Tag: inherited changes

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Questions Related to inherited changes

Multiple choice expression of gene inherited changes biology

Inducible operons differ from repressible operons in that

  1. operator of inducible operons is switched off by a repressor protein

  2. inducible operons have an operator that controls binding of RNA polymerase to the promoter region

  3. inducible operons use activators and positive control to regulate their transcription

  4. inducible operons usually include structural genes that function in catabolic pathways
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The inducible operon is usually off and it can be induced in the presence of inducer like lactose. After getting induced, the operon is turned on and transcription takes place to catabolize these inducers. Hence, the inducible operon is usually involved in catabolism. 

While repressible operon is on normally and results in transcription of structural genes to produce the desired product for e.g. tryptophan. Hence, it works at times when the bacterial cell does not require these products like tryptophan and the presence of tryptophan from external source turns off this operon. 
So, the correct option is 'inducible operons usually include structural genes that function in catabolic pathways'.

Multiple choice expression of gene inherited changes biology

Choose the correct answer from the alternatives given :
Repressible operon system is usually found in (i) pathways. The pathways end product serves as a (ii) to activate the repressor, turn off enzyme synthesis and prevent overproduction of the end product of the pathway. Genes for this operon are usually switched (iii) and the repressor is synthesised in an (iv) form.

  1. (i) anabolic, (ii) corepressor, (iii) on, (iv) - inactive

  2. (i) anabolic, (ii) inducer, (iii) off, (iv) - active

  3. (i) catabolic, (ii) inducer, (iii) off, (iv) - active

  4. (i) catabolic, (ii) corepressor, (iii) on, (iv) - inactive
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Repressible operons are generally involved in anabolic pathways, or the synthesis of an essential component, while inducible operons are generally involved in catabolic pathways or the breakdown of a nutrient. Positive control of an operon is when gene expression is stimulated by the presence of a regulatory protein. The repressible operon work on the feedback inhibition mechanism which is the phenomenon where the output of a process is used as an input to control the behavior of the process itself and the co-repressor serves as to activate the repressor. Genes of a repressible operon are switched off as they are required to synthesize the structural/functional genes in the absence of the repressor. The presence of the repressor can stop this process and hence the repressor is present in the inactive form. 

So, the correct option is '(i) anabolic, (ii) corepressor, (iii) on, (iv) - inactive'.

Multiple choice zoology inherited changes compatibility of blood groups blood group blood groups and compatibility advance

Several copies of genes carrying the contrasting characters are mainly included in which of the following laws?

  1. Law of independent assortment

  2. Law of segregation

  3. Multiple allelism

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Alleles are alternative forms of a gene. They are responsible for differences in phenotypic expression of a given trait. When a gene exists in three or more allelic forms it is called multiple allele. 
For example, ABO blood group system in humans is controlled by three alleles  I$^A$, I$^B$, and  I$^O$
IA and IB are codominant and make type A and type B antigens, respectively. IO is the recessive allele and produces no antigen.The blood groups arising from the different possible genotypes is given below.
Genotype                         Blood Group
I$^A$ I$^A$                        A
I$^A$ I$^O$                       A
I$^B$ I$^B$                        B
I$^B$ I$^O$                       B
I$^A$ I$^B$                      AB
I$^O$ I$^O$                      O
So, the correct answer is 'Multiple allelism'
Multiple choice zoology inherited changes compatibility of blood groups blood group blood groups and compatibility advance

Multiple alleles are situated at 

  1. Homologous chromosme at same locus

  2. Homologous chromosome at different locus

  3. Non-homologous chromosome at different locus

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Alleles are alternative forms of a gene. They are responsible for differences in phenotypic expression of a given trait. When a gene exists in three or more allelic forms it is called multiple allele. Homologous chromosomes are chromosome pairs, one from each parent. They are similar in length, gene position and centromere location. Multiple alleles are situated in homologous chromosome at the same locus. Thus the correct answer is option A.

Multiple choice zoology inherited changes compatibility of blood groups blood group blood groups and compatibility advance

If both parents are albino, all the offspring shall be

  1. Albino

  2. Some albino, some normal

  3. Homozygous normal

  4. Heterozygous normal
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Albinism is a autosomal genetical recessive gene disorder. It occurs in homozygous recessive state. The gene for albinism is a. it does not produce the enzyme tyrosinase, but is normal Allele A is does. Thus only homozygous individuals (aa) is affected. When both parents are albinic, all the offsprings also albinic generally.

So, the correct option is ‘Albino’.

Multiple choice zoology inherited changes compatibility of blood groups blood group blood groups and compatibility advance

When the heterozygote in a population have a reproductive advantage, one can predict that _________________.

  1. They will produce only heterozygous offspring

  2. The individuals that are homozygous recessive will take over

  3. Both homozygous dominant and homozygous recessive individuals will continue to appear in future generations

  4. Homozygous dominant and homozygous recessive individuals will be completely eliminated
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When heterozygotes have a selective or reproductive advantage (overdominance or heterozygote advantage), alleles for both dominant and recessive traits are maintained in the gene pool, ensuring both homozygous genotypes continue to appear in future generations.

Multiple choice zoology inherited changes compatibility of blood groups blood group blood groups and compatibility advance

Multiple gene inheritance takes into account ______________.

  1. Discontinuous traits

  2. Continuous traits

  3. Co-dominance

  4. Incomplete dominance
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Multiple gene inheritance, also known as polygenic inheritance, involves traits controlled by two or more genes that typically show a continuous range of variation (continuous traits) rather than distinct categories.

Multiple choice biology inherited changes linkage and crossing over linkage and recombination genetics: inheritance

The primary biological importance of sex in organisms is that it

  1. Is essential for organismic reproduction

  2. Is essential for cellular reproduction

  3. Causes new mutations to occur in offspring

  4. Promotes genetic variability in offspring
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The primary biological advantage of sexual reproduction over asexual reproduction is the generation of genetic diversity through recombination and independent assortment, which aids in adaptation.

Multiple choice biology inherited changes linkage and crossing over linkage and recombination genetics: inheritance

P is the daughter of Q. R has only two children - P and S. T is the brother of U. S is married to V. R has only two daughters. X is the father of Q. T is married to P. W is married to X. R is the son of Y. Who among the following is the mother of Q?

  1. W

  2. Y

  3. R

  4. X
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

X is the father of Q. W is married to X. Therefore, W is the mother of Q.

Multiple choice biology inherited changes linkage and crossing over linkage and recombination genetics: inheritance

A DNA molecule measures 204 nm in length; 35% of the molecule has AT base pairs. Find out the number of H-bonds existing between the two strands of DNA.

  1. 1590

  2. 159

  3. 1410

  4. 141
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA length 204 nm = 600 base pairs (0.34 nm/bp). 35% AT = 210 AT pairs (2 H-bonds each = 420). 65% GC = 390 GC pairs (3 H-bonds each = 1170). Total = 420 + 1170 = 1590.