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BIOL 1406
Exam 3 Ch. 9
42
Biology
Undergraduate 1
04/15/2007

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Term
Cell Cycle
Definition
is an orderly set of stages that tale place between the time a eukaryotic cell divides and time the resulting daughter cells also divide.
(150)
Term
Interphase
Definition
stages of the cell cycle during which growth and DNA synthesis occur when the nucleus is not actively dividing
(150)
Term
Stages of Interphase
Definition
G1 - growth, S - growth and DNA replication, G2 - growth and final preperations for division, M - mitotic
(150)
Term
Chromatid
Definition
each double helix is called a chromatid
(150)
Term
Signal
Definition
is a moleccule that stimulates or inhibits a metabolic event.
(151)
Term
Growth Factor
Definition
are external signals received at the plasma membrane
(151)
Term
Cyclins
Definition
Researchers have identified a family of internalsignaling proteins called cyclins that increase and decrease as the cell cycle continues.
(151)
Term
Apoptosis
Definition
is often defined as programmed cell death becasue the cell progresses through a usual series of events that bring about its destruction.
(151)
Term
Somatic Cells and Cell Division
Definition
cell division increases and apoptosis decreases the number of somatic cells
(151)
Term
Chromatin
Definition
When a eukaryotic cell is not undergoing division, the DNA (and associated proteins) within a nuclues is a tangled mass of then threads called Chromatin
(153)
Term
Dipolid (2n) Number
Definition
includes two chromosomes of each kind
(153)
Term
Haploid (n) Number
Definition
half the diploid number, called haploid number of chromosomes, contains only one chromosome of each kind
(153)
Term
Sister Chromatids
Definition
Each chromosome now has two identical double helix molecules; each double helix is a chromatid, and the two identical chromatids are called sister chromatids.
(153)
Term
Centromere
Definition
Sister chromatids are constricted and attached to each other at a region called the centromere
(153)
Term
Centrosome
Definition
the main microtubule-organizing center of the cell, divides mitosis begins
(154)
Term
Centrioles
Definition
Each centrosome in an animal cell - but not a plany cell - contains a pair of barrel-shaped organelles called centrioles.
(154)
Term
Spindle
Definition
the centrosomes organize the mitotic spindle, which contains many fibers, each composed of a bundle of microtubules
(154)
Term
Microtubules
Definition
are hollow cylinders made up of the protein tubulin
(154)
Term
Prophase
Definition
it is apparent during prophase that nuclear division is about to occur because chromatin has condensed and the chromosomes are visible.
(154)
Term
Asters
Definition
in animal cells, an array of microtubels radiates toward the plasma membrane from the centrosomes, these structures are called asters.
(155)
Term
Prometaphase (Late Prophase)
Definition
preperations for sister chromatid seperations are evident.
(155)
Term
Metaphase
Definition
during metephase the centromeres of chromosomes are now in alignment at the center of the cell
(155)
Term
Metaphase Plate
Definition
an imaginary plane that is perpendicular and passes through this circle is called the metephase plate
(156)
Term
Anaphase
Definition
At the start of anaphase, the two sister chromatids of each duplicate chromosome seperate at the centromere, giving rise to two daughter chromosomes
(156)
Term
Telophase
Definition
during telephase the spindle disappears as new nuclear envelopes form around the duaghter chromosomes
(156)
Term
Cell Plate
Definition
is simply newly formed plasma membrane that expands outward until it reaches the old plasma membrane and fuses with this membrane
(157)
Term
Mitosis
Definition
mitosis is critical to the developement and repair of organisms
(157)
Term
Neoplasm
Definition
is an abnormal growth of cells
(159)
Term
Benign and Malignant
Definition
Benign neoplasm is not cancerous and Malignant neoplasm is cancerous
(159)
Term
Cancer
Definition
is a cellular growth disorder that results from the mutation of the genes that regulate the cell cycle.
(159)
Term
Carcinogenesis
Definition
the developement of cancer, is gradual
(159)
Term
Tumor
Definition
the abnormal cancer cells pile on top of one another and grow in mulyiple layers, forming a tumor.
(159)
Term
Metastasis
Definition
many types of cancer can undergo metastasis and spread, forming new tumors distant from the primary tumor.
(159)
Term
Angiogenesis
Definition
the formation of new blood vessels, is required to bring nutrients and oxygen to a cancerous tumor whose growth is not contained within a capsule.
(159)
Term
Proto-onocogenes
Definition
specify proteins that directly and indirectly promote the cell cycle
(160)
Term
Tumor suppressor genes
Definition
specify proteins that directly and indirectly inhibit the cell cycle.
(160)
Term
Telomeres
Definition
DNA segments called telmoreres occur at the end of chromosomes and protect them from damage.
(160)
Term
Oncogenes (cancer-causing genes)
Definition
proto-oncogenes are so called because a mutation can cause them to become oncogenes.
(160)
Term
Asexual Reproduction
Definition
Cell division in unicellular organisms, such as prokaryotes, reproduces two new individuals.
(162)
Term
Prokaryotes (bacteria and archaea)
Definition
lack nucleus and other membranous organeles found in eukaryotic cells.
(162)
Term
Nucleoid
Definition
In electron micrographs, the bacterial chromosome appears as an electron-dense, irregularly shaped region called the nucleoid
(162)
Term
Binary Fission
Definition
Prokaryotes reproduce asexually by binary fission, the process is termed binary fission because division (fission) produces two (binary) daughter cells that are identical to the original parent cell
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