mitosis and asexual reproduction

cells need to be…

small

in order to stay alive, cells must be able to transport materials (food, oxygen, wastes) across the…

cell membrane

as a cell INCREASES in size, its volume…

increases faster

in the case of a cell’s surface to volume ratio becoming too small, cells must ___ or ___!

divide or die

once a cell reaches a certain size, the _____ of the cell membrane is too ____ to meet the transport needs of the cell contents.

surface area, small

the only way for multicellular organisms to increase in _________ is to increase the number of ____

size, cells

even when multicellular organisms stop growing, their cells must be_____________ as they die or become damaged

replaced

certain organisms can reproduce by forming exact copies of themselves. this form of reproduction is called…

asexual reproduction

asexual reproduction involves only ____ parent

one

chromosomes are composed mainly of…

DNA

each nucleus contains…

chromosomes

the nucleus of a cell controls its…

activities and characteristics

DNA contains…

hereditary information

DNA consists of long chains called…

nucleotides

chromosomes are long, twisting strands of…

DNA

the two identical strands are called…

chromatids

chromatids are joined by a…

centromere

in order for non-dividing cells to conduct their day-to day activities, the chromosomes must be ____ and the DNA double helices must be ____ to expose the nitrogenous bases.  

unwound, untwisted

in the state of the unbinding of chromosomes and DNA strands, the individual chromosomes ____ be seen under a microscope.

cannot

what can be seen under a microscope is a mass of threadlike genetic material called __________________

chromatin

when it is time for a cell to divide, its chromatin begins to coil up, each strand becoming…

thicker and shorter

all organisms have a ____ set of chromosomes: ONE SET FROM EACH PARENT

double

the total number of chromosomes found in the nuclei of an organism ( the double set) is called the…

diploid number

the diploid number is represented by the symbol…

2n

the diploid chromosome number for humans is…

46

all ____________________cells of an organism contain the diploid number of chromosomes. 

somatic (body)

when organisms reproduce sexually, genetic information from two different parents must be…

combined

sperm and egg cells are also called…

gametes

in order to maintain a constant chromosome number from one generation to the next, gametes must contain only a ____ set of chromosomes or ____ the number of chromosomes of body cells.

single, half

the half number of chromosomes is called the…

haploid

haploid is represented by the symbol…

n

the haploid chromosome number for human gametes is ______

23

when a sperm cell fertilizes an egg cell, the resulting offspring contains ____ set of genetic information from each parent  (a double set)

one

mitosis refers to the process of duplicating and dividing the _____

nucleus

cytokinesis refers to the process of dividing the ___________

cytoplasm

interphase refers to the time between…

cell division

a cell spends most of its time in…

interphase

a cell _____ during interphase

grows in size

what are the building blocks (monomers) of nucleic acids such as DNA?

nucleotides

3 reasons a cell needs to divide

growth, repair, reproduction

humans have __ chromosomes

46

process of dividing the nucleus

mitosis

the cytoplasm separates to form two new cells (of approximately equal size) called…

daughter cells

in animal cells, cytokinesis occurs by constriction (pinching) of the cell membrane in the MIDDLE of the cell  called _________________

cleavage

in plant cells, a dividing wall _______________ begins to grow from the center outward at the middle (equator) of the cell. 

cell plate

cell plate becomes

cell wall

every time a cell undergoes mitosis (and cytokinesis), two ______________ daughter cells result

identical

have the same number and kind of chromosomes

identical cells

multicellular organisms can __________ by increasing the number of cells in their bodies

grow

multicellular organisms can ___ damaged cells

replace

some organisms can ___ to form an identical offspring

replicate

if a human body cell divides by mitosis, how many chromosomes will the two daughter cells have?

46

red blood cells must divide…

quickly

____ new red blood cells are made each second in the bone marrow.

2.5 million

bone cells divide…

slowly

skin cells’ normal cycle is __ hours

20

nerve cells can divide but do not go through division once they have reached _____ (70-100 yrs)

maturity

liver cells regenerate every ___ days

150

liver cells can ______ themselves

repair

if conditions of the body change, cells may have to change their rate of division to maintain ___________________

homeostasis

liver cells can remove their lobes for…

transplant

the cell cycle determines the rate of _____________________

cell division

each cell contains specific _____

genes

if the body loses control of the cell cycle, it may result in the development of…

cancer

a group of proteins- regulate the timing of the cell cycle in eukaryotic cells.

cyclins

_____ control the length of each stage of the cell cycle

cancer results from ______ cell division

uncontrolled

what tumor invades surrounding tissues?

benign tumor

what tumor spreads into other tissues and can interfere with organ function?

malignant tumor

sexual reproduction requires __ parents

2

(splitting in two) asexual reproduction in single celled organisms ( bacteria and protists)

binary fission

whole plant or part of the plant reproduces through ___________

mitosis

regeneration in animals is the growth or regrowth of an animal from a  _____ (think star fish)

part

a new, small individual grows out of the side of the parent.  The bud breaks free to live on its own. 

budding

in binary fission, cytoplasm divides…

equally

in budding, cytoplasm divides…

unequally

spores are surrounded by…

a thick, hard shell

when spores land in favorable conditions, they ____ (sprout) and grow into offspring that are identical to the parent. 

germinate

vegetative propagation is ______ reproduction involving the plant organs of roots, stems, and leaves (vegetative structures).

asexual

undifferentiated cells divide by…

mitosis

programmed cell death

apoptosis