biology MCQs - 12th class Chapter 01 Mcqs

1

The protection of the internal environment from the harms of fluctuations in the external environment is termed as what?

A

Osmoregulation

B

Excretion

C

Homeostasis

D

Thermoregulation

2

The mechanism of regulation of solute and the gain and loss of water between an organism and its environment is called what?

A

Excretion

B

Osmoregulation

C

Anhydrobiosis

D

Thermoregulation

3

Which of these is NOT one of the three components of a living control system?

A

Receptor

B

Effector

C

Stimulus

D

Control centre

4

An environment that is more concentrated than the cell's internal environment is termed as what?

A

Hypotonic

B

Isotonic

C

Hypertonic

D

Aquatic

5

Plants that are adapted to live in habitats with a moderate water supply are known as what?

A

Hydrophytes

B

Xerophytes

C

Halophytes

D

Mesophytes

6

In which type of plants are stomata found on the upper surface of the leaves to promote water loss?

A

Xerophytes

B

Mesophytes

C

Hydrophytes

D

Cacti

7

Animals whose body fluid concentrations are kept isotonic to the external environment are known as what?

A

Osmoregulators

B

Osmoconformers

C

Homeotherms

D

Poikilotherms

8

Which chemical is retained by some cartilaginous fishes to protect against the damaging effects of high urea concentrations?

A

Ammonia

B

Uric Acid

C

Trimethylamine oxide (TMAO)

D

Creatinine

9

Fresh water protozoa like Amoeba and Paramecium pump out excess water using what structures?

A

Flame cells

B

Nephridia

C

Gills

D

Contractile vacuoles

10

The ability of some terrestrial animals to tolerate dehydration is known as what?

A

Anhydrobiosis

B

Metabiosis

C

Osmosis

D

Hydrolysis

11

In plants, leaves that are destined to fall off and carry accumulated wastes are called what?

A

Photosynthetic organs

B

Excretophores

C

Stomata

D

Hydathodes

12

The removal of the amino group from an amino acid is a process called what?

A

Deamination

B

Amination

C

Transamination

D

Denitrification

13

Which nitrogenous waste is the most toxic and requires the most water for its excretion?

A

Urea

B

Uric Acid

C

Ammonia

D

Creatine

14

How much water is required to excrete 1 gram of nitrogen in the form of urea?

A

1 ml

B

500 ml

C

100 ml

D

50 ml

15

Animals that excrete uric acid as their primary nitrogenous waste are called what?

A

Ammonotelic

B

Ureotelic

C

Uricotelic

D

Aminotelic

16

The simple tubular excretory system in flatworms like Planaria is called what?

A

Metanephridium

B

Malpighian tubule

C

Kidney

D

Protonephridium

17

The beating of cilia in which cells propels interstitial fluid into the tubular system of a Planaria?

A

Flame cells

B

Nephrostome cells

C

Epithelial cells

D

Gland cells

18

The excretory system in an earthworm, which has an internal ciliated opening, is called what?

A

Protonephridium

B

Metanephridium

C

Malpighian tubule

D

Kidney

19

The internal ciliated opening of the earthworm's excretory system is known as the what?

A

Nephridiopore

B

Flame cell

C

Nephrostome

D

Ureter

20

In insects, which tubular structures remove nitrogenous waste from the hemolymph?

A

Kidneys

B

Nephridia

C

Flame cells

D

Malpighian tubules

21

In insects, where does the final reabsorption of salts and water occur?

A

Midgut

B

Hindgut

C

Rectum

D

Stomach

22

What is the basic functional structure in the kidneys of vertebrates?

A

Neuron

B

Alveolus

C

Nephron

D

Villus

23

Which organ is considered the central station of metabolism and the body's central metabolic clearing house?

A

Kidney

B

Liver

C

Pancreas

D

Spleen

24

The metabolic pathway for the production of urea in the liver is called the what?

A

Krebs cycle

B

Glycolysis

C

Ornithine cycle

D

Urea cycle

25

In the urea cycle, one ammonia molecule combines with carbon dioxide and ornithine to form what?

A

Arginine

B

Urea

C

Citrulline

D

Alanine

26

The human urinary system consists of a pair of kidneys, ureters, a urinary bladder, and a what?

A

Urethra

B

Pelvis

C

Cortex

D

Medulla

27

The central cavity of the kidney where urine is collected before passing to the ureter is the what?

A

Cortex

B

Medulla

C

Pelvis

D

Hilus

28

Nephrons arranged along the border of the cortex and medulla, looping deep into the inner medulla, are called what?

A

Cortical nephrons

B

Medullary nephrons

C

Juxtamedullary nephrons

D

Pelvic nephrons

29

The cup-shaped swelling at the inner end of each nephron is called what?

A

Glomerulus

B

Loop of Henle

C

Collecting duct

D

Bowman's capsule

30

Blood enters the glomerulus through which vessel?

A

Efferent arteriole

B

Afferent arteriole

C

Renal vein

D

Peritubular capillary

31

The filtrate that appears in the Bowman's capsule is called what?

A

Urine

B

Plasma

C

Glomerular filtrate

D

Serum

32

The process where useful constituents of the glomerular filtrate are returned to the blood is called what?

A

Filtration

B

Secretion

C

Reabsorption

D

Excretion

33

Which hormone, released from the posterior pituitary, promotes water reabsorption in the collecting tubules?

A

Aldosterone

B

Insulin

C

ADH (Antidiuretic hormone)

D

Thyroxine

34

The mechanism that causes a gradual osmotic outflow of water from the filtrate in the descending loop of Henle is called what?

A

Active transport

B

Counter-current multiplier

C

Negative feedback

D

Positive feedback

35

A high level of circulating calcium in the blood, which can lead to kidney stones, is known as what?

A

Hyperoxaluria

B

Hypercalcemia

C

Uremia

D

Anemia

36

What is the most common type of kidney stone, accounting for 70% of cases?

A

Uric acid stones

B

Struvite stones

C

Calcium phosphate stones

D

Calcium oxalate stones

37

The non-surgical technique that uses shock waves to break up kidney stones is called what?

A

Dialysis

B

Lithotripsy

C

Catheterization

D

Ureteroscopy

38

A condition of high plasma levels of urea and other nitrogenous wastes due to nephron destruction is known as what?

A

Renal failure

B

Kidney stones

C

Anemia

D

Hypercalcemia

39

The type of dialysis that involves cleaning the blood using a machine with an artificial kidney is called what?

A

Peritoneal dialysis

B

Lithotripsy

C

Hemodialysis

D

Catheterization

40

Special proteins synthesized by plants during heat stress to prevent enzyme denaturation are called what?

A

Antibodies

B

Heat-shock proteins

C

Phytochromes

D

Albumins

41

How do plants adapt to cold stress to maintain cell membrane fluidity?

A

By decreasing solute concentration

B

By increasing the proportion of saturated fatty acids

C

By increasing the proportion of unsaturated fatty acids

D

By forming ice crystals in the protoplasm

42

Animals whose body temperature tends to fluctuate with the ambient temperature are known as what?

A

Homeotherms

B

Endotherms

C

Poikilotherms

D

Heterotherms

43

Which classification is for animals that generate their own body heat through metabolism, such as birds and mammals?

A

Ectotherms

B

Poikilotherms

C

Endotherms

D

Heterotherms

44

Which of the following is an example of a behavioral adaptation for thermoregulation?

A

Having a layer of blubber

B

Panting to cool down

C

Ground squirrels moving to burrows in midday heat

D

Raising fur to trap air

45

An increase in metabolic heat production through muscle contraction or movement is called what?

A

Non-shivering thermogenesis

B

Shivering thermogenesis

C

Evaporative cooling

D

Vasoconstriction

46

A thick layer of insulating fat under the skin of marine mammals like whales is called what?

A

Pelage

B

Brown fat

C

Adipose tissue

D

Blubber

47

In the human body, the homeostatic thermostat that regulates temperature is located in which part of the brain?

A

Cerebellum

B

Medulla oblongata

C

Cerebrum

D

Hypothalamus

48

What is the normal set point for human body temperature?

A

35°C

B

39°C

C

37°C

D

40°C

49

Chemicals called pyrogens, produced during infections, cause fever by doing what?

A

Lowering the hypothalamic set point

B

Increasing blood flow to the skin

C

Displacing the hypothalamic set point to a higher temperature

D

Activating sweat glands

50

In which part of the nephron does most of the reabsorption of useful substances occur?

A

Loop of Henle

B

Distal tubule

C

Proximal tubule

D

Collecting duct