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Human Bio > Chapter 10 > Flashcards

Chapter 10 Flashcards

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Biology 101 flashcards
1
Q

describe the cell cycle

A

G1 phase - cells grows, produces new proteins. S phase - cell makes exact copy of it’s DNA G2 phase - cell grows again M phase - cell divides to 2 daughter cells

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2
Q

Summarize Interphase

A

period between cell divisions, coversG1-G2 phases DNA doubles

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3
Q

Summarize prophase

A

cell nucleus disappears, two centrioles become visible, nucleolus disappears, nuclear membrane breaks down, chromatin threads tightly coil and are now chromosomes

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4
Q

Summarize metaphase

A

Chromosomes meet at the center of the cell, each centromere is attached to spindle fiber coming from centrioles

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5
Q

Summarize Anaphase

A

Chromosomes separate into chromatids, spindle fibers pull them to opposite poles of cell

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6
Q

Summarize telophase

A

Two sets of chromosomes form tight groups, nuclear membrane forms around each group and nucleolus appears, spindle fibers disappear, chromosomes uncoil to form chromatids.

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7
Q

What is cytokinesis

A

Separation of the cytoplasm, a furrow forms and deepens until it splits the cell

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8
Q

What is differentiation

A

Process by which cells become specialized; this occurs under the right conditions

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9
Q

What are stem cells

A

Cells that are not specialized and can divide repeatedly by mitosis

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10
Q

Name and describe the 3 types of stem cells

A

Totipotent stem cells-ability to form embryos and the membranes that surround and nourish it
Pluripotent-capable or giving rise to most tissue in organism
Multipotent-give rise to cells with specific function

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11
Q

What is the haploid number

A

Half the number of chromosomes, 23, daughter cells of meiosis have this number

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12
Q

What are homologous chromosomes

A

pairs of chromosomes that are identical in shape and carry genetic information that influences the same characteristics.

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13
Q

How many chromosomes does a gamete have

A

Haploid, 23

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14
Q

What happens during prophase I (meiosis)

A

chromosomes become visible as
long threads, each has already undergone DNA replication, consists of a pair of chromatids, homologous pairs form, DNA tightly coils. Meanwhile, spindles are forming at poles of cell

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15
Q

Describe metaphase I (meiosis)

A

homologous chromosomes are arranged at middle of cell and attach to spindle fibers

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16
Q

Describe anaphase I

A

homologous chromosomes separate (one member of each pair consisting of two chromatids), 23 chromosomes move to each pole

17
Q

Describe telophase I

A

chromosomes decondense and nuclear membrane reforms. Cytokinesis then occurs with cytoplasm splitting and producing two separate cells

18
Q

Describe the second meiotic division

A

New spindles form, chromosomes meet at middle, spindles pull chromatids to poles of cell (now chromosomes), nuclear membranes form and cytoplasm begins to split. Four total daughter cells are made

19
Q

What is the main difference between mitosis and meiosis

A

mitosis produces identical diploid cells for growth and repair within the tissues,
whereas meiosis produces haploid gametes for sexual reproduction.

20
Q

Do homologous chromosomes pair up in meiosis or mitosis?

A

They pair up in meiosis but not mitosis

20
Q

Briefly outline the separation occurrences during first meiotic division and second meiotic division

A

At first meiotic division, members of homologous pairs separate so that new cells get a haploid set of chromosomes. At second division, chromatids separate, giving four haploid cells.

21
Q

What is crossing over (meiosis)

A

Where chromatids may break, cross and exchange segments during homologous pairing (occurs during prophase I). This creates new combinations of genes

22
Q

What is the chiasma

A

The point at which two chromatids cross

23
Q

What is recombination

A

A new combination of alleles along the chromosome resulting from crossing over

24
Q

What is non-disjunction

A

When one or more of the
chromosome pairs fail to separate during
meiosis resulting in one daughter cell with one less chromosome and one with one more chromosome. Can happen during first or second meiotic division

25
Q

What is trisomy

A

When an individual inherits an extra copy of a chromosome, 3 copies instead of 2. Results in down syndrome or trisomy 21. Inherits extra copy of chromosome 21

26
Q

What is monosomy

A

Individual only inherits one chromosome and not two.

27
Q

What is partial trisomy an partial monosomy

A

Partial trisomy: part of an extra chromosome is attached to one of the other chromosomes.
Partial monosomy: part of a chromosome is missing – part of the chromosome has two copies, but part has only one copy.

28
Q

What is independent assortment

A

The random combination of alleles due to allele pairs separating independently of one another

29
Q

When may crossing over occur?

A

Prophase I

30
Q

Explain how non-disjunction results in Down syndrome .

A

Non-disjunction is when one or more pair of chromosomes or sister chromatids fail to separate during anaphase. This results in one daughter cell having an extra chromosome and the other having one less. If this occurs for chromosome 21, it is called down syndrome. The cell has 2 copies of chromosome 21. When the cell is fertilized, it will have 3 copies.

31
Q

What is cancer and a tumor

A

Cancer is uncontrollable cell growth. A tumor is the abnormal mass that grows from cancer

32
Q

What is a benign tumor

A

One that does not spread. It grows and presses on surrounding tissues or organs.

32
Q

What does a malignant tumor mean. What is the name of this condition

A

The tumor cells can spread to other parts of the body. They can invade tissue, lymph and blood vessels. This is metastasis

33
Q

Give examples of carcinogens

A

UV-rays, X-rays, ionizing radiation, viruses like HPV, alcohol, cigarettes, asbestos

34
Q

How do daughter cells of mitosis remain identical in genetic information?

A

Homologous pairing does not occur in mitosis making it impossible for crossing over, and the new assortment of alleles. Therefore the make-up of chromosomes remains the same.

Human Bio (6 decks)

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