Biology Chapter 13

Front 1

Genetics

Back 1

the scientific study of the transmission of traits from parents to offspring (heredity) and the varitions between and within generations

The scientific study of heredity and hereditary variation

Front 2

Living Organisms

Back 2

Are distinguished by their ability to reproduce

Front 3

Heredity

Back 3

The transmission of traits from one generation to the next

Front 4

Variation

Back 4

Shows that offspring differ somewhat in appearance from parents nad siblings

Front 5

Asexual Reproduction

Back 5

Mitosis produces genetically identical cells

May result in clones of one parent

Front 6

Sexual Reproduction

Back 6

Two parents give rise to offspring that have unique combinations of genes inherited from parents

Front 7

Meiosis

Back 7

a special type of cell division that halves the chromosome number and provides a haploid set of chromosomes to each gamete

Front 8

Haploid Cell

Back 8

contains only one set of chromosomes

Generally in humans 23 chromosomes (n=23)

Haploid cells produce Diploid cells with fertilization (fusing two gametes)

Front 9

Diploid Cell

Back 9

has 2 sets of each of its chromosomes

One set of chromosomes from mother and one set from the father

Generally humans, 26 chromosomes (2n=46)

Diploid produce Haploid daughter cells with Meiosis (halving the chromosome number)

Front 10

Types of haploid and diploid cells in animals

Back 10

Gamete (germ cells) (sperm and egg cells) are haploid cells

Somatic cells (body cells) are diploid cells

many exceptions

Front 11

Sexual Maturity

Back 11

the ovaries and testes produce haploid gametes by meiosis

During fertilization these gametes, sperm and ovaum, fuse, forming a diploid zygote

Front 12

The Zygote

Back 12

Develops into an adult organism by mitosis

Front 13

Chromosomes in Human Cells

Back 13

A Kayotype is an ordered, visual representation of the chromosomes in a cell

Front 14

Homologous Chromosomes

Back 14

occur in pairs

have the same characteristics: length, centromere position, gene Loci

Both homologous chromosomes carry genes controlling the same inherited characters but usually pairs are not identical

Front 15

Sex Chromosomes

Back 15

Determines the sex of the individual

In Humans
are represented by X and Y

XX being female

XY being male

are non-homologous

Front 16

Autosome chromosomes

Back 16

Do not dtermine sex (body genes)

Front 17

Behavior of Chromosomes in Life Cycle

Back 17

In cell in which DNA synthesis has occurred all the chromosomes are duplicated and thus each consists of two identical sister chromatids

Front 18

Meiosis

Back 18

reduces the number of chromosome sets from diploid to haploid

Front 19

Meiosis I

Back 19

Reduces the number of chromosomes from diploid to haploid

tetrads line up on the metaphase plate

homologous pairs separate in anaphase I with one homologue moving toward each pole

Cytokenesis usually occurs during telophase I

There is no replication of genetic material prior to the 2nd division of meiosis

Front 20

Meiosis II

Back 20

Produces 4 haploid daughters

Looks like a regular mitotic division in which chromosomes line up individually on the metaphase plate and sister chromatids separate and move apart in anaphase II. At the end of telophase II there are four haploid daughter cells.

Front 21

Interphase I

Back 21

Interphase I (each chromosome replicates, producing 2 genetically identical sister chromatids that remain attached to their centromeres. During prophase I homologous chromosomes synapse and crossovers may occur forming chiasmata

Front 22

Stages of Meiosis

Back 22

Stage 1 - Interphase I

Stage 2 - Metaphase I

Stage 3 - Anaphase I

Stage 4 - Telophase I

Stage 5 - Cytokenesis

Meiosis II

Stage 1 - Anaphase II

Stage 2 - Telophase II

Front 23

Differences between Mitosis and Meiosis

Back 23

2 division in Meiosis

1 division in Mitosis

By events in Meiosis I
Tetrad Information

synapsis with crossing over at chiasmata

Homologous pairs separate

Meiosis makes non-identical daughter cells (haploid cells from diploid cells)

Mitosis makes identical daughter cells

Front 24

Prophase I of Meiosis

Back 24

Tetrads form

Tetrads are paired, homologoug, duplicated chromosomes

Synapsis and crossing over occur in tetrads. Homologous chromosomes physically connect and exchange genetic information

Front 25

Separation of chromosomes

Back 25

Anaphase I of meiosis, tetrads separte into homologous pairs that move toward opposite poles of the cell

In anaphase II of meiosis, the sister chromatids separate

Front 26

Meiosis I

Back 26

called reductional division because it reduces the chromosome sets from two (diploid) to one (haploid). The sister chromatids of each homologue do not separate until meiosis II

Front 27

Sex Chromosomes

Back 27

Determines the sex of the individual

In Humans
are represented by X and Y

XX being female

XY being male

are non-homologous

Front 28

Autosome chromosomes

Back 28

Do not dtermine sex (body genes)

Front 29

Behavior of Chromosomes in Life Cycle

Back 29

In cell in which DNA synthesis has occurred all the chromosomes are duplicated and thus each consists of two identical sister chromatids

Front 30

Meiosis

Back 30

reduces the number of chromosome sets from diploid to haploid

Front 31

Meiosis I

Back 31

Reduces the number of chromosomes from diploid to haploid

tetrads line up on the metaphase plate

homologous pairs separate in anaphase I with one homologue moving toward each pole

Cytokenesis usually occurs during telophase I

There is no replication of genetic material prior to the 2nd division of meiosis

Front 32

Meiosis II

Back 32

Produces 4 haploid daughters

Looks like a regular mitotic division in which chromosomes line up individually on the metaphase plate and sister chromatids separate and move apart in anaphase II. At the end of telophase II there are four haploid daughter cells.

Front 33

Interphase I

Back 33

Interphase I (each chromosome replicates, producing 2 genetically identical sister chromatids that remain attached to their centromeres. During prophase I homologous chromosomes synapse and crossovers may occur forming chiasmata

Front 34

Stages of Meiosis

Back 34

Stage 1 - Interphase I

Stage 2 - Metaphase I

Stage 3 - Anaphase I

Stage 4 - Telophase I

Stage 5 - Cytokenesis

Meiosis II

Stage 1 - Anaphase II

Stage 2 - Telophase II

Front 35

Differences between Mitosis and Meiosis

Back 35

2 division in Meiosis

1 division in Mitosis

By events in Meiosis I
Tetrad Information

synapsis with crossing over at chiasmata

Homologous pairs separate

Meiosis makes non-identical daughter cells (haploid cells from diploid cells)

Mitosis makes identical daughter cells

Front 36

Prophase I of Meiosis

Back 36

Tetrads form

Tetrads are paired, homologoug, duplicated chromosomes

Synapsis and crossing over occur in tetrads. Homologous chromosomes physically connect and exchange genetic information

Front 37

Separation of chromosomes

Back 37

Anaphase I of meiosis, tetrads separte into homologous pairs that move toward opposite poles of the cell

In anaphase II of meiosis, the sister chromatids separate

Front 38

Meiosis I

Back 38

called reductional division because it reduces the chromosome sets from two (diploid) to one (haploid). The sister chromatids of each homologue do not separate until meiosis II

Front 39

Sex Chromosomes

Back 39

Determines the sex of the individual

In Humans
are represented by X and Y

XX being female

XY being male

are non-homologous

Front 40

Autosome chromosomes

Back 40

Do not dtermine sex (body genes)

Front 41

Behavior of Chromosomes in Life Cycle

Back 41

In cell in which DNA synthesis has occurred all the chromosomes are duplicated and thus each consists of two identical sister chromatids

Front 42

Meiosis

Back 42

reduces the number of chromosome sets from diploid to haploid

Front 43

Meiosis I

Back 43

Reduces the number of chromosomes from diploid to haploid

tetrads line up on the metaphase plate

homologous pairs separate in anaphase I with one homologue moving toward each pole

Cytokenesis usually occurs during telophase I

There is no replication of genetic material prior to the 2nd division of meiosis

Front 44

Meiosis II

Back 44

Produces 4 haploid daughters

Looks like a regular mitotic division in which chromosomes line up individually on the metaphase plate and sister chromatids separate and move apart in anaphase II. At the end of telophase II there are four haploid daughter cells.

Front 45

Interphase I

Back 45

Interphase I (each chromosome replicates, producing 2 genetically identical sister chromatids that remain attached to their centromeres. During prophase I homologous chromosomes synapse and crossovers may occur forming chiasmata

Front 46

Stages of Meiosis

Back 46

Stage 1 - Interphase I

Stage 2 - Metaphase I

Stage 3 - Anaphase I

Stage 4 - Telophase I

Stage 5 - Cytokenesis

Meiosis II

Stage 1 - Anaphase II

Stage 2 - Telophase II

Front 47

Differences between Mitosis and Meiosis

Back 47

2 division in Meiosis

1 division in Mitosis

By events in Meiosis I
Tetrad Information

synapsis with crossing over at chiasmata

Homologous pairs separate

Meiosis makes non-identical daughter cells (haploid cells from diploid cells)

Mitosis makes identical daughter cells

Front 48

Prophase I of Meiosis

Back 48

Tetrads form

Tetrads are paired, homologoug, duplicated chromosomes

Synapsis and crossing over occur in tetrads. Homologous chromosomes physically connect and exchange genetic information

Front 49

Separation of chromosomes

Back 49

Anaphase I of meiosis, tetrads separte into homologous pairs that move toward opposite poles of the cell

In anaphase II of meiosis, the sister chromatids separate

Front 50

Meiosis I

Back 50

called reductional division because it reduces the chromosome sets from two (diploid) to one (haploid). The sister chromatids of each homologue do not separate until meiosis II

Front 51

Comparison of Mitosis and Meiosis

Back 51

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