Studied by 25 peopleinformation 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
produces genetically identical organisms
occurs in many single-celled organisms and in some multicellular organisms
allows rapid reproduction of organisms in favorable environments
sexual reproduction does what 3 things
produces organisms with genetic info from both parents
occurs in most plants and animals and in many single-celled organisms
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?
in the g1 phase, the cell grows
in the S phase, the cell replicates its DNA
in the g2 phase, the cell produces organelles and materials for division
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
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