Chapter 9 Biology Lab

Somatic cells in humans

Nonreproductive cells

Diploid

2 of each chromosomes (2n)

How many chromosomes are typically in humans (somatic)?

46

With the somatic cells in humans, when are they typically formed?

Mitosis

Gametes in humans

Reproductive cells

Gametes

Sperm and eggs

Haploid

1 of each chromosome (n)

How many chromosomes are in gametes in humans?

Usually 23 chromosomes (22 + 1 sex chromosomes)

With gametes in humans, when are they typically formed?

Meiosis

Haploid cell example

Diploid cell example

Zygote formation

2 haploid gametes fuse to become a diploid cell

Interphase

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis

Interphase

The nucleolus and nuclear envelope are distinct and the chromosomes are in the form of threadlike chromatin

Prophase

The chromosomes appear condensed and the nuclear envelope is not apparent

Metaphase

Thick, coiled chromosomes, each with two chromatids, are lined up on the metaphase plate

Anaphase

The chromatids of each chromosome have separated and are moving toward the poles

Telophase

The chromosomes are at the poles, and are becoming more diffuse. The nuclear envelope is reforming. The cytoplasm may be dividing.

Cytokinesis

Division into two daughter cells

Step 1 of mitosis

Interphase

Step 2 of mitosis

Prophase

Step 3 of mitosis

Metaphase

Step 4 of mitosis

Anaphase

Step 5 of mitosis

Telophase

Step 6 of mitosis

Cytokinesis

Genome

Complete set of genetic information

Chromatin

A complex of DNA and protein that will condense during the cell division of eukaryotes

Chromosomes

DNA molecules packaged within cell

Chromatid

Identical chromosomes paired together that will separate during cell division

What structure is this?

Chromosome

What is the pink structure?

Centromere

What are the top lines pointing at?

Sister chromatids

What structure is this?

Chromatin

What is the purple line?

DNA

When sister chromatids separate, what do they become?

Chromosomes

When attached to each other, one half of the duplicated chromosome is a

Chromatid

What holds sister chromatids together?

Centromere

What is the structure in the box?

Chromatid

Genome

All the genes carried by a set of chromosomes

What does mitosis and cytokinesis begin as?

Diploid

What does mitosis and cytokinesis end as?

Diploid

In mitosis and cytokinesis, what happens to the nucleus and cytoplasm?

They divide

What do the chromatids become during mitosis and cytokinesis?

46 to 92 chromatids to 46

S phase

DNA synthesis

G2 phase

Cell growth

G1 phase

Cell growth

The four phases of the cell cycle

Prophase, metaphase, anaphase, and telophase

Interphase cell cycle steps

G1, S, G2, mitosis, and cytokinesis

Meristem

Active growing region in a plant

Meiosis

A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell,

Alleles

Alternate forms of genes

Meiosis I

Separating homologous chromsomes

Meiosis II

Separating sister chromatids

Number of chromatids in the beginning of interphase

46

Number of chromatids at the end of interphase

92

Chromosomes are replicated to from

Sister chromatids

Prophase I

Homologous chromosome pairs together at the synaptonemal complex

What is formed during synapsis?

Tetrad

What is the first line?

Homologous chromosomes

What is the second line?

Centromere

What is the third line?

Kinetochore

What is the forth line?

Synaptonemal complex

What is the fifth line?

Sister chromatids

What does prophase one result in?

Genetic recombination

Metaphase I

Homologous chromosomes arranged at equatorial plane

Independent assortment

Genetic diversity

Metaphase I

Anaphase I

Anaphase I

Homologous chromosomes separate and are distributed to different nuclei

How many chromatids are in chromosomes with Anaphase I

2

Telophase I and Cytokinesis

What is produced following Telophase I and Cytokinesis?

Two haploid daughter cells

Although two haploid daughter cells are produced, how many chromosome sets are present during Telophase I and Cytokinesis?

One

Meiosis I starts as a

Diploid

Meiosis I ends as a

Haploid (still have sister chromatids)

Step one of Meiosis I

Prophase I

Step two of meiosis I

Metaphase I

Step

Step three of meiosis I

Anaphase I

Step four of meiosis I

Telophase I and cytokinesis

Is there DNA replication at the beginning of meiosis II?

No

What does meiosis II start with?

2 haploid parent cell (with sister chromatids)

What does meiosis II end with?

4 haploid daughter cells

Starting cell in meiosis II

2n = 4

What does the 2n mean in 2n=4?

Diploid

What does 4 mean in 2n=4?

4 chromosomes

During anaphase II, what occurs?

Sister chromatids separate and one is distributed to each daughter cell, making a chromosome

What occurs during telophase II and cytokinesis?

Results in 4 haploid daughter cells with unduplicated chromosomes

Mendel’s 1st law

Segregation of alleles during meiosis

Diploid organism

Pair of chromosomes (2 copies of each gene; one from each parent)

Locus

Particular gene

2 alleles at locus are often written as?

Aa or Bb

Dominant gene

Capital letter

Recessive gene

Lowercase letter

Homozygous

AA or aa (same)