Cell Reproduction Chromosomes Mitosis Meiosis Chromosomes Mitosis Meiosis.
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Transcript of #1 castro mitosis meiosis and genetics
Genetics, Mitosis and Meiosis
Biology 1- EOC Review
Genetics- Mendel’s Laws
- Law of Segregation- Two alleles will segregate from each
other so that each gamete carries only a single copy of each allele.
- Law of Independent Assortment - Genes of different traits can segregate
independently during gamete formation.
Dominant vs. Recessive
Dominant Trait is shown/seen Must have a CAPITAL letter to be
dominant Recessive
Trait is masked or not seen if dominant allele is present
Must have a lowercase letter
Incomplete Dominance
The heterozygous phenotype is a blend between the two homozygous phenotypes.
CRCR= Red flowers CRCW= Pink flowers CWCW= White
flowers
Codominance
Both alleles are expressed in the phenotype
Multiple Alleles and Polygenic Traits
Multiple Alleles Genes that have more than two alleles More than two possible alleles exists in a
population. Ex- coat color in rabbits (full color, chinchillas, Himalayan, and albino.
Polygenic Traits Traits that are produced by the interaction
of several genes. Show a wide range of traits. Ex- human skin
colors.
Cell Division
Somatic cells- a body cell that is not passed on to future generations.
Sex or germ cells- a cell that is destined to become a gamete (egg or sperm).
Diploid (2N) – a cell with 2 chromosome sets in each cell; somatic cells.
Haploid (N) – a cell with 1 chromosome set in each cell; germ cells.
Cell Cycle- Interphase
The cell cycle has two major stages; interphase and mitotic phase (M).
The longest phase of the cell cycle is interphase.
Consists of 3 stages; G1, S, and G2.
Interphase
G1 Stage where cells spend the most time. G- growth phase to prepare for S phase.
S S- synthesis Stage of DNA replication
G2 G- growth period. Prepares cell for mitosis.
Mitosis
Cells that undergo mitosis produce genetically identical cells (2N).
Four stages of mitosis Prophase Metaphase Anaphase Telophase/Cytokinesis
Prophase
Beginning of cellular division
Chromosomes condense
Centrioles migrate to poles
Nuclear envelope disappers.
Metaphase
Chromosomes line up along the equator
Centrioles are on opposite poles of the cell
Spindle fibers attach to the centromeres
Anaphase
The centromeres divide
Go from two sister chromatids to 2 separate chromosomes
Spindle fibers pull the chromosomes to opposite poles
Telophase/Cytokinesis
Telophase Chromosomes are at
poles Nuclear envelope
reforms Cytokinesis
Division of cytoplasm Cleavage furrow forms
to separate daughter cells
Cell plate forms in plant cells (eventually forms cell wall)
Meiosis
Meiosis occurs in sexual reproduction A diploid germ cell produces four haploid
daughter cells that become gametes. Have two major stages Meiosis I and
Meiosis II.
Meiosis I- Prophase I
Chromatids pair and crossing over occurs.
Chromosomes condense
Spindle fibers form Nuclear envelope
disappears
Meiosis I- Metaphase I
Chromatid pairs line up along the equator
Spindle fibers attach
Meiosis I- Anaphase I
Spindle fibers pull chromosomes to opposite poles
Sister chromatids remain attached
Meiosis I- Telophase I
Nuclear envelopes reassemble
Spindle fibers disappear
Cytokinesis divides cell.
Meiosis II- Prophase II
Nuclear envelopes disappears
Spindle fibers form
Meiosis II- Metaphase II
Chromosomes line up along the equator
Meiosis II- Anaphase II
Sister chromatids are separated
Spindle fibers pull the separate chromosomes to opposite poles
Meiosis II- Telophase II
Nuclear envelope forms
Spindle fibers disappear
Chromosomes unravel
Cytokinesis divides the cells
Have four haploid daughter cells
Mitosis vs. Meiosis
Mitosis Meiosis2 identical
daughter cells4 genetically
different daughter cells
Diploid (2N) diploid (2N)
Diploid (2N) haploid (N)
Asexual reproduction-
organisms reproduce by
mitosis
Sexual reproduction-
organism produce gametes
Review Questions
Mitosis and meiosis are processes involved in cellular reproduction. Which of the following describes an event that results from mitosis but NOT meiosis? a. Two stages of cell divisionb. Replication of cellular genetic materialc. Daughter cells that are identical to the
parent celld. Four daughter cells that are produced
from each parent cell
Review Questions
Mitosis and meiosis are processes involved in cellular reproduction. Which of the following describes an event that results from mitosis but NOT meiosis? a. Two stages of cell divisionb. Replication of cellular genetic materialc. Daughter cells that are identical to the
parent celld. Four daughter cells that are produced
from each parent cell
Review Questions
Which of the following best compares the processes of mitosis and meiosis? a. Mitosis involves one division cycle and results in diploid
daughter cells, while meiosis consists of two division cycles and results in haploid gametes
b. Mitosis involves one division cycle and results in haploid gametes, while meiosis consists of two division cycles and results in diploid daughter cells
c. Mitosis involves two division cycles and results in diploid daughter cells, while meiosis consists of one division cycle and results in haploid gametes.
d. Mitosis involves two division cycles and results in haploid gametes, while meiosis consists of one division cycle and results in diploid daughter cells.
Review Questions
Which of the following best compares the processes of mitosis and meiosis? a. Mitosis involves one division cycle and results in diploid
daughter cells, while meiosis consists of two division cycles and results in haploid gametes
b. Mitosis involves one division cycle and results in haploid gametes, while meiosis consists of two division cycles and results in diploid daughter cells
c. Mitosis involves two division cycles and results in diploid daughter cells, while meiosis consists of one division cycle and results in haploid gametes.
d. Mitosis involves two division cycles and results in haploid gametes, while meiosis consists of one division cycle and results in diploid daughter cells.
Review Questions
Which of the following best describes how the process of crossing over during meiosis leads to an increase in genetic diversity? a. During prophase I, DNA replication takes place, and
homologous chromosomes trade places with each other before lining up in preparation for metaphase
b. During prophase I, DNA segments are exchanged between homologous chromosomes, resulting in different combinations of alleles
c. During prophase II, fragments of DNA break off of chromosomes and attach to the ends of other chromosomes, resulting in different gene sequences
d. During prophase II, sister chromatids separate from each other, as they travel to opposite ends of the cell, DNA segments of nearby chromosomes are exchanged
Review Questions
Which of the following best describes how the process of crossing over during meiosis leads to an increase in genetic diversity? a. During prophase I, DNA replication takes place, and
homologous chromosomes trade places with each other before lining up in preparation for metaphase
b. During prophase I, DNA segments are exchanged between homologous chromosomes, resulting in different combinations of alleles
c. During prophase II, fragments of DNA break off of chromosomes and attach to the ends of other chromosomes, resulting in different gene sequences
d. During prophase II, sister chromatids separate from each other, as they travel to opposite ends of the cell, DNA segments of nearby chromosomes are exchanged
Review Questions
The allele for brown eyes is dominant to the allele for blue eyes. Which of the following best explains how two brown-eyed parents could produce a blue-eyed child? a. Each parent must be carrying the recessive
allele for blue eyesb. Eye color is a sex-linked trait and male children
could have only the allele for blue eyesc. Mutations after fertilization could alter gene
sequences and change allelesd. One parent must have had only blue eyed
parents
Review Questions
The allele for brown eyes is dominant to the allele for blue eyes. Which of the following best explains how two brown-eyed parents could produce a blue-eyed child? a. Each parent must be carrying the recessive
allele for blue eyesb. Eye color is a sex-linked trait and male children
could have only the allele for blue eyesc. Mutations after fertilization could alter gene
sequences and change allelesd. One parent must have had only blue eyed
parents
Review Questions
When an organism has more than 10 fingers or toes, the condition is known as polydactylism. Although polydactylism is rare, it is a dominant trait. If two cats that are heterozygous for polydactylism mate and have a litter with a total of 12 kittens, how many of them would you expect more than 10 fingers or toes? a. 0b. 6c. 9d. 12
Review Questions
When an organism has more than 10 fingers or toes, the condition is known as polydactylism. Although polydactylism is rare, it is a dominant trait. If two cats that are heterozygous for polydactylism mate and have a litter with a total of 12 kittens, how many of them would you expect more than 10 fingers or toes? a. 0b. 6c. 9d. 12
Review Questions
In pea plants, the allele for white flowers is recessive to the allele for purple flowers. In a generation of pea plants, 89 plants produced purple flowers and 31 plants produced white flowers. Which of the following is the best conclusion you can make about the parent plants of this generation? a. Both parent plants are heterozygous for flower colorb. Both parent plants were homozygous with purple flowersc. One parent plant had white flowers and the other was
heterozygous for flower colord. One parent plant was heterozygous for flower color, and
the other was homozygous with purple flowers
Review Questions
In pea plants, the allele for white flowers is recessive to the allele for purple flowers. In a generation of pea plants, 89 plants produced purple flowers and 31 plants produced white flowers. Which of the following is the best conclusion you can make about the parent plants of this generation? a. Both parent plants are heterozygous for flower colorb. Both parent plants were homozygous with purple flowersc. One parent plant had white flowers and the other was
heterozygous for flower colord. One parent plant was heterozygous for flower color, and
the other was homozygous with purple flowers
Review Questions
Meiosis allows a plant to produce offspring plants with which characteristic? a. A high rate of random mutationsb. Unique combinations of genetic materialc. Traits identical to those of the parent
plantd. Characteristics adaptive to the plants
environment
Review Questions
Meiosis allows a plant to produce offspring plants with which characteristic? a. A high rate of random mutationsb. Unique combinations of genetic materialc. Traits identical to those of the parent
plantd. Characteristics adaptive to the plants
environment
Review Questions
Suppose you cross two heterozygous tall pea plants, both with genotype Tt. What is the probability that the offspring will display the dominant trait?a. 100%b. 75%c. 50%d. 25%
Review Questions
Suppose you cross two heterozygous tall pea plants, both with genotype Tt. What is the probability that the offspring will display the dominant trait?a. 100%b. 75%c. 50%d. 25%
Review Questions
In biology, several different processes make up the cycles for cell division. In which complete process are four new cells created from one original cell? a. Anaphaseb. Meiosisc. Mitosisd. telophase
Review Questions
In biology, several different processes make up the cycles for cell division. In which complete process are four new cells created from one original cell? a. Anaphaseb. Meiosisc. Mitosisd. telophase
Review Questions
The process by which cells replicate is very different than the process by which gametes are produced. Which of the following do both processes have in common? a. Cytokinesisb. Haploid cells formc. Crossing-over occursd. Homologous chromosomes pair up
Review Questions
The process by which cells replicate is very different than the process by which gametes are produced. Which of the following do both processes have in common? a. Cytokinesisb. Haploid cells formc. Crossing-over occursd. Homologous chromosomes pair up