Choater 15

Question 1

Chromosomes theory of inheritance

Answer 1

According to this theory, Mendelian gene have specific loci along chromosomes and it is the chromosomes that undergo segregation and independent assortment

Question 2

Wild type

Answer 2

The phenotypic character most commonly observed in natural populations,such as red eyes in Desophila is called wild type

Question 3

Mutant phenotype

Answer 3

Traits that are alternative to the wild type such as white eye in Drosophila are called mutant phenotype

Question 4

Female vs male genotype

Answer 4

XX chromosomes female

XY chromosomes male

Question 5

Sex-linked gene

Answer 5

A gene located on wither sex chromosomes

Question 6

X-linked chromosomes and y linked chromosomes

Answer 6

The human X chromosomes contains approximately 1100 gene,which are called X linked gene p, while those on Y chromosomes are Y linked

Question 7

Why is Y chromosomes only in male

Answer 7

Y chromosomes is passed along virtually intact from father to all his sons

Question 8

Inheritance of X linked chromosomes

Answer 8

Father pass X linked chromosome to all their but none to sons. In contrast, mother can pass X-linked allel to both sin and daughter

Question 9

Why will clink affect more males than females

Answer 9

Any male receiving the recessive allele from mother will express the trait. For this reason more male are affected

Question 10

Duchesses muscular dystrophy

Answer 10

Disease for weakening muscle and loss of coordination

Question 11

Hemophilia

Answer 11

An Xlinked recessive disorder defined by absence of one or more of the protein required for blood clotting

Question 12

X inactivation in female mammal

Answer 12

Female inherit two X chromosomes while male only inherit one. Therefore in female one X chromosomes is inactivated during early embryonic development.

Question 13

Barr body

Answer 13

The inactivation X in each cell of a female condenses into a computer object called Barr Body

Question 14

What happens if female is heterozygous?

Answer 14

If female is heterozygous for a sex linked trait. About half of her cell will express one allele who left other will express alternate

Question 15

Linked gene

Answer 15

Gene located near each other on the same chromosome tend to be inherited together in genetic crosses;such genes are called linked gene

Question 16

Genetic recombination

Answer 16

The production of off-spring with combination of traits that differ from those found in either P generation parent.

Question 17

What creates genetic variation

Answer 17

Meiosis, random fertilisation, independent assortment and crossing over

Question 18

Parental Type

Answer 18

Offspring that matches parents

Question 19

Recombinant type

Answer 19

The offspring that have new combinations are called recombinant type

Question 20

Crossing over

Answer 20

Accounts for the recombination of linked gene. a set of protein orchestrates an exchange of corresponding segment of one maternal and one paternal.. probability with chance of crossing over approximately equal at all point along chromosomes. The farther apart two gene, the higher the probability that a crossover will occur

Question 21

Genetic map

Answer 21

An ordered list of the genetic loci along particular chromosome

Question 22

Linkage map

Answer 22

A genetic map based on recombination frequencies is called a linkage map

Question 23

Map unit

Answer 23

Defining one map unit as equivalent to a 1% recombination frequency.

Question 24

Is crossing over uniform in length

Answer 24

No

Question 25

Non disjunction

Answer 25

In which the membrane of a pair of homologous chromosomes do not move apart properly during meiosis 1 or sister chromatid fail separate during meiosis 2. One gamete receive two chromosomes while other receive one.

Question 26

Aneuploidy

Answer 26

Abnormal number of chromosomes

Question 27

Monosomic

Answer 27

Missions chromosomes in the zygote; the aneuploid zygote is said to be monosomic

Question 28

Trisomic

Answer 28

If a chromosome is present in triplicate in the zygote , the aneuploid cell is trisomic for that chromosome.

Question 29

Polyploidy

Answer 29

Some organism have more than two complete chromosome in all somatic cells.

Question 30

Deletion

Answer 30

Occurs when fragment of DNA is lost

Question 31

Duplication

Answer 31

Producing a duplication of a portion of that chromosome

Question 32

Inversion

Answer 32

Reattach to the original chromosome but in reverse orientation

Question 33

Translocation

Answer 33

Fragment to join a non homologous chromosome, a rearrangement called translocation

Question 34

Down syndrome

Answer 34

One aneuploid condition Extra chromosome 21 as result 47 chromosomes Features of patient include facial features, short stature, correctable heart defect and developmental delay

Question 35

Aneuploid of sex chromosomes

Answer 35

An extra sex chromosomes in a male producing XXY- have male sex organ but testes are abnormally small and male is sterile -female with trisomy XXX are at risk of learning disabilities but are fertile . Also called Turner syndrome

Question 36

Disorder occur by structurally altered chromosomes

Answer 36

- eg Cri du cheat (cry like a cat) result from deletion of chromosome 5 - have small head with unusual feature and has a cry that sounds like a distress cat - eg chronic myelogenous leukaemia - the exchange of large portion of chromosome 22 with small fragment from tip of chromosome 9

Question 37

Genomic imprinting

Answer 37

Variation in phenotype depending on whether an allele is inherited from the male or female present is called genomic imprinting. Imprints are formed during gamete production with the result that one allele is not expressed in offspring.

Question 38

Do inheritance control trait come from mother or father

Answer 38

The inheritance of traits controlled by the gene present in mitochondria and plastid dependent on maternal parent because the zygote cytoplasm containing these organelle comes from the egg.