MDCAT Past Papers - Biology - UHS

501. According to endosymbiosis theory flagella may have derived by ingestion of prokaryotes similar to

Amoeboid
Aerobic bacterium
Spirochete
Spirillum

502. Kidneys perform their osmoregulatory role under the effect of Antidiuretic Hormone, which type of urine is produced in this situation?

Hypotonic urine with decreased volume
Hypotonic urine with increased volume
Hypertonic urine with decreased volume
Hypertonic urine with increased volume

503. Which part of brain controls transition between sleeping and wakefulness?

Medulla oblongata
Cerebellum
Cerebrum
Pons

504. Which part of the brain contains central chemoreceptors that monitor CO2 levels in blood?

Pons
Midbrain
Hypothalamus
Medulla oblongata

505. Which component of a reflex arc connects the sensory neuron to the motor neuron within the spinal cord?

Receptor
Effector
Muscle fiber
Associative neuron

506. The 9.3.3.1 ratio of law of independent assortment can be affected by

Genetic drift
Small population
Gene linkage
Gene duplication

507. Best description of the process of crossing over during meiosis:

Duplication of chromosome
Exchange of genes between non-sister chromatids
Movement of chromosome to opposite poles
Separation of sister chromatids

508. Total number of linkage groups in a normal human is:

02
23
46
92

509. Nissis granule is a specialized structure in neuron formed by modification of:

Golgi bodies & Smooth ER
Peroxisome & Nitochondria
Lysosome & Vacuole
Ribosoma & Rough ER

510. What is the function of a centromere?

To protect the ends of chromosomes
To hold sister chromatids together
To carry genetic information
To initiate DNA replication

511. All are the functions of lysosome EXCEPT:

Intra cellular digestion
Removal of the waste
Autophagy
Lipid synthesis

512. The first consequence of lymphatic blockage in tissues is:

Deficiency of oxygen
Loss of nerve signals
Drop in blood pressure
Excess fluid accumulation in tissue

513. Which of the following is the auditory relay Centre and Centre that controls reflex movement of eyes?

Forebrain
Cerebellum
Midbrain
Cerebellum

514. Which of the following is the correct pathway of nerve impulse?

Receptors--- CNS--- Effectors
Effectors--- Receptors --- CNS
CNS--- Effectors--- Receptors
Effectors --- CNS --- Receptors

515. The neurotransmitters are secreted by the neuron from:

Axon ends
Dendrite end
Nissl's granules
Cell body

516. Hippocampus plays an important role in the:

Formation of short-term memory
Formation of image on retina
Formation of long-term memory
Formation of emotions

517. Enzymes activity decreases at very low or high pH because:

Substrate concentration increases
Enzymes become denatured
Product formation increases
Temperature becomes constant

518. The complementary base pairing in DNA is important because it:

Maintains the tertiary structure of enzymes
Provides energy for all cell metabolism
Enables protein to fold properly
Allows DNA act as a genetic blueprint during replication

519. A mature duplicated chromosome consists of:

Two identical double helical DNA molecules
Two different double helical DNA molecules
A double helical DNA molecule distributed in both chromatids
Histone chains wrapped around DNA core

520. The most primitive respiratory process occurring in a living cell is

Lactic acid fermentation
Alcoholic fermentation
Glycolysis
Krebs's cycle