drut test

information overload

the larger a cell gets, the more demands it places on its DNA. Eventaully the cells DNA cant meet the cells needs

exchange of materials

cells take in nutrients and eliminate waste through the cell membrane

the larger a cells volume, what does it need more of to function

the more materials it needs to function and the more waste it creates

a cells volume increases at a faster rate than its surface area. as a cell grows, does its surface-area-to-volume ratio get to big or to small?

its surface area to volume ratio becomes to small

the larger a cell gets, the (harder/easier) it is for enough materials to move across its cell membrane

harder

cell division

solves the information overload and material exchange problems

asexual reproduction does what 3 things

1) produces genetically identical organisms

2) occurs in many single-celled organisms and in some multicellular organisms

3) allows rapid reproduction of organisms in favorable environments

sexual reproduction does what 3 things

1) produces organisms with genetic info from both parents

2) occurs in most plants and animals and in many single-celled organisms

3) increases genetic diversity, which aids species survival in changing environments

packages of DNA called ___________ hold off a cells genetic info

chromosomes

prokaryotic chromosomes consist of a what

a single, circular strand of DNA

eukaryotic organisms are what

highly organized structures

the DNA winds around histone proteins forming what

chromatin

chromosomes make the precise separation of DNA possible during what

cell division

what is the series of events in the growth and division of a cell

the cell cycle

in the prokaryotic cell cycle, what does the cell do?

the cell grows, duplicates its DNA, and divides by pinching in the cell membrane

the eukaryotic cell cycle has 4 phases (the first 3 are referred to as the interphase), what are they?

1) in the g1 phase, the cell grows

2) in the S phase, the cell replicates its DNA

3) in the g2 phase, the cell produces organelles and materials for division

4) in the M stage, the cell divides in 2 stages-- mitosis (the division of the nucleus), and cytokinesis (the division of the cytoplasm)

the division of the nucleus, mitosis, occurs in how many stages

4 (PMAT)

(1) prophase

a cells genetic material condenses, a spindle starts to form, and the nuclear envelope breaks down

(2) metaphase

the duplicated chromosomes line up and spindle fibers connect to the centromeres

(3) anaphase

sister chromatids separate and move towards the centrioles

(4) telophase

the chromosomes begin to unwind and a nuclear envelope reforms

division of the cytoplasm differs in what 2 kind of cells

plant and animal cells

in animal cells, the cell membrane does what

the cell membrane draws in and pinches off

in plant cells what forms

a cell plate forms, followed by a new cell membrane, and finally a new cell wall forms. (hint: animal cells do not have cell walls)

cyclins

proteins that regulate the timing of the cell cycle in eukaryotic cells

apoptosis

a programmed cell death that plays a key role in the development of tissues and organs

cancer

a disorder in which cells divide uncontrollably, forming a mass of cells called a tumor

what are cancers caused by

defects in genes that regulate cell growth

what are treatments for cancer

removal of cancerous tumors, radiation, and chemotherapy

multicellular organisms produced via sexual reproduction begin life as a what

as a single cell

early cell divisions lead to the formation of a what

embryo

individual cells become specialized in both form and function through the process of what

differentiation

a fertilized egg and the first few cells in an embryo are able to form any kind of cell and tissue, such a cell is called what

totipotent

what is an embryonic stage that consists of a hollow ball of cells. these cells are able to become any type of body cell. such cells are termed what.

a blastocyst is an embryonic stage that consists of a hollow ball of cells.

such cells are termed pluripotent

unspecialized cells that can develop into differentiated cells are called what

stem cells, which are found in embryos and in adults

embryonic stem cells are are what

the pluripotent cells of an early embryo

adult stem cells are ________, which means they can produce many, but not all types of, differentiated cells

multipotent

potential benefits of stem cell research include what

the repair or replacement of damaged cells and tissues

why is research with human stem cells controversial

it involves ethical issues of life and death

Why is it necessary for cells to divide?

**Cells need to divide for your body to grow and for body tissue such as skin to continuously renew itself.**

What are the main parts of the cell cycle?

 **interphase, mitosis, and cytokinesis.**

What do the spindle fibers do during mitosis?

 **form a protein structure that divides the genetic material in a cell.**

How many chromosomes are in a human cell?

46