Consider the following statements about DNA replication.
I. A replisome is the largest functional unit in DNA replication factories.
II. RNA polymerase complexes are responsible for transcribing the newly synthesised RNAs into their mature form.
III. DNA polymerases add new deoxyribonucleotides to the 3' end of a DNA strand.
IV. A replication bubble is a region of single stranded DNA that arises due to unwinding of DNA in same direction by primase
Choose the incorrect statement(s)
I and II
III and IV
I, II and IV
I, II, III and IV
The process in which mature differentiated cells reverse to meristematic activity to form callus is called
redifferentiation
dedifferentiation
cyto-differentiation
differentiation
Endothecium and tapetum are formed from
primary sporogenous tissue
primary parietal layer
primary parietal layer and sporogenous tissue respectively
sporogenous tissue and primary parietal layer respectively
Which of the following is an example of a defence used by plants against herbivorous?
I. Production of caffeine, tannin, quinine.
II. More production of non-woody tissues.
III. Production of hairs, thorns, spines.
IV. Production of hormones like chemicals that interfere with insect metamorphosis.
Select the correct codes
I and II
II, III and IV
I, II and III
I, III and IV
Embryo rescue is resorted to
obtain new generation of plants quickly
to reduce chance of seedling growth
ensure growth of interspecific hybrids
induce somaclonal variations
In sweet pea, C and P genes are essential for flower colour. In absence of either or both the genes, the flowers are white. What will be the percentage of coloured flowers in the offspring of cross Ccpp x ccPp?
75%
25%
80%
50%
Apomictic embryos in citrus arise from
synergids
maternal sporophytic tissue in ovule
antipodal cell
haploid cell
Following are the statements regarding sexual reproduction in flowering plants.
I. Parthenium is a plant that causes pollen allergy.
II. If tapetum is destroyed, then unfeasible male gametophytes are produced.
III. Egg apparatus has 3 synergids and 2 antipodal cells.
IV. Megaspore is the first cell of gametophytic generation.
Choose the incorrect option.
I and II
II and III
III and IV
I and IV
Reproductive isolation mechanism prevent interbreeding of naturally sympatric population. Given below are categories of isolating mechanisms. Choose the correct name for isolation when potential mates occupy overlapping ranges but reproduce at different times of the year.
Ecological isolation
Behavioural isolation
Temporal isolation
Mechanical isolation
A women with albinic father marries an albinic man. The proportion of her progeny is
2 normal : 1 albinic
All normal
All albinic
1 normal : 1 albinic
D.
1 normal : 1 albinic
Albinism is an autosomal recessive metabolic disorder. It is characterised by the complete or partial absence of pigment in the skin, hair and eyes due to the absence or defect of tyrosinase, a copper-containing enzyme involved in the production of melanin.
An albino man (rr) marries a normal women (RR). Their progeny carries one recessive allele (r) and one dominant allele (R), i.e. it is heterozygous. When this heterozygous daugther (Rr) marries albinic man (rr), the proportion of her progeny found out to be 1 albino and 1 normal.