SESSION 2021-22
SAMPLE PAPER
CLASS – XI SUBJECT: BIOLOGY
MAX. MARKS: 35 TIME ALLOWED: 2 HOURS
General Instructions:
i) All questions are compulsory.
ii) The question paper has three sections and 13 questions. All questions are compulsory.
iii) Section – A has 6 questions of 2 marks each; Section- B has 6 questions of 3 marks each; Section- C has a case study-based question of 5 marks.
iv) There is no overall choice. However, internal choice has been provided in some questions. A student has to attempt only one of the alternatives in such questions.
v) Wherever necessary, neat and properly labelled diagram should be drawn.
SECTION – A
1. A vegetative cell of a plant undergoes equational division and produces 128 daughter cells, Calculate the number of Mitotic cycles had the original single cell undergoes.
6 Mitotic Cycles
OR
How does cytokinesis of plant and animal cell differ from each other?
In plant cells, wall formation starts in the centre of the cell and grows outward to meet the existing lateral walls
In an animal cell, this is achieved by the appearance of a furrow in the plasma membrane.
2. Name the plant growth hormones which are specific to perform following roles-a- Bolting (internode elongation just prior to flowering).
Gibberellin
b- The apical bud supresses the growth of lateral buds.
Auxin
3. a- How does function of RUBISCO enzyme affected by concentration of O2 and CO2?
In higher O2 concentration acts as oxygenase.
In higher CO2 concentration acts as Carboxylase.
b- Mention the process in which Oxygen is evolved during light reaction of photosynthesis.
Photolysis of water
4. During oxidative phosphorylation in mitochondria how many NADH + H+ and FADH2 are produced?
6 NADH + H+
2 FADH2
OR
Write the steps of Glycolysis where –
a- ATP is consumed
ATP is consumed
Glucose Glucose-6 -Phosphate
Fructose 6 Phosphate Fructose 1, 6 bisphosphate
b- ATP is formed
2 Phosphoglycerate Phosphoenol pyruvate
Phosphoenol pyruvate Pyruvate
5. In muscles some actin and myosin are main filamentous proteins which carries out muscle contraction. Identify any two from the given diagram-
Labelling of any two
a- Troponin
b- Tropomyosin
c- F- actin
6. Explain resting potential (Polarization state) of a neuron.
Resting potential of neuron
i- Sodium – potassium pump (transport 3 Na+ outwards and 2 K+ inwards
ii- Outer surface of axonal membrane has positive charge and inner side has
negative charge
iii- The electric difference across the membrane is called as polarised state (resting potential)
(Any two relevant points)
SECTION B
7. Chemiosmotic hypothesis during photophosphorylation is based on concentration gradient of H+ ion. Explain the process of formation of such gradient in chloroplast.
i- Photolysis of water causes accumulation of proton ions in side lumen
ii- During Electron transport the carriers push proton in side lumen
iii- Accumulation of proton ion inside lumen.
8. Identify the stages of Meiotic – I cell division in which following events occur-
a- Synapsis formation
Zygotene
b- Formation of recombinant nodule
Pachytene
c- Termination of Chiasmata
Diakinesis
9. Expand ECG and give diagrammatic representation of ECG. Also illustrate the meaning of any two peak/ waves obtained during ECG.
ECG- Electrocardiogram
Correct diagram (NCERT, Fig. 18.3, page no- 268)
P- Depolarization of atria
QRS- depolarization of ventricles
T- repolarization
10.
In the above diagram, comment on the functioning of A, B and C.
A- Air is exhaled from the lungs
B- Ribs muscles/ intercostal muscles moves inward and help in exhalation
C- Diaphragm muscles moves upward and help in exhalation
11. What changes occur to cytoplasmic Pyruvate under following conditions-
a- Anaerobic condition in muscle cells
Form Lactic acid
b- Anaerobic condition in presence of yeast
Form Alcohol
c- Aerobic condition
Enters into Mitochondria (Kreb’s Cycle)
12. What are different mode of excretion in animals. Give one example of each.
Mode of excretion-
1- Ammonotelic / excrete ammonia
Ex- Many bony fishes, aquatic amphibians (one example)
2- Ureotelic / excrete Uric acid
Ex- Birds, Reptiles, land snails (one example)
3- Ureotelic-/ excrete Urea
OR
Fill the A, B, C, D, E spaces by appropriate answer: –
A – Heart
B – Cause vasodilation (dilation of blood vessels) and thereby decrease the blood pressure.
– ANF mechanism, therefore, acts as a check on the renin-angiotensin mechanism
C – JuxtaGlomerular apparatus
D – Convert angiotensinogen, in to angiotensin I. to regulate blood pressure
– stimulate the glomerular blood flow and thereby the GFR back to normal. (any one role)
E – Pituitary Gland (Neurohypophysis)
F – facilitates water reabsorption from latter parts of the tubule, thereby p increases the glomerular blood flow and thereby the GFR. reventing diuresis) (any one role)
Ex- Mammalia (one example)
SECTION – C
13. Read the paragraph and answer the questions: –
The hormone is distributed in blood and binds to distant target cells. These chemical messengers control various functions like metabolism, reproduction, growth etc. the hormones may be of various types-
Protein hormones (e.g., insulin, glucagon), Steroids (e.g., cortisol, testosterone) etc.
Some secondary messengers also help in mechanism of action of hormones.
Hormone secretion is regulated by signals from the nervous system, chemical changes in the blood, and effect of other hormones.
(a) Endocrine action: the hormone is distributed in blood and binds to distant target cells.
(b) Paracrine action: the hormone acts locally by diffusing from its source to target cells in the neighbourhood.
(c) Autocrine action: the hormone acts on the same cell that produced it.
a- Diagrammatically represent the mechanism of action of peptide hormone (FSH).
Correct diagram (NCERT;Fig. 22.5 (a), Page no- 34)
b- Write any two differences between mechanism of action of protein and steroid hormones.
Protein hormone –
i- They interact with membrane bound receptors on plasma membrane
ii- They generate secondary messengers like cAMP, Ca++, etc
Steroid hormone
i- They interact with intracellular receptors
ii- Regulate gene expression
Or any two relevant answer.
OR
Your pituitary gland is about the size of a pea and is situated in a bony hollow, just behind the bridge of your nose. It is attached to the base of your brain by a thin stalk. The pituitary gland is often called the master gland because it controls several other hormone glands in your body, including the thyroid and adrenals, the ovaries and testicles. Together, the hypothalamus and pituitary tell the other endocrine glands in your body to make the hormones that affect and protect every aspect of your health. The pars distalis, pars intermedia and Pars nervosa are various parts of pituitary gland.
Answer the following questions-
a- What is role of LH and FSH in human female?
LH- help in ovulation
FSH- help in follicular development
b- What is pituitary dwarfism? Which hormone is responsible for this?
GH (Growth Hormone)
low secretion causes Pituitary dwarfism
c- Which pituitary hormone acts on Kidney? Also mention the role of that hormone.
Vasopressin / ADH (anti diuretic hormone)-
stimulates resorption of water and electrolytes by the distal tubules and
thereby reduces loss of water through urine (diuresis).