BIO 111 - Exam 2 UPDATED ACTUAL Questions And Correct Answers
Terms in this set (130)
Cytokinesis in animal cells use contractile ring composed of actin microfilaments and myosin motor proteins
to contract rapidly to pinch cell into two, forming the cleavage furrow
What is the contractile ring made of? Actin microfilaments
Myosin motor proteins
What is the indentation on the cell during cytokinesis in Cleavage furrow
animal cells called?
Cytokinesis in plant cells Vesicles accumulate in the middle of the cell
Vesicles bring necessary material to form a temporary structure called a cell plate
Cell plate goes through series of biochemical changes and becomes the cell wall
Homologous chromosomes Contain the same set of genes, but the genes have slightly different DNA
sequences
Before and after DNA replication in homologous pairs Before = one chromatid chromosomes
After = two chromatid chromosomes
Ploidy Describes how many homologs of each chromosome an organism has per cell
Diploid Two homologs of each chromosome per cell
One from each parent
2 of every gene
- same or slightly different from each other
2n
Polyploid More than two homologs of each chromosome
Why go through meiosis? Reproduction
Need one from mom and dad
Mitosis vs. Meiosis Mitosis
- each daughter cell has same # of chromosomes as the original cell, same ploidy
Meiosis
- each daughter cell has 1/2 the # of chromosomes as the original cell, haploid
- reduces the # of chromosomes/cell, ploidy changes
Gametogenesis Making sperm and egg cells
Spermogenesis creates 4 viable haploid sperm cells
, Oogenesis creates 1 mature egg cell and 3 polar bodies, both haploid
Cells and chromosomes at: 1 diploid cell, 2 chromatid chromosomes
Before Meiosis 1 2 haploid cells, 2 chromatid chromosomes
Interkinesis 4 haploid cells, 1 chromatid chromosomes
After Meiosis 2
Prophase 1 Chromosomes condense
Nuclear membrane breaks down
Spindle poles migrate to opposite ends
Spindle network begins to form
Homologous chromosomes pair up and form complexes called bivalents or
tetrads
What are bivalents held together by? Synaptonemal complex proteins
Crossing over In bivalents, genetic material is exchanged between paired chromosomes
Increases genetic variation
Can occur multiple times along chromosomes
Must occur at least once in bivalents
Only occurs in prophase 1 when homologs are paired
Metaphase 1 Homologous pairs line up at metaphase plate
Alignment of homologs on either side is random
Independent assortment
Independent assortment Ensures each new cell contains a mix of homologs from the mom and dad for
greater genetic variation
Anaphase 1 Homologs are separated and segregated to opposite ends by kinetochore
microtubules
Telophase 1 Chromosomes begin to decondense
Spindle network breaks down
Nuclear membranes form
Cytokinesis divides the cell
Terms in this set (130)
Cytokinesis in animal cells use contractile ring composed of actin microfilaments and myosin motor proteins
to contract rapidly to pinch cell into two, forming the cleavage furrow
What is the contractile ring made of? Actin microfilaments
Myosin motor proteins
What is the indentation on the cell during cytokinesis in Cleavage furrow
animal cells called?
Cytokinesis in plant cells Vesicles accumulate in the middle of the cell
Vesicles bring necessary material to form a temporary structure called a cell plate
Cell plate goes through series of biochemical changes and becomes the cell wall
Homologous chromosomes Contain the same set of genes, but the genes have slightly different DNA
sequences
Before and after DNA replication in homologous pairs Before = one chromatid chromosomes
After = two chromatid chromosomes
Ploidy Describes how many homologs of each chromosome an organism has per cell
Diploid Two homologs of each chromosome per cell
One from each parent
2 of every gene
- same or slightly different from each other
2n
Polyploid More than two homologs of each chromosome
Why go through meiosis? Reproduction
Need one from mom and dad
Mitosis vs. Meiosis Mitosis
- each daughter cell has same # of chromosomes as the original cell, same ploidy
Meiosis
- each daughter cell has 1/2 the # of chromosomes as the original cell, haploid
- reduces the # of chromosomes/cell, ploidy changes
Gametogenesis Making sperm and egg cells
Spermogenesis creates 4 viable haploid sperm cells
, Oogenesis creates 1 mature egg cell and 3 polar bodies, both haploid
Cells and chromosomes at: 1 diploid cell, 2 chromatid chromosomes
Before Meiosis 1 2 haploid cells, 2 chromatid chromosomes
Interkinesis 4 haploid cells, 1 chromatid chromosomes
After Meiosis 2
Prophase 1 Chromosomes condense
Nuclear membrane breaks down
Spindle poles migrate to opposite ends
Spindle network begins to form
Homologous chromosomes pair up and form complexes called bivalents or
tetrads
What are bivalents held together by? Synaptonemal complex proteins
Crossing over In bivalents, genetic material is exchanged between paired chromosomes
Increases genetic variation
Can occur multiple times along chromosomes
Must occur at least once in bivalents
Only occurs in prophase 1 when homologs are paired
Metaphase 1 Homologous pairs line up at metaphase plate
Alignment of homologs on either side is random
Independent assortment
Independent assortment Ensures each new cell contains a mix of homologs from the mom and dad for
greater genetic variation
Anaphase 1 Homologs are separated and segregated to opposite ends by kinetochore
microtubules
Telophase 1 Chromosomes begin to decondense
Spindle network breaks down
Nuclear membranes form
Cytokinesis divides the cell
