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27 Cards in this Set
- Front
- Back
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how do cells of prokaryotes and eukaryotes divide
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binary fission (pro)
mitosis (euk) |
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how does prokaryote genome appear
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one chromosome, a single DNA, circular
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what two factors initiate cell division for binary fission
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-nutrient concentration
-environmental conditions |
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steps of binary fission
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1. circular DNA replicates
2. the cell grows (doubles) 3. daughter DNA's segregate 4. cytokinesis |
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how is DNA oriented for eukaryotes
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the DNA is linear
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Which two states does eukaryotic DNA occur
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-uncoiled: chromatin (transcription, protein synthesis)
-coiled: chromosome (cell division) |
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what does a nucleosome consist of
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DNA + 8 histone molecules
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define chromatin
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densely coiled DNA and protein
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what are histones
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proteins found inside chromosomes
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define a gene
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a stretch of DNA that codes for a protein
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what are the stages of the cell cycle
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interphase (G1, S, G2)
mitosis |
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what occurs during G1
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normal cell functions
-DNA must be uncoiled to perform protein synthesis |
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what occurs during S
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DNA is replicated before cell divison
-DNA is still coiled because it must be accessible |
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what occurs during G2
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preparation for mitosis
-DNA begins to coil; chromatin becomes chromosomes |
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what are the four steps of mitosis in order
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prophase
metaphase (prometa) anaphase telophase PMAT |
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what occurs during prophase
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chromatin coils to become more compact, condensing into visible chromosomes
-chromosomes consist of identical, paired sister chromatids |
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what occurs during prometaphase
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nuclear envelope (which holds DNA) breaks down
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what occurs during metaphase
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chromosomes line up individually along the middle
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what occurs during anaphase
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paired sister chromatids separate and migrate to opposite sides of cell
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what occurs during telophase
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nuclear envelope and nucleus reforms, cell enters interphase
-cytokinesis occurs (division of cytoplasm) |
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for what cells does mitosis occur; and what purpose
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-somatics cells (cells of the body)
-cell growth, tissue renewal |
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define karyotype
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number, shapes, and sizes of chromosomes in a cell
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define ploidy
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number of homologous sets of chromosomes in a cell
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define diploid
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one set of chromosomes from each parent; two copies of genome
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define haploid
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one copy of genome (gamete)
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what molecules make up a chromosome
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DNA and proteins
(chromatids make up chromosomes, and chromatids consist of coiled DNA strands and the protein (histones) that lie within the DNA) |
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what do spindles do in mitosis/meiosis
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speed up the process
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