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68 Cards in this Set
- Front
- Back
What is the name for copying DNA?
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DNA replication
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What are two reasons why cells divide rather than continue to grow indefinitely?
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1. more demands the larger it becomes
2. more trouble moving nutrients and waste (diffusion) |
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What must be preserved during cell growth?
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the surface area to volume ratio
(surface area-maintain larger) (volume-maintain smaller) |
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What process might become difficult if a cell grows too large?
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diffusion
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A cell makes copies of its DNA only when the cell _________.
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divides
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What (3) determines the rate at which food and oxygen in a cell are used up and waste products removed?
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1. the cell's organelles
2. the cell's volume 3. the cell's location |
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How can you obtain a cell's ratio of surface area to volume?
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divide surface area by volume
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If a cell's surface area is 6 cm and its volume 1 cm, what is the ratio of surface area to volume?
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6:1
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As a cell grows in size, its ___________ increases much more rapidly than its __________.
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volume
surface area |
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What happens in the surface:volume ratio if volume increases more rapidly than surface area?
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the ratio decreases
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What is cell division?
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the process of a cell dividing into two new daughter cells
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How does cell division solve the problem of increasing size?
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It reduces the volume of the cell, spliting it in half. It preserves, therefore, the surface area to volume ratio.
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Before cell division, DNA is packed tightly to prevent:
1. 2. |
1. losing materials and DNA
2. damage |
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Which of these:
chromatid, chromatin, or chromosomes? DNA that is found only in cell division that is joined to specfic sister chromosomes. |
chromatid
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Which of these:
chromatid, chromatin, or chromosomes? DNA usually found mainly in the cell |
chromatin
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Which of these:
chromatid, chromatin, or chromosomes? DNA found in cell division that is tightly wound from chromatin. |
chromosomes
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What is another name for cell division?
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M phase
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In eukaryotic cells, what are the two main stages of cell division?
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mitosis and cytokinesis
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When chromosomes become visible at the beginning of cell division, what does each chromosome consist of?
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DNA, wrapped around protein
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Each pair of chromatids is attached at an area called the ____________.
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centromere
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The period of growth in between cell divisions is called ___________.
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interphase
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What is the cell cycle?
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series of events that cells go through as they grow and divide.
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Sister chromatids are _________.
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identical
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What does G1 stand for? S? G2? M?
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1st growth
synthesis 2nd growth mitosis |
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The S phase is the only time of ____________ and therefore it synthesizes ________.
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DNA replication
DNA |
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During the ______ phase of the cell cycle, the cell grows and everything cells need is doubled.
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G1
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During the ____ phase of the cell cycle, DNA replication takes place.
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S
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During the _____ phase of the cell cycle, more organelles, etc. are made if needed; acts as "check off period".
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G2
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The division of the cell nucleus during the M phase of the cell cycle is caled _________.
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mitosis
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Interphase is divided into what three phases?
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G1, S, G2
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What happens during the G1 phase of the cell cycle?
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cells increase in size and synthesize new proteins and organelles
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What happens during the S phase of the cell cycle?
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DNA replication
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What happens during the G2 phase of the cell cycle?
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prepare for mitosis by adding more organelles, etc. and checking off doubled parts.
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What are the four phases of mitosis?
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prophase, metaphase, anaphase, and telophase
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What are the two tiny structures located in the cytoplasm near the nuclear envelope at the beginning of prophase?
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centrioles
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What are centrioles made of?
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microtubules
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What is the spindle?
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a fanlike microtuble/microfilament structure that separates the chromosomes
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Which event is this (mitosis)? The chromosomes move until they form two groups near the poles of the spindle.
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anaphase
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Which event is this (mitosis)? The chromosomes become visible. The centrioles take up positions on opposite sides of the nucleus.
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prophase
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What phase is this (mitosis)? A nuclear envelope reforms around each cluster of chromosomes. The nucleolus becomes visible in each daughter nucleus.
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telophase
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Which phase is this (mitosis)? The chromosomes line up across the center of the cell.
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metaphase
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What is the center of the cell where the chromosomes line up>?
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equator
metaphase plate |
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What is cytokinesis?
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the end of telophase, the division of cytoplasm
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How does cytokinesis occur in most animal cells?
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it is drawn inward and pinched into two nearly equal parts
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What forms midway between the divided nucleus during cytokinesis in plant cells? What does this later form?
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a cell plate
new cell wall |
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What happens to cells at the edges of an injury when a cut in the skin or a break in a bone occurs?
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cells are stimulated to divide rapidly
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What cell can be made into any other cell?
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stem cells
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When cells are stimulated rapidly, they ____________.
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prevent against affection
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What happens to the rapidly dividing cells when the healing process near completion?
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the rate of cell division slows
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When cells come touch one another and tell one another not to divide, they are performing ________________.
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contact inhibition
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What do cyclins regulate?
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the cell cycle
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Cyclins regulate the cell cycle by preserving __________ and making sure that each stage is completely finished before ____________.
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order
the next one begins |
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What are internal regulators?
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proteins that respond to events inside the cell
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________ regulators direct cells to speed up or slow down the cell cycle.
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external
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________ regulators prevent the cell from entering anaphase until all its chromosomes are attached to the mitotic spindle.
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internal
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_________ regulators include growth factors.
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external
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____________ regulators prevent excessive cell growth and keep the tissue of the body from disrupting one another.
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external
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What is cancer?
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a disorder that prohibits cells from controlling growth.
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All cancers ______________.
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divide uncontrollably
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Cancer means that the process of ___________ is no longer controlled.
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cell division
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Cancer cells don't respond to signals that regulate ____________.
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cell division
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Cancer cells form masses of cells called ____________.
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tumors
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Cancer cells break loose and spread throughout the ________.
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body
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Cancer is a disease of the ____________.
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cell cycle
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begins after the chromosomal movement stops.
The identical sets of chromosomes - which are by this stage at opposite poles of the cell, uncoil and revert to the long, thin, thread-like chromatin form. A new nuclear envelope forms around each chromatin mass. Nucleoli appear. Eventually the miotic spindle breaks-up. |
telophase
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The centromeres split seperating the two members of each chromatid pair - which then move to the opposite poles of the cell: When they are seperated the chromatids are called chromosomes.
* As the chromosomes are pulled by the the microtubules during _______, they appear to be "V"-shaped because the centromeres lead the way, dragging the trailing arms of the chromosomes towards the pole/s. |
anaphase
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characterized by the "__________ plate". This is a mid-point region within the cell that is formed/defined by the centromeres of the chromatid pairs aligning along the microtubules at the centre of the miotic spindle.
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metaphase
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* Early in the stage the chromatin fibres shorten into chromosomes that are visible under a light microscope. (Each chromosome consists of a pair of identical double-stranded chromatids.)
* Later in ______, the nucleolus disappears, the nuclear envelope breaks down, and the two centrosomes begin to form the miotic spindle (which is an assembly of microtubules). * As the microtubules extend in length between the centrosomes, the centrosomes are pushed to opposite "poles" (extremes) of the cell. * Eventually, the spindle extends between two opposite poles of the cell. |
prophase
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