead to - types of mutations

4

what are the types of mutations?

deletion, duplication, inversion, translocation

\-------- removes a chromosomal segment

deletion mutation

\------- repeats a segment

duplication mutation

\--------- reverses a segment within

inversion mutation

\-------moves a segment from one chromosome to another nonhomologous one

translocation mutation

the ------- is a repeating sequence of cellular growth and division during the life of an organism

cell cycle

a cell spends 90 percent of its time in the first three phases of the cycle which are collectively called -----------. cells such as mature nerves and muscles will never go through -------, but stay in ---

interphase, mitosis, G0

how many phases are in the cell cycle?

5

what stage of the cell cycle does a cell grow rapidly and carries out its routine functions

stage 1, first growth, G1

what stage of the cell cycle does a cell’s DNA and centrioles are copied

stage 2, synthesis, S

what stage of the cell cycle are preparations made for the nucleus to divide, organelles are duplicated and microtubules are formed for the spindle apparatus

stage 3, second growth, G2

what stage of the cell cycle does the nucleus of a cell is divided into two identical nuclei, includes 4 phases of its own

stage 4, mitosis

what stage of the cell cycle does division of the cytoplasm occur, creating 2 identical cells

stage 5, cytokinesis

the cell cycle has key checkpoints at which -------------- from the cell can trigger the next phase of the cell cycle.

feedback signals

other feedback signals can delay the next phase to allow for completion of the ------------

current phase

control of the cell cycle occurs at - principle checkpoints

3

this checkpoint makes the decision of whether the cell will divide

cell growth, G1

DNA replication is checked at this point by DNA repair enzymes

DNA synthesis, G2

this checkpoint triggers the exit from mitosis

mitosis checkpoint

if a cell fails a checkpoint, it may kill itself via…

apoptosis

certain ----- contain the information necessary to make the proteins that regulate cell growth and division.

genes

what is the uncontrolled growth of cells

cancer

during -------, the chromatids on each chromosome are physically moved to opposite sides of the dividing cell with the help of the --------

mitosis, spindle

\------- are cell structures made up of both centrioles (animals only) and individual microtubule fibers that are involved in moving chromosomes during cell division. ------- fibers attach directly to the chromosome whereas nonkinetochore fibers overlap at the ------ from opposite poles.

spindles, kinetochore, equator

when a cell enters the ------- phase, the centriole pairs start to seperate, moving toward opposite poles of the cell.

mitotic

as the centrioles move apart, the ------ begins to form

spindle

plant cells lack……

centrioles

the chromatids are moved to each ----- of the cell in a manner similar to bringing in a fish with a fishing rod and reel.

pole

when the microtubule “fishing line” is “reeled in,” the -------- are dragged to opposite poles

chromatids

as soon as the chromatids seperate from eachother they are called ----------

chromosomes

what are the steps of mitosis?

prophase, metaphase, anaphase, telophase

in prophase the nuclear envelope and ------ dissolve, chromotin coils up into visible replicated chromosomes under a scope, causing a ------ to form

nucleolus, spindle

in prophase chromosomes move to the center of the cell and line up along the -------- due to kinetochore fibers. ----- are at the poles. this is the longest stage

equator, asters

in anaphase centromeres divide and ------- part toward opposite poles via kinetochore fibers. the cell shape ------ caused by non-kinetochore fibers. this is the fastest stage

chromatids, elongates

in telephase a nuclear ------ forms around the chromosomes at each pole that uncoil back into chromotin. nucleoli reappear in each new nucleus. spindle breaks down. ---- forms

envelope, cleavage

the purpose of ----- is growth, repair, and routine maintenance

mitosis

as mitosis ends, ------- begins

cytokinesis

during cytokinesis, the ----- of the cell is divided in half, and the cell membrane grows to enclose each cell, forming two seperate cells as a result

cytoplasm

the end result of mitosis and cytokinesis is two genetically ------ cells where only one cell existed before

identical