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Biology > Meiosis and Nondisjunction Disorders > Flashcards

Meiosis and Nondisjunction Disorders Flashcards

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1
Q

What is diploid?

A

Two complete sets of chromosomes, one from each parent.

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2
Q

What is a haploid?

A

One of each chromosome.

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3
Q

What is a gamete?

A

Sperm or egg cell, gametes are haploid.

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4
Q

What is fertilization?

A

The process of one male (sperm) gamete and one female (egg) gamete coming together.

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5
Q

What is a zygote?

A

A cell formed when two gametes come together.

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6
Q

How many divisions and DNA are in meiosis?

A

Two divisions, 1/2 DNA in each of the four cells, are four the cells are genetically different.

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7
Q

What is a somatic cell?

A

Any other cell other than reproductive cells.

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8
Q

What happens during prophase I?

A
  1. Mitosis begins. Chromatin is condensed into chromosomes.
  2. Centrioles form spindle fibers and begin to move to opposite ends of the cell.
  3. Nuclear membrane breaks down and disappears.
  4. Crossing over occurs.
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9
Q

What is crossing over?

A

Homologous Chromosomes exchange genetic information to create genetic diversity in gametes.

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10
Q

What are homologous chromosomes?

A

Homologous chromosomes are chromosome pairs (same number and length).

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11
Q

What happens during metaphase I?

A
  1. Homologous Chromosomes attach themselves to spindle fibers.
  2. Homologous Chromosomes align randomly at the equator as pairs.
  3. Results in new genetic combinations/variations in gametes and therefore, offspring; greater genetic diversity.
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12
Q

What happens during anaphase I?

A
  1. Homologous Chromosomes move apart to opposite poles once attached to spindle fibers (in metaphase).
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13
Q

What happens as an end result of telophase I?

A
  1. The end result after cytokinesis is two cells with sister chromatids remaining to be separated.
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14
Q

Does DNA replicate again before meiosis II?

A

No, DNA doesn’t replicate itself a second time.

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15
Q

What happens during prophase II?

A
  1. Chromatin is recondensed into chromosomes.
  2. Centrioles form spindle fibers and begin to move to opposite ends of the cell.
  3. Nuclear membrane breaks down and disappears.
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16
Q

What happens during metaphase II?

A
  1. Chromosomes attach to the spindle fibers.

2. Sister chromatids randomly line up along the metaphase plate like regular mitosis.

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17
Q

What happens during anaphase II?

A
  1. During Anaphase II, centromeres break and each sister chromatid is pulled to opposite sides of the cell.
18
Q

What happens during Telophase II?

A
  1. The two cells split off, end result is 4 gamete cells that are genetically different from each other.
19
Q

What are inherited mutations?

A

Inherited mutations are when mutations are passed from a parent onto an offspring. All of the offspring’s cells will carry the mutation.

20
Q

What are new mutations in the germline?

A

New Mutations in Germline are when a mutation associated with a disease occurs during gamete production. The offspring can inherit the mutation from an unaffected parent.

21
Q

What are somatic cell mutations in development?

A

The development of specific tissues and organs in the body can be affected by somatic cell mutations that occur early in life. Are inherited by a parent.

22
Q

What are somatic cell mutations later in life?

A

Cancer can result from somatic cell mutations that occur later in life. Are inherited by a parent.

23
Q

What are proto-oncogenes?

A

Proto-oncogenes normally function to accelerate cell growth/division.

24
Q

What happens when proto-oncogenes are mutated?

A

If they’re mutated, they become oncogenes and accelerate cell division and growth way too quickly out of control.

25
Q

What are tumor suppressor genes?

A

Tumor suppressor genes act to slow down cell division, repair DNA mistakes, and tell cells when to die.

26
Q

What happens when tumor suppressor genes are mutated?

A

When mutated, they can cause cells to grow out of control which can lead to cancer.

27
Q

What are DNA repair genes?

A

Normally functions to fix minor damages to DNA when the replication isn’t perfect.

28
Q

What happens when DNA repair genes are mutated?

A

When tumor suppressor genes are mutated, this can lead to cancer because the replication damages aren’t fixed.

29
Q

How do proto-oncogenes relate to a gas pedal?

A

Proto-oncogenes are similar to a gas pedal, helping cells grow and divide at a faster rate. When this gas pedal breaks, this causes the cells to divide uncontrollably.

30
Q

How do tumor suppressor genes relate to a brake pedal?

A

Tumor Suppressor Genes are similar to a brake pedal. Keeps cells from dividing too quickly, just as a brake keeps a car from going too fast.

31
Q

What is nondisjunction?

A

Failure of chromosomes to separate during anaphase in meiosis. This results in gametes having too many/few chromosomes.

32
Q

When does nondisjunction occur?

A

Failure to separate can happen in homologous chromosomes during anaphase I or sister chromatids during anaphase II.

33
Q

What happens when gametes that have nondisjunction are used during reproduction?

A

If these gametes are used during fertilization, this can lead to genetic disorders when the child develops and is born.

34
Q

What is monosomy?

A

This refers to when a homologous chromosome lacks its partner in the genome. Presence of a single chromosome in the homologous pair. Represented as 2n-1 and Turner’s syndrome is an example.

35
Q

What is trisomy?

A

When there is an additional copy of a chromosome present in the genome. Represented as 2n+`1 and Down Syndrome is an example.

36
Q

What is down syndrome?

A

Down syndrome is when a patient has an extra 21st chromosome. Many facial characteristics, and can have cognitive disabilities.

37
Q

What is Edward’s syndrome?

A

Edwards’s syndrome is when a patient has an extra 18th chromosome. Some characteristics are malformed ears and organs, cognitive disabilities, and there is a low survival rate after 6 months.

38
Q

What is Klinefelter’s syndrome?

A

Klinefelter’s syndrome is when a patient has one or more extra X/Y chromosomes; male. Some characteristics are small testes, female-like breasts, female-like voice, and developmental disabilities.

39
Q

What is Patau’s syndrome?

A

Patau’s syndrome is when there is an extra 13th chromosome. Some characteristics are deafness, cleft lip/palate, cognitive disabilities. A low survival rate after 3 months.

40
Q

What is Turner’s syndrome?

A

Turner’s syndrome is when one of the sex chromosomes is missing. Is still female, some characteristics are swelling, broad chest, congenital heart disease, low hairline.

41
Q

What is extra Y chromosome?

A

Extra Y chromosome is when there is an extra Y chromosome. Some characteristics are aggressiveness in behavior may have cognitive disabilities.

Biology (12 decks)

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