Mitosis And Meiosis

Question 1

During meiosis, sperm fall into two categories, half the sperm cells receive ——— and half received ———

Answer 1

X chromosome and Y chromosome

Question 2

Is X-Y system the only way to describe sexuality in organisms?

Answer 2

No. X-O system and Z-W system and haplo-diploid system also exist

Question 3

A gene on the Y chromosome ——— is required for the development of testes, without it, the gonads develop into ———

Answer 3

SRY- sex determining region of Y Ovaries

Question 4

Why are there X linked diseases more than Y linked diseases

Answer 4

More genes are encoded on the X chromosome, regarding Y linked genes,

The Y chromo- some is passed along virtually intact from a father to all his sons. Because there are so few Y-linked genes, very few disor- ders are transferred from father to son on the Y chromosome.

Question 5

Males are ———

Answer 5

the terms dominant and recessive do not apply to them

Question 6

Name a few of the X linked diseases

Answer 6

Red-green color blindness
Duschenne muscular dystrophy
A and B haemophilia

Question 7

Females have 2 X chromosomes while male only have one, how do they compensate this double dose?

Answer 7

Almost all of one X chromosome in females have been inactivated during early embryonic development. The inactive X——> becomes Barr body. In ovaries, however, Barr bodies chromosomes are reactivated in the cells that give rise to eggs, resulting in female gamete egg having an active X after meiosis

Question 8

Bar bodies lies along the ——— and because of it in females,

Answer 8

Barr body occurs randomly and independently in each embryonic cell present at the time of X inactivation. As a consequence, females consist of a mosaic of two types of cells: those with the active X derived from the father and those with the active X derived from the mothe

Question 9

crossing over is a random event, with the
chance of crossing over approximately equal at all points along a chromosome

Answer 9

True

the farther apart two genes are, the higher the prob-
ability that a crossover will occur between them and therefore the higher the recombination frequency

Question 10

Chromosome number of monopsony and trisomy

Answer 10

Monosomy- 2n-1
Trisomy - 2n+1

Question 11

Non dysjuntion in mitosis result in ———

Answer 11

Anueploid condition in a large number of somatic cells and likely to be passed along

Question 12

Polyploidy results from ———

Answer 12

the fertilization of an abnormal diploid egg produced by nondisjunction of all its chromosomes.

triploidy (3n) and tetraploidy (4n) indicate three and four chro- mosomal sets, respectively.

Question 13

Polyploidy in plants is dangerous for them.

Answer 13

False. Polyploidy plants are more robust and strong than normal eu-ploid species

Polyploid animal spe- cies are much less common, but there are a few fishes and amphibians known to be polyploid. In general, polyploids are more nearly normal in appearance than aneuploids. One extra (or missing) chromosome apparently disrupts genetic balance more than does an entire extra set of chromosomes.

Question 14

Alterations of chromosomes structure can be arisen by ——

Answer 14

1. Deletion
2. Duplication
3. Inversion
4. Translocation

Question 15

If the deleted segment binds to another sister or non sister chromatid——> ———

Answer 15

Duplication of a portion of that chromosome

Deletions and duplications are especially likely to occur dur- ing meiosis. In crossing over, nonsister chromatids sometimes exchange unequal-sized segments of DNA, so that one partner gives up more genes than it receives .products of such an unequal crossover are one chromosome with a deletion and one chromosome with a duplication.

Question 16

Translocation is like ——— but differs in that

Answer 16

Recombination during meiosis cross over. But translocation occurs in non homologous chromosome

Question 17

In inversions, ——— and ——— can exist as two forms

Answer 17

Pericentric and para centric

Question 18

Down syndrome is beacuse of ———

Answer 18

Trisomy 21, each cell contains total of 47 chromosomes.

Down syndrome includes characteristic facial features, short stature, correctable heart defects, and developmental delays. Individuals with Down syndrome have an increased chance of developing leukemia and Alzheimer’s disease but have a lower rate of high blood pressure, atherosclerosis (harden- ing of the arteries), stroke, and many types of solid tumors.

Question 19

Klinefelter syndrome - chromosome ====

Answer 19

XXY
Main ma san taw yaut kyr
Small testes, large breast, low rate of facial hair , infertility

Question 20

Triple X syndrome occurs in ———

Answer 20

Females

Taller than average, FERTILE but learning difficulties

Question 21

Monosomy is also called —— syndrome

Answer 21

Turner syndrome XO the only viable Monosomy, other Monosomy do not survive to birth , sterile do not mature sex organs

Question 22

Cri du chat syndrome is because of the deletion of chromosome ——

Answer 22

5p

Question 23

Translocation can cause cancer. T or F

Answer 23

True

Chromosomal translocations can also occur during mito- sis; some have been implicated in certain cancers, including chronic myelogenous leukemia (CML). This disease occurs when a reciprocal translocation happens during mitosis of cells that are precursors of white blood cells. The exchange of a large portion of chromosome 22 with a small fragment from a tip of chromosome 9 produces a much shortened, easily recog- nized chromosome 22, called the Philadelphia chromosome (Figure 15.16). Such an exchange causes cancer by creating
a new “fused” gene that leads to uncontrolled cell cycle pro- gression. (The mechanism of gene activation will be discussed in Chapter 18.)

Question 24

Genomic imprinting is checking ——-

Answer 24

Whether an allele is inherited by mom or dad

Question 25

All eukaryotic greens are located on the nuclear chromosome , t or false

Answer 25

False. Can also exist in organelles in the cytoplasm

They are called extranuclear genes or cytoplasmic genes.

Question 26

Mitochondria and chloroplast pass along their genes to offsprings

Answer 26

True

One plant——> color comes only from maternal parent . Turns out it was distributed by the plastids with different allele for a pigmentation genes

In most plants,
a zygote receives all its plastids from the cytoplasm of the egg and none from the sperm, which contributes little more than a haploid set of chromosomes. An egg may contain plastids with different alleles for a pigmentation gene. As the zygote develops, plastids containing wild-type or mutant pigmenta- tion genes are distributed randomly to daughter
cells

Question 27

Most of the mitochondrial gene help in ——

Answer 27

The products of most mitochondrial genes help make up some of the protein complexes of the electron trans- port chain and ATP synthase

Defect in these genes——> can reduce the synthesis of ATP

For example, mitochondrial myopathy causes weakness, intolerance of exercise, and muscle deterioration. Another mitochondrial disorder is Leber’s hereditary optic neuropathy, which can pro- duce sudden blindness in people as young as their 20s or 30s. The four mutations found thus far to cause this disorder affect oxidative phosphorylation during cellular respiration, a crucial function for the cell

Question 28

Both mitochondria and chloroplasts DNA are ———

Answer 28

Maternal inheritance