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32 Cards in this Set
- Front
- Back
What are the types of reproduction?
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Asexual and sexual
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Asexual Reproduction
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-Production of offspring by a single parent
-Binary fission -preformed by bacteria, protists, and fungi |
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Sexual Reproduction
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-Sperm and egg each carry one set of genetic information
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Who developed the cell theory?
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Schleiden, Schwann, and Virchow
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What is the cell theory?
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-Cells are the basic unit of life
-All living organisms are composed of cells -Cells only come from preexisting cells |
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What does cell reproduction ensure?
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The continuty of life from generation to generation
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What does cell reproduction make possible?
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A ferilized egg to develop through various embryonic stages and into an adult
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How do prokaryotes reproduce?
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Through binary fission
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How does binary fission work?
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-Genes are carried on circular DNA
-Chromosomes are duplicated. -Cells divide into two identical copies |
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How many genes do the chromosomes of prokaryotes carry?
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about 3000
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What are the chromosomes made of?
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60% protein
40% DNA |
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How many genes do the chromosomes of eukaryotes carry?
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about 100000
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What are chromosome composed of?
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Chromatin
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What is chromatin?
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A combination of DNA and histone proteins.
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What happens when chromatin coils up?
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It forms distinct chromosomes
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What happens before cell divison?
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The chromosomes divide into two copies forming sister chromatids
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What type of gene do the sister chromatids contain?
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Identical genes
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What holds the sister chromatids together and where?
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A centromere in the middle
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What is a centromere?
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A protein disk
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What is the G0 phase?
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The phase for cells that do not replicate such as muscle and nerve cells
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What is the G1 phase?
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-Period before DNA synthesis begins
-Time when cell increases its supply of proteins, organelles, and grows in size |
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What is the S phase?
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-Phase when DNA synthesis occurs
-At the beginning each chromosome is single and at the end there are two sister chromatids |
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What is the G2 phase?
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-Spans the time from the completion of DNA synthesis to the onset of cell division
-Time of metabolic activity (proteins are made for cell divison) |
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What is the M phase?
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-mitosis
-nulceus and its content divide and are evenly distributed to form two daughter nuclei -chromosomes are visible |
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What is the C phase?
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-cytokinesis
-usually begins before mitosis is complete -division of cytoplasm |
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What happens during propahse?
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-nucleus disappears
-chromosomes condense -spindle fibers form -centrioles move to poles |
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What do the spindle fibers do?
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Help to move chromosomes
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What do the centrioles do?
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Help form spindle fibers
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Where are centrioles found?
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In animal cells
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What happens during metaphase?
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-chromosomes line up in a single file line in middle of cell
-spindle fibers span length of cell -kinecticore connencts spindle fibers to centromere |
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What happens during anaphase?
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-sister chromatids seperate
-spindle fibers shorten -cell elongates |
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What happens during telophase?
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-opposite pf propahse
-nucleus forms -chromosomes loosen -spindle fibers disappear -centrioles move back to the middle of the cell |