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Biology Chapter 10 & 11 Study Guide

Terms in this set (60)

The rate at which materials enter and leave through the cell membrane depends on the cell's...?
Surface area
The process of cell division results in...
Two identical daughter cells
Sister chromatids are attached to each other at an area called the...
Centromere
If a cell has 12 chromosomes, how many chromosomes will each of its daughter cells have after mitosis?
12
At the beginning of cell division, a chromosomes consists of two...
Chromatids
The phase of mitosis during which chromosomes become visible and the centrioles separate from one another is...
Prophase
The timing of the cell cycle is eukaryotic cells is believed to be controlled by a group of closely related proteins known as...
Cyclins
In the cell cycle, external regulators direct cells to...
Speed up or slow down the cell cycle
Uncontrolled cell division occurs in...
Cancer
Explain how a cell's DNA can limit the cell's size.
When a cell is small, the information stored in its DNA is able to meet all of the cell's needs. But if a cell were to grow without limit, an "information crisis" would occur.
Describe what is meant by cell volume.
the amount of material inside the cell
Describe what is meant by cell surface area.
The total area of the cell's membrane
Describe what is meant by ratio of surface area to volume.
The surface area divided by the volume
How is a cell's potential growth affected by its ratio of surface area to volume?
A cell's ratio of surface area to volume decreases as it grows larger. This means that the area available for diffusion also decreases. Thus, if a cell grows too large, it is unable to take in all needed materials and expel all its wastes. These problems impose limits on the growth of the cell.
Describe how a cell's chromosomes change as a cell prepares to divide.
Well before cell division, each chromosome is replicated. At the beginning of cell division, each chromosome consists of two identical sister chromatids.
What is the relationship between interphase and cell division?
Together, interphase and cell division make up the cell cycle.
Summarize what happens during interphase.
A cell increases in size, synthesizes new proteins and organelles, replicates its chromosomes, and prepares for cell division by producing needed spindle proteins.
How does the number of chromosomes in the two new cells compare with the number in the original cell at the end of cell division?
The number of chromosomes in each of the two cells equals the number in the original cell.
Summarize what happens during the cell cycle.
A cell grows, prepares for division, and divides to form two daughter cells, each of which then begins the cycle again.
Describe the role of cyclins in the cell cycle.
they regulate the timing of the cell cycle in eukaryotic cells.
Why is it important that cell growth in a multi-cellular organism be regulated so carefully?
The consequences of uncontrolled cell growth are severe, as in cancer, for example.
How do cancer cells differ from noncancerous cells?
How are they similar?
Cancer cells do not respond to the signals that regulate the growth of most cells. As a result, they form masses of cells called tumors that can damage the surrounding tissues
Homologous chromosomes line up in the center of the cell
metaphase I
Spindle fibers pull the homologous pairs to the ends of the cell
Anaphase I
Four Hapliod daughter cells form
Telophase II
Cells undergo a round of DNA replication
Interphase
Sister chromatids separate from each other
Anaphase II
Two hapliod daughter cells form
Telophase I
Spindle fibers attach to the homologous chromosome pairs
Prophase I
Individual chromatids move to each end of the cell
Anaphase II
Crossing-over (if any) occurs
Prophase II
What are the number and type of cells that result from Meiosis and Mitosis
Mitosis produces 2 identical daughter cells that are identical to the mother cell, They are called somatic cells. Meiosis produces 4 hapliod cells that are different from each other and the mother cell, They are called gamtes
Asexual reproduction
A type of reproduction involving only one parent that produces genetically identical offspring.
Asters
Clusters of microtubules radiating out from the poles in dividing cells. They are present in animal cells, but not in the cells of flowering plants and most gymnosperms.
Cell cycle
Cyclic series of events in the life of a dividing eukaryotic cell; consists of stages of interphase, mitosis and cytokinesis.
Cell plate
The structure that forms during cytokinesis in plants, separating the two daughter cells produced by mitosis.
Centromere
Specialized constricted region of a chromatid; contains the kinetochore. In cells at prophase and metaphase, sister chromatids are joined in the vicinity of their centromeres.
Chromatid
One of the two identical halves of a duplicated chromosome, the two chromatids that make up a chromosome are referred to as sister chromatids.
Chromatin
The complex of DNA, proteins and some RNA that makes up eukaryotic chromosomes.
Chromosomes
Structures in the cell nucleus, composed of chromatin and containing thegenes. The chromosomes become visible with the microscope as distinct structures when
the cell divides.
Clone
- A population of cells descended by mitotic division from a single ancestral cell,
or a population of genetically identical organisms asexually propagated from a single
individual.
Crossing Over
The breaking and rejoining of homologous (nonsister) chromatids during early meiotic prophase I, resulting in an exchange of genetic material.
Cytokinesis
Stage of cell division in which the cytoplasm is divided to form two daughter cells.
Diploid
The condition of having two sets of chromosomes per nucleus.
Feritlization
Fusion of n gametes; results in the formation of a 2n zygote.
Gamete
A sex cell; in plants and animals, an egg or sperm. In sexual reproduction, the union of gametes results in the formation of a zygote. The chromosome number of a gamete is designated n.
Hapliod
- The condition of having one set of chromosomes per nucleus.
Interphase
Stage of the cell cycle between successive mitotic divisions; Its subdivisions are the G1 (first gap), S (DNA synthesis) and G2 (second gap) phases
Karyotype
- The chromosomal constitution of an individual. Representations of the karyotype are generally prepared by photographing the chromosomes and arranging the homologous pairs according to size, centromere position and pattern of bands.
Meiosis
Process in which a 2n cell undergoes two successive nuclear divisions (meiosis
I and meiosis II), potentially producing four n nuclei; leads to the formation of gametes
in animals and spores in plants.
Metaphase
The stage of mitosis, and of meiosis I and II, in which the chromosomes lineup on the equatorial plane of the cell. Occurs after prophase and before anaphase.
Mitosis
Division of the cell nucleus, resulting in two daughter nuclei, each with the same number of chromosomes as the parent nucleus. Mitosis consists of four phases: prophase, metaphase, anaphase and telophase
Prophase
The first stage of mitosis, and of meiosis I and II. During prophase the chromosomes become visible as distinct structures, the nuclear envelope breaks down, and a spindle forms (Meiotic prophase I is more complex, and includes synapsis of homologous chromosomes and crossing over).
S phase
Stage in interphase of the cell cycle during which DNA and other chromosomal constituents are synthesized.
Sexual reproduction
- Type of reproduction in which two gametes (usually, but not necessarily, contributed by two different parents) fuse to form a zygote.
Spindle
- Structure consisting mainly of microtubules that provides the framework for chromosome movement during cell division.
Synapis
The process of physical association of homologous chromosomes during prophase I of meiosis.
Telophase
The last stage of mitosis, and of meiosis I and II, when, having reached the poles, chromosomes become decondensed, and a nuclear envelope forms around each group.
Tetrad
Chromosome complex formed by the synapsis of homologous chromosomes during meiotic prophase I. A tetrad contains four chromatids.
Zygote
The 2n cell which results from the union of n gametes in sexual reproduction. Species that are not polyploid have haploid gametes and diploid zygotes.
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