Tag: botany

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Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

In pea plants, the long-stem trait $(L)$ is dominant and the short-stern trait $(I)$ is recessive. Two pea plants were crossed, producing seeds that yielded 165 long-stem plants and 54 short-stem plants. The genotypes of the parent plants were most likely

  1. $LI$ and $LL$
  2. $LI$ and $LI$
  3. $II$ and $II$
  4. $LL$ and $II$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  • The ratio of long stem plants to short stem plants among the progeny is 165:54 which means it has a ratio of 3:1. This ratio is possible if the parents are heterozygous in nature which after the cross will produce homozygous tall, heterozygous tall and homozygous dwarf offsprings. 
  • As the heterozygous offspring expresses the dominant allele, they will also be tall. This is a classic example of the monohybrid ratio that produces a ratio of 3:1 in the F2 generation of pure line parents.

So, the correct option is 'LI and LI'.

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

Gene library or DNA library has collection of

  1. DNA and RNA

  2. Any one type of gene of Organism

  3. c DNA only

  4. All possible genes of all organisms
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • A Gene library or DNA library is a comprehensive collection of cloned DNA fragments from a cell, tissue, or organism.
  • DNA libraries can be used to isolate a specific gene of interest as they generally include at least one fragment that contains the gene.
  • Hence Gene library or DNA library has a collection of c DNA only.
  • So, the correct answer is 'c DNA only'.
Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

When a cross is made between two parents with respect to a single character, it is called as

  1. Dihybrid

  2. Monohybrid

  3. Trihybrid

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • A monohybrid cross is a type of cross between two individuals with different alleles at one genetic locus of interest. 
  • The character(s) being studied in a monohybrid cross are governed by two or multiple alleles for a single locus.
  • A dihybrid cross is a cross between two pure lines (varieties, strains) that differ in two observed traits. In Mendelian sense, between the alleles of both these loci, there is a relationship of complete dominance - recessive.
  • Trihybrid cross is the mating of two individuals, organisms, or strains that have different gene pairs that determine three specific traits or in which three particular characteristics or gene loci are being followed.
Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

A cross in which a single pair of contrasting characters is studied at a time is called as_____________

  1. Monohybrid cross

  2. Dihybrid cross

  3. Trihybrid cross

  4. Tetrahybrid cross
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • A monohybrid cross is a mating between two individuals with different alleles at one genetic locus of interest. The cross involves a single pair of contrasting characters.

So, the correct answer is option A.
Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

Mendel formulated the law of purity of gametes on the basis of _______________

  1. Dihybrid cross

  2. Monohybrid cross

  3. Back cross

  4. Test cross
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The monohybrid cross-refers to inheritance of singe contrasting trait by two parents at a time. For example, a cross of tall (T) and dwarf (t) pea plants (TT x tt). Mendel observed that monohybrid cross between two pure breeding varieties yields $F _1$ generation which exhibits the dominant trait; although factor for a recessive trait is present in $F _1$ hybrids. Self-fertilization of $F _1$ generation obtains $F _2$ generation which exhibits both dominant and recessive traits in the 3:1 phenotypic ratio. This laid the foundation of the law of purity of gametes which states that the two factors for a trait, present together in a heterozygous individual, do not get mixed and are separated during gametogenesis. 
Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

A breeding experiment studying a single trait is 

  1. Monozygous

  2. Dizygous

  3. Dihybrid

  4. Monohybrid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Monohybrid cross refers to inheritance of a single contrasting trait by two parents at a time. For example, a cross of tall (T) and dwarf (t) pea plants (TT xtt). Dihybrid cross refers to inheritance of two pairs of contrasting characters by two parents at the same time. For example, a cross of two pea plants, one with yellow and round seeds (YYRR) and other with green and wrinkled seeds (yyrr). The term “monozygous” represents twins being developed from a single zygote. The first division in zygote produces two identical cells that independently develop into two embryos; monozygotic twins are produced. The term “dizygous” represent twins being developed from individual zygotes. Fertilization of two eggs by separate sperms produces two zygotes that independently develop into two embryos. Thus, the correct answer is the option D.

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

A husband and wife have normal vision but fathers of both of them were colour blind. Probability of their first daughter to be colour blind is

  1. 25%

  2. 50%

  3. 75%

  4. 0%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Probability of their first (or any) daughter being colourblind is nil as the daughter of normal father can never be colourblind.

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

Biological unit controlling heredity is ___________.

  1. Genome

  2. Chromosome

  3. Genotype

  4. Gene.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A.Genome – a set of chromosome in an organism in a body.

B.Chromosome – Dark coloured, small rod like structures, appear in the dividing nucleus is called Chromosome.

C.Genotype – It is the representation of an individual’s genetic constitution with respect to a single character or set of characters.

D.Gene - A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. However, many genes do not code for proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases.

So, the correct option is ‘Gene’.

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

According to modern concept, Mendel's factor is called as_____________

  1. Chromosome

  2. Gene

  3. DNA

  4. Chromatid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • According to the modern concept, Mendel's factor is called a gene. Mendel believed that heredity is the result of discrete units of inheritance, and every single unit (or gene) was independent in its actions in an individual’s genome. According to this Mendelian concept, inheritance of a trait depends on the passing-on of these units. For any given trait, an individual inherits one gene from each parent so that the individual has a pairing of two genes.
Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

What is the correct sequence from least complex to most complex in terms of the amount of information they carry?

I. Chromosomes
II. Base pair
III. Codon
IV. Gene

  1. I $\rightarrow $ II$\rightarrow $ III $\rightarrow $ IV
  2. II $\rightarrow $ III$\rightarrow $ I $\rightarrow $ IV
  3. III $\rightarrow $ II $\rightarrow $ I $\rightarrow $ IV
  4. II $\rightarrow $ III $\rightarrow $ IV $\rightarrow $ I
  5. II $\rightarrow $ IV $\rightarrow $ II $\rightarrow $ I
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A base pair (II) carries least information as at least three bases together (base triplet) make a codon (III) which in turn code for an amino acid. Genes (IV) are the stretch of DNA and each gene codes for a particular protein. Many genes are linearly arranged on a chromosome which means that chromosomes carry information for many proteins.

Therefore, the correct answer is option D.