Tag: biology

Quizzes (1160) Questions (12174)

Questions Related to biology

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction.

  1. Calcium

  2. Magneisum

  3. Sodium

  4. Potassium
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Calcium is the ion released into the sarcoplasma from sarcoplasmic reticulum during the polarisation.  Ca++ attaches to the Troponin-C. This brings a confirmational change in the tropomyosin. As a result unmasking of active sites on actin for myosin takes place. Cross bridges are formed between actin and myosin. This results in muscle contraction.

Magnesium is used in phosphorylation reactions involving ATP.
Sodium and potassium help in maintaining the membrane potential.
So the correct option is A.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Calcium ions bring about muscle contraction through

  1. Activation of myosin ATP-ase

  2. Exposing active sites of actin filaments

  3. Mobilisation of food reserve

  4. Both A and B
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • The muscle contraction cycle is triggered by calcium ions binding to the protein complex troponin, exposing the active-binding sites on the actin. 
  • ATP can then attach to myosin, which allows the cross-bridge cycle to start again; further muscle contraction can occur. 
  • Cardiac myosin activators stimulate myosin ATPase, thereby increasing force generation. Hence, Calcium ions bring about muscle contraction
  • through Activation of myosin ATP-ase.
 So, the correct answer is 'Activation of myosin ATP-ase'.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Organ of Golgi is the sensing structure formed at the junction of

  1. Two nerves

  2. Two bones

  3. Nerve and muscle

  4. Muscle and tendon
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Organ of Golgi. also known as Golgi tendon organ is a kind of proprioreceptor that sense stimulus within the body. It receives information from the tendons and sense tension in muscles. These kind of receptors get activated when the muscles stretch or contract due to any activity. These receptor are made up of collagen strands and formed at the junction of muscle and tendon.
So, the correct answer is 'Muscle and tendon'.
Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

During strenuous muscular activity, hydrogens removed from sugar molecules are accepted temporarily by .......... to form..........        

  1. oxygen; water

  2. pyruvate; lactic acid

  3. myoglobin; carbaminohaemoglobin

  4. oxygen; carbon dioxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During the strenuous muscular activity, hydrogens removed from sugar molecules are accepted temporarily by pyruvate to form lactic acid.

So, the correct option is 'pyruvate; lactic acid'.

Multiple choice biology movement and locomotion in man locomotion in animals bones and movements muscle contraction

The term "innominate" is used for?

  1. A bone and an artery

  2. A bone and a vein

  3. A bone and a nerve

  4. A vein and a nerve
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The term innominate means unnamed or anonymous. It is often used to refer to certain anatomical structures that have a descriptive name rather than precise ones. In humans this termed is used to refer to the hip bone and brachiocephalic artery.
Hence, the correct answer is 'A bone and an artery'.

Multiple choice biology movement and locomotion in man locomotion in animals bones and movements muscle contraction

An example of chitinous exoskeleton is

  1. Oriole

  2. Sea stars

  3. Clam

  4. Honeybee

  5. Earthworm
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • A tough, semitransparent substance that is the main component of the exoskeletons of arthropods, such as the shells of crustaceans and the outer coverings of insects(honey bee). 
  • Chitin is also found in the cell walls of certain fungi and algae. Chemically, it is a nitrogenous polysaccharide (a carbohydrate). Hence, An example of a chitinous exoskeleton is Honeybee.
So, the correct answer is 'Honeybee'.