MOD D

Question 1

What do chromosomes look like in a cell

Answer 1

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

Question 2

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

Answer 2

46, 23

Question 3

Number of choromosomes in meiosis phases

Answer 3

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

Question 4

Define meiosis

Answer 4

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

Question 5

Where does meiosis occur in females and males

Answer 5

Ovaries and testes

Question 6

Define chromosome

Answer 6

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

Question 7

Define genes

Answer 7

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

Question 8

Define somatic cells 

Answer 8

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

Question 9

Define diploid

Answer 9

Any cell with two of each kind of chromosome

Question 10

Define sex chromosome

Answer 10

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

Question 11

Define autosomes

Answer 11

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

Question 12

Define mitosis

Answer 12

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

Question 13

Define cell cycle

Answer 13

Two major phases interphase and cell division

Question 14

Define interphase

Answer 14

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

Question 15

What are the three parts of interphase?

Answer 15

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

Question 16

Define chromatin

Answer 16

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

Question 17

Define centromere

Answer 17

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)

Question 18

Define chromatid

Answer 18

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

Question 19

What is the G0 stage

Answer 19

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

Question 20

What are the two conditions for cell division?

Answer 20

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

Question 21

Define cytokinesis

Answer 21

-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

Question 22

What are the four stages of mitosis

Answer 22

Prophase metaphase, anaphase telophase

Question 23

Define prophase

Answer 23

-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

Question 24

Define metaphase

Answer 24

-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

Question 25

Define anaphase

Answer 25

-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

Question 26

Define telophase

Answer 26

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

Question 27

Define Karyotypes

Answer 27

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

Question 28

Why are karyotypes used?

Answer 28

-Diagnostic purposes -structure &# of chromo

Question 29

What do somatic cells contain?

Answer 29

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

Question 30

Define haploid

Answer 30

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

Question 31

Define meiosis

Answer 31

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

Question 32

What are the two functions of meiosis in sexual reproduction

Answer 32

Keeping the number of chromosomes, constant and increasing genetic variability

Question 33

What does meiosis 1 do and what are the stages?

Answer 33

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 

Question 34

What does meiosis II do and what are the stages?

Answer 34

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

Question 35

Define nondisjunction

Answer 35

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

Question 36

Nondisjunction in meiosis I result ?

Answer 36

2 abnormal daughter cells and 2normal daughter cells

Question 37

Nondisjunction in meiosis ii result,

Answer 37

One abnormal daughter cell and three normal daughter cells

Question 38

Define trisomy

Answer 38

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

Question 39

Define Monosamy

Answer 39

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

Question 40

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

Answer 40

-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