SCORE SET B 15/12/2020

SCORE SET B 15/12/2020

SELECTED QUESTIONS

Multiple Choice

Bacteria do not have organelles; yet, the same reactions that take place on the mitochondria inner membrane, the phosphorylation of ADP to ATP, and chloroplasts, photosynthesis, take place in bacteria. Where do these reactions take place?

• These reactions take place in the nucleoid of the bacteria

• These reactions occur in the cytoplasm present in the bacteria

• These reactions occur at the inward side of the cell membrane of bacteria

• These reactions take place in the mesosomes.

For phosphorylation of ADP to ATP (cellular respiration), the inward side of

cell membrane known as mesosomes. The inward side of cell membrane

where photosynthesis occurred known as photosynthetic membrane.

Multiple Choice

What happens to the proteins that are synthesized on free ribosomes in the cytoplasm? Do they go through the Golgi apparatus?

• These proteins move through the Golgi apparatus and enter in the nucleus

• These proteins go through the Golgi apparatus and remain in the cytosol

• The proteins do not go through the Golgi apparatus and move into the nucleus for processing

• The proteins do not go through the Golgi apparatus and remain free in the cytosol

If the protein is targeted for secretion, membrane fixation or use in lysosomes,  the ribosome becomes bound to the ER and protein produced must go  through the Golgi apparatus. If the protein is targeted for intracellular  use within the cytosol, the ribosome remains free and unattached and the  protein produced do not go through the Golgi apparatus.

Multiple Choice

In a fruit fly experiment, grey body, normal winged (homozygous dominant) fruit flies were mated with black body, short winged (homozygous recessive) fruit flies. The F1 dihybrid females were then used in a test cross. If the genes are always linked and no crossing over occurs, what would be the predicted ratio in the F2 generation?

• A. 9 : 3 : 3 : 1

• B. 1 : 1 : 1 : 1

• C. 3 : 1

• D. 1 : 1

grey body and normal winged (GV/GV) crossed with black body, short winged  (gv/gv) produce F1 progeny with GV/gv. GV/gv crossed with gv/gv without no crossing over  will produce F2 generation with genotype 1GV/gv and 1 gv/gv.

Multiple Choice

Which of the following statements is/are the reason of alleles segregate independently of other alleles?

I. maternal and paternal chromosomes line up randomly on either side of the equator during metaphase I

II. crossing over during prophase I

III. separation of sister chromatids during anaphase I

• I and II only

• I and III only

• I and III only

• I, II and III

The physical basis of the independent assortment of chromosomes is the random  orientation of each bivalent chromosome along the metaphase plate in Metaphase I with respect to the other  bivalent chromosomes. Along with crossing over, independent assortment increases genetic diversity by  producing novel genetic combinations.

Multiple Choice

Which of the following crosses are expected to produce progeny of which half are homozygotes and the other half are heterozygotes?

I. HH X Hh

II. Hh X Hh

III. Hh X hh

• I & II

• I & III

• II & III

• I, II,& III

- HH x Hh produces 1HH(heterozygotes) and 1Hh(homozygotes) 

- Hh x Hh produces 1HH(homozygotes) and 2Hh(heterozygotes) 1hh(homozygotes)

- Hh x hh produces 2Hh (heterozygotes) and 2 hh (homozygotes)

Multiple Choice

A test cross of linked genes was performed with fruit flies (Drosophila melanogaster)

BbWw crossed with bbww

The resulting offspring were :

952 wild type body, normal wings

948 black body, vestigial wings

200 wild type body, vestigial wings

198 black body, normal wings

Which of the following statements explain for these results not fitting the expected ratio?

I. Crossing-over

II. Non-disjunction

III. Linkage gene

• I & II

• I & III

• II & III

• I, II & III

this is not mutation that cause from non- disjunction of chromosomes. This is linked  gene because resulting offspring produce 952 wild type body, normal wings and 948 black body,  vestigial wings which both of them were parental phenotypes with higher number of progeny  compared to the recombinant phenotypes 200 wild type body,vestigial wings and 198 black body,  normal wings with reduced in number of progenies.

Multiple Choice

Which of the following explain how autopolyploid can arise?

I Failure of chromosome segregation during meiosis may produce diploid gametes.

II A gamete from tetraploid organism fertilizes a gamete from diploid organism of the same species.

III A diploid gamete is fertilized by a normal haploid gamete, a triploid zygote is formed.

• I & II

• I & III

• II & III

• I, II & III

Multiple Choice

Which of the following is true about the vectors used in recombinant DNA technology?

• The vector must be able to replicate and dissolve inside the host cell.

• Pili is an example of the vector.

• Cosmid, a type of vector, is the combination of phage DNA and plasmids.

• The vector can only accept bacterial/phage DNA fragments.

A) The vector must be able to replicate and dissolve inside the host cell. (Description: vector does not dissolve inside the host cell.) 

B) Pili is an example of the vector. 

(Description: pili involve in conjugation process) 

C) Cosmid, a type of vector, is the combination of phage DNA and plasmids.

D) The vector can only accept bacterial/phage DNA fragments. 

(Description: vector can accept any donor DNA)

Multiple Choice

A gene carried by recombinant DNA is cloned when

• its host bacterium divides by binary fission

• it is transcribed

• it is fragmented by restriction enzyme

• it is hybridized

A) its host bacterium divides by binary fission 

(Description: binary fission is a asexual reproduction for bacterium) 

B) it is transcribed 

(Description: transcription only to produce mRNA) 

C) it is fragmented by restriction enzyme 

(Description: not relate to clone) 

D) it is hybridized

Multiple Choice

The figure below shows the hormone levels of the four hormones in a female reproductive cycle. The following questions 8 and 9 are based on figure below. Choose the INCORRECT statement about relationship between the different hormones involved during the 28 days.

• Days 1 to 12 - oestrogen gradually increases and peaks approximately on the 12th day. Progesterone, LH and FSH stay approximately at the same levels and begin to increase slightly from around day 12.

• FSH and LH patterns are very similar and peak during ovulation at approximately 14 days during this cycle. They drop sharply on day 15 and stay constant until day 28.

• Estrogen drops during days 13 and 14, and progesterone continues to gradually increase until about day 21, when it slowly beings to decrease again. Estrogen mirrors this shape and also has a second lower peak at about day 21.

• Days 1-5 is when menstruation occurs and the lining of the uterus is shed. Days 5-14 the uterus lining is repair and thicker when progestrone levels rise . Day 14 is when ovulation occurs caused by high levels of the hormone LH. If the woman is not pregnant the progesterone levels fall and the the uterus lining is shed. Another menstrual cycle starts.

Multiple Choice

The figure below shows the hormone levels of the four hormones in a female reproductive cycle. The following questions 8 and 9 are based on figure below. Choose the INCORRECT statement about relationship between the different hormones involved during the 28 days.

• Days 1 to 12 - oestrogen gradually increases and peaks approximately on the 12th day. Progesterone, LH and FSH stay approximately at the same levels and begin to increase slightly from around day 12.

• FSH and LH patterns are very similar and peak during ovulation at approximately 14 days during this cycle. They drop sharply on day 15 and stay constant until day 28.

• Estrogen drops during days 13 and 14, and progesterone continues to gradually increase until about day 21, when it slowly beings to decrease again. Estrogen mirrors this shape and also has a second lower peak at about day 21.

• Days 1-5 is when menstruation occurs and the lining of the uterus is shed. Days 5-14 the uterus lining is repair and thicker when progestrone levels rise . Day 14 is when ovulation occurs caused by high levels of the hormone LH. If the woman is not pregnant the progesterone levels fall and the the uterus lining is shed. Another menstrual cycle starts.

Multiple Choice

In DNA hybridization, the hybrid is formed of

• one double stranded DNA and one single stranded RNA molecule

• two double stranded DNA molecules

• two single stranded DNA molecules

• one single stranded DNA and one single stranded RNA molecule

A) one double stranded DNA and one single stranded RNA molecule (Description: not relate to DNA hybridization) 

B) two double stranded DNA molecules 

(Description: not relate to DNA hybridization) 

C) two single stranded DNA molecules 

D) one single stranded DNA and one single stranded RNA molecule (Description: not relate to DNA hybridization)