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BIO > MOD D > Flashcards

MOD D Flashcards

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Biology 101 flashcards
1
Q

What do chromosomes look like in a cell

A

-Loose noodle structure
-copied and condensed spools of yarn when cell splits in 2

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2
Q

How many chromosomes in human body cells vs gametes (human sex cells)

A

46, 23

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3
Q

Number of choromosomes in meiosis phases

A

Interphase; 46 chromosomes, 46 chromatids—> 46 chromosomes, 92 chromatids
Meiosis 1; 46chromo, 92chroma—> 2 cells, each with 23chromo, 46 chroma
Meiosis 2; the 2 cells divide into 4 cells, each with 23chromo and 23 chroma

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4
Q

Define meiosis

A

Meiosis is a special type of nuclear division that produces gametes with half the amount of genetic information of the original Cell

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5
Q

Where does meiosis occur in females and males

A

Ovaries and testes

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6
Q

Define chromosome

A

Tightly coiled combination of DNA molecules and his stone proteins found in cell nucleus 

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7
Q

Define genes

A

Specific segments of DNA directing the synthesis of proteins that play a structural or functional role within the cell 

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8
Q

Define somatic cells 

A

Somatic cells are all cells except eggs or sperm and they have 46 chromosomes which are actually 23 pairs of homologous chromospmes

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9
Q

Define diploid

A

Any cell with two of each kind of chromosome

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10
Q

Define sex chromosome

A

One of the 23 pairs of chromosomes (x&y) which determines whether a person is a male or female

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11
Q

Define autosomes

A

22 of 23 pairs of chromosomes, determine the expression of most of a persons inherited characteristics

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12
Q

Define mitosis

A

Phase of the cell cycle, where one nucleus divides into two daughter nuclei with the same number, and kinds of chromosomes

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13
Q

Define cell cycle

A

Two major phases interphase and cell division

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14
Q

Define interphase

A

-longest Period of the cell cycle between cell divisions
-cell carries out its functions and grows
-DNA and organelles are duplicated

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15
Q

What are the three parts of interphase?

A

-g1; time of major cell growth before DNA synthesis
-s;  DNA is synthesized (Replicated)
-g2; Time of growth after synthesis but before mitosis

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16
Q

Define chromatin

A

Long, thin threads that the genetic material is in throughout interphase

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17
Q

Define centromere

A

During the S-phase chromosomes are replicated and the two copies, each a replicate of the original chromosome, see attached to each other at the middle region (centromere)

18
Q

Define chromatid

A

Each copy of chromosome is a chromatid
Too attached chromatids are genetically identical, and are referred to as sister chromatids

19
Q

What is the G0 stage

A

 Specialize cells like nerve cells, lose their ability to divide but continue carrying out their normal cellular activities

20
Q

What are the two conditions for cell division?

A

The cell cycle requires precise, timing and accuracy, which is monitored by proteins to ensure appropriate conditions for cell division, and accurate DNA replication

21
Q

Define cytokinesis

A

-The division of the cytoplasm that occurs towards the end of mitosis in telophase
-microfilaments contract until the cell is pinched into 2 daughter cells

22
Q

What are the four stages of mitosis

A

Prophase metaphase, anaphase telophase

23
Q

Define prophase

A

-Chromatin condenses and forms chromosomes while dna wraps around histones
-compact structure, nuclear membrane begins to break down
-mitotic spindle forms outside the nucleus in cytoplasm
-centrioles move opposite eachother

24
Q

Define metaphase

A

-The chromosomes attached to the mitotic spindles and form an equator
-The equator ensures that when the chromosomes split, each daughter cell receives one chromatid from each of the 46 chromosomes

25
Q

Define anaphase

A

-sister chromatids begin to separate at centromere creating separate entities
-Spindle, fibers, pull chromosomes opposite each other
-chromosome collections are located at two poles of the cell

26
Q

Define telophase

A

-Nuclear envelope forms around each chromosome group
-mitotic spindles gone
-chromosomes threadlike

27
Q

Define Karyotypes

A

-Arrangements of chromosomes in pairs, based on physical characteristics
eg) centromere location, overall length
-Numbered largest to smallest

28
Q

Why are karyotypes used?

A

-Diagnostic purposes
-structure &# of chromo

29
Q

What do somatic cells contain?

A

A homologous pair of each type of chromosome, one from father, and one for mother, making them diploid

30
Q

Define haploid

A

Means they only have one member of each homologous pair of chromosomes eg) gametes (egg or sperm)

31
Q

Define meiosis

A

-2part Cell division that produces 4 haploid daughter cells from diploid cells

32
Q

What are the two functions of meiosis in sexual reproduction

A

Keeping the number of chromosomes, constant and increasing genetic variability

33
Q

What does meiosis 1 do and what are the stages?

A

Separates homologues

-prophase I; chromosomes condense, synapsis occur’s, crossing over takes place
-metaphase I; homologous pairs lineup,
Spindle fibre from one pole attaches to one member of each pair, opposite pole, attaches to homologue
-Anaphase I; homologous pairs separate to opposite ends
-telophase I and cytokinesis; one member of each homologous pair is that each pole, forms two haploid daughter cells, each chromosome consists of two chromatids 

34
Q

What does meiosis II do and what are the stages?

A

Separates sister chromatids

-Prophase ii; chromosomes in both daughter cells condense
-Metaphase ii; chromosomes, line up at equator
-Anaphase ii; centromere’s of sister chromatids separate, chromatids of each pair are called chromosomes, they moved to opposite poles
-Telophase ii; one complete set of chromosomes at each pole, cytokinesis occurs in both daughter cells making four haploid daughter cells

35
Q

Define nondisjunction

A

Mistake in cell division where homologous chromosomes or sister chromatids, failed to separate during anaphase 

36
Q

Nondisjunction in meiosis I result ?

A

2 abnormal daughter cells and 2normal daughter cells

37
Q

Nondisjunction in meiosis ii result,

A

One abnormal daughter cell and three normal daughter cells

38
Q

Define trisomy

A

If there’s an abnormality in cell division, resulting in an extra chromosome, face a presence of three copies of a chromosome instead of the normal two
Eg DS

39
Q

Define Monosamy

A

A gamete missing a copy of one chromosome; one chromosome copy instead of normal two

40
Q

Common phenotypes found in different and aneuploidy disorders
-Turner syndrome
-Klinefelter
-downs

A

-turners; individuals who have only a single X chromosome (XO); female,thick fold of skin on the neck, is shorter, wide chest, breasts & ovaries under her developed
-kline; males who are XXY; testes remain small and does not produce enough testosterone, taller than average, less muscular, facial and body hair under developed, breasts may develop
-downs; severe mental impairment, poor skeletal growth, flattened nose, forward tongue, slanted eyes, heart defects

BIO (4 decks)

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