Mitosis Section 4.2

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Questions and Answers

What is the primary role of genes within chromosomes?

To enhance replication of chromosomes

To protect the DNA from mutations

To determine the size and shape of the chromosome

To serve as units of information about heritable traits (correct)

How many alleles do individuals inherit for each gene?

Four, two from each parent

Three, one from each parent and a third from mutations

One from the sperm

Two, one from the egg and one from the sperm (correct)

What characterizes homologous chromosomes?

They have the same size, shape, and genes, but possibly different alleles (correct)

They can be different lengths but share the same genes

They always have identical alleles

They are found only in diploid organisms

What is a nucleosome composed of?

A histone protein with DNA wrapped around it Signup and view all the answers

What determines the expression of a trait in an organism?

The combination of alleles inherited for each gene Signup and view all the answers

What is the primary purpose of mitosis in somatic cells?

To enable growth and repair Signup and view all the answers

Which phase of the cell cycle is the longest?

Interphase Signup and view all the answers

During which mitotic phase do chromosomes align in the middle of the cell?

Metaphase Signup and view all the answers

What happens to the chromosomes during Anaphase?

They are pulled apart to opposite ends of the cell Signup and view all the answers

What is formed during Telophase?

Nuclear membranes around chromosomes Signup and view all the answers

Which structure helps organize spindle fibers during mitosis in animal cells?

Centrosomes Signup and view all the answers

What is the final stage of the cell cycle called?

Cytokinesis Signup and view all the answers

Which term refers to the duplicated copies of a chromosome during mitosis?

Sister chromatids Signup and view all the answers

What is the primary function of chromosomes in a cell?

To organize DNA for fitting inside the nucleus Signup and view all the answers

Which statement correctly describes the difference between prokaryotic and eukaryotic cells?

Prokaryotic cells have messy single-stranded DNA, while eukaryotic cells have double-stranded DNA. Signup and view all the answers

What is the result of a chromosome being duplicated during interphase?

Two identical chromosomes are held together by a centromere. Signup and view all the answers

How many total chromosomes do human cells have?

46 Signup and view all the answers

In which zone does the formation of a cell plate primarily occur?

Meristem zone of plant cells Signup and view all the answers

What are the two forms of DNA found in cells?

Single-stranded and double-stranded Signup and view all the answers

What is the role of histone proteins in relation to DNA?

To package DNA into chromosomes in eukaryotic cells Signup and view all the answers

What is the structure of DNA commonly described as?

A double helix Signup and view all the answers

Study Notes

Mitosis Overview

Mitosis is essential for growth and repair of tissues.
Occurs in all somatic (body) cells resulting in two genetically identical daughter cells.

Cell Cycle

The cell cycle consists of interphase and the mitotic phase.
Interphase includes three stages: G1, S, and G2.

Interphase (G1, S, G2)

Longest stage of the cell cycle focusing on preparation for division.
Cells grow and duplicate organelles.
DNA is replicated, forming "doubled chromosomes" in an X shape.

Stages of Mitosis

Mitosis involves four distinct stages: Prophase, Metaphase, Anaphase, and Telophase.

Prophase

Chromosomes become visible as the nuclear membrane dissolves.
Chromosomes are released into the cytoplasm.

Metaphase

Chromosomes align in the cell's center.
Replicated chromosomes are connected by centromeres; each copy is a chromatid.

Anaphase

Spindle fibers pull chromatids to opposite ends of the cell.
Each new cell receives a complete set of chromosomes.

Telophase

Chromosomes reach opposite ends; new nuclear membranes form around each set of chromosomes.
The cell is not yet divided.

Cytokinesis

Final stage of the cell cycle where remaining contents are divided.
In animal cells, microfilaments form a cleavage furrow; in plant cells, carbohydrate vesicles form a cell plate.
Results in two identical cells.

Prokaryotic vs Eukaryotic Cells

Prokaryotic cells: No nucleus, membrane-bound organelles, divide without mitosis.
Eukaryotic cells: Have a nucleus, organized DNA, divide by mitosis.

DNA and Chromosomes

DNA (deoxyribonucleic acid) is a biological molecule composed of nucleotides.
Double-stranded structure forms a double helix.
Each human cell contains approximately 3 meters of DNA packaged within the nucleus.

Chromosome Structure

Humans have 46 chromosomes (23 pairs); all must be duplicated during interphase.
Chromosomes ensure accurate DNA distribution during mitosis.

Genes and Alleles

Genes are segments of DNA that code for heritable traits.
Each gene can exist in different versions known as alleles.
Alleles inherited from each parent determine expressed traits.

Chromosomal Characteristics

Homologous chromosomes are similar in size, shape, and gene composition, but may carry different alleles.
Each chromosome pair consists of one from the mother (egg) and one from the father (sperm).

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Description

Explore the process of mitosis and its significance in growth and repair within somatic cells. This quiz covers the key stages of mitosis, the cell cycle, and the production of genetically identical daughter cells.