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genetics chapter 1-2
Question | Answer |
---|---|
What are somatic cells | human cells |
how many chromosomes do somatic cells carry? | 23 pairs, 46 chromosomes |
non-sex chromosomes | autosomes |
What deturmines the cell is a female cell? | XX |
How many autosomes are in a cell? | 1 pair out of the 23 pairs |
What is genetic information composed of? | DNA |
DNA is organised into what? | genes |
What states do cells alternate between? | division and nondivison |
What is the cell cycle? | the sequence of events inbetween mitotic divisions |
What are the three parts of the cell cycle? | interphase, mitosis, and cytokinesis |
What are the phases of interphase and whats the main purpose of interphase? | G1, S, G2, growth because the daughter cell is only half of what the parent cell was |
What happens in the G1 phase? | 1. organelles, membranes, and ribosomes are made.(almost 2x the size) |
What happens during the S phase? | a duplicate copy of each of the chromosomes are made, chromosomes become double stranded |
What happens during the G2 phase? | mitochondria divide, the precursors of spindle fibers are made |
What is the state that cells go into that never divide? | G0 |
What happens in prophase? | chromosomes condense, nuclear envelope disappears, centrioles divide and go to opposite poles of the cell, spindle fibers form and attach to the chromosome |
What are the steps of earlier prophase? | 1. chromosomes condense and become reconizable as chromosomes 2. chromosomes continue to condense until it is two long strands called a chromotid 3. the chromotids are held together by a centromere. These conected chromotids are called sister chromotids. |
What are the steps of later prophase? | 4. the centrioles go to opposite sides 5. the nuclear envelope breaks up. 6. spindles form from the centrioles and attach to the centromeres |
What are the steps of metaphase? | 1. the chromosomes go to the middle of the cell and line up |
what are the steps of anaphase? | 1. the centromeres divide (sister chromotids separate turning into chromosomes) 2. the spindle fibers pull the chromosomes to opposite ends of the cell 3. there are 23 sets of chromosomes on each side of the cell |
what are the steps of telaphase? | there are two clusters of chromosomes on each side of the cell 1. the chromosomes start to uncoil 2. a new nuclear membrane starts to form around each cluster 3. mitosis is done |
what happens in cytokinesis? | 1. a cleavage furrow forms between the two membranes 2. the cleavage furrow gradually tightens by contraction of filaments 2. the cells cytoplasm is divided into two parts and the cell is divided into two |
what is the hayflick limit? | the amount of times a cell can divide. |
diploid number | 2n- for all cells that don't undergo miosis |
haploid number | n- cells that undergo miosis |
gametes | sex cells |
what happens in prophase 1? | 1. the chromosomes condense to threadlike form they attach to their homologue (same type of father chromosome) and they swap information 2. the nuclear membrane disappears 3. the spindle fibers attach to each chromosome |
what happens in metaphase 1? | 1. the pairs of two sister chromotids are lined up midway between the centrioles 3. the spendle is completely formed |
What happens in anaphase 1? | members of each pair separate from each other and moce to opposite sides of the cell |
what happens in telophase1? | cytokinesis 1. the cytoplasm divides at some point 2. there are now two hapliod cells with one of each type of chromosome that was in the parent cell |
what happens inbetween telophase 1 and prophase 2? | the centrioles of the new cell are separated and moved to opposite sides of the spindle pole |
what happens in prophase 2? | microtubules attach to the chromosomes, which are pushed to the middle |
what happens in metaphase 2? | the duplicated chromosomes attach to the spinde fibers at their centromeres |
what happens in anaphase 2? | 1. the attachment to the centromeres detach for the first time, 2. the chromatids are turned into chromosomes and go to opposite sides of the cell |
what is the final result of telaphase 2? | 1. there are four daughter nuclei 2. each daughter cell is haploid 3. cytokinisis divides cytoplasm and all chromosomes are in the unduplicated state |
What is the number of chromosome combinations? | 2 ^n |