Physiology of Organisms: Interactive Quizzes for Sixth Form Biology

Question 1

In a negative feedback mechanism, which component identifies a change in the body's internal environment?

Accepted Answer

Receptor

Answer

Control center

Answer

Effector

Answer

Stimulus

Question 2

Which characteristic is NOT a feature of negative feedback mechanisms?

Accepted Answer

Exaggeration of the initial change in the variable

Answer

Reversal of the variable to its original set point

Answer

Involvement of a receptor, control center, and effector

Answer

Common occurrence in biological systems

Question 3

In a negative feedback loop, the response aims to:

Accepted Answer

Counteract the initial change, bringing the variable back to its set point.

Answer

Amplify the initial change, causing the variable to move further away from its set point.

Answer

Remain independent of the initial change, having no impact on the variable.

Answer

Only occur in plants, not in animals.

Question 4

Identify the negative feedback mechanism in the human body:

Accepted Answer

Insulin release in response to high blood glucose

Answer

Oxytocin release during childbirth

Answer

Adrenaline release in response to stress

Answer

Prolactin release in response to breastfeeding

Question 5

Which of the following mechanisms does NOT involve negative feedback?

Accepted Answer

Stimulation of uterine contractions during childbirth

Answer

Regulation of blood glucose level by insulin secretion

Answer

Control of body temperature through sweating

Answer

Control of heart rate by baroreceptors

Question 6

Which organ in the endocrine system is not involved in hormone production and secretion?

Accepted Answer

Liver

Answer

Hypothalamus

Answer

Adrenal gland

Answer

Thyroid gland

Question 7

Which component is NOT essential to a negative feedback loop?

Accepted Answer

Positive feedback

Answer

Receptor

Answer

Control center

Answer

Effector

Question 8

Unlike negative feedback mechanisms, which characteristic is unique to positive feedback mechanisms?

Accepted Answer

Enhances the initial stimulus

Answer

Reverses the initial change

Answer

Employs sensors, control centers, and effectors

Answer

Opposes the initial change

Question 9

Which of the following is NOT an example of a negative feedback mechanism in the human body?

Accepted Answer

Adrenaline release in response to stress

Answer

Regulation of body temperature

Answer

Control of blood glucose levels

Answer

Regulation of blood pressure

Question 10

Which hormone is responsible for regulating blood pressure and electrolyte balance?

Accepted Answer

Aldosterone

Answer

Adrenaline

Answer

Testosterone

Answer

Insulin

Question 11

Which of the following is NOT an example of a negative feedback mechanism that helps maintain homeostasis?

Accepted Answer

Stimulation of gastric acid secretion by gastrin

Answer

Regulation of blood glucose levels by insulin and glucagon

Answer

Regulation of body temperature by sweating and shivering

Answer

Regulation of blood pressure by the kidneys

Question 12

Which hormone is primarily responsible for regulating blood sugar levels?

Accepted Answer

Insulin

Answer

Adrenaline

Answer

Thyroxine

Answer

Estrogen

Question 13

When faced with stressful situations, which hormone is secreted by the adrenal gland?

Accepted Answer

Epinephrine

Answer

Insulin

Answer

Thyroxine

Answer

Glucagon

Question 14

When blood glucose levels drop, which hormone is secreted by the pancreas to raise them?

Accepted Answer

Glucagon

Answer

Insulin

Answer

Epinephrine

Answer

Progesterone

Question 15

Which of the following is NOT a primary function of the circulatory system?

Accepted Answer

Producing white blood cells

Answer

Distributing oxygen and nutrients to bodily cells

Answer

Maintaining body temperature through heat distribution

Answer

Transporting waste products like carbon dioxide to the lungs and kidneys for elimination

Question 16

Which of the following is NOT an example of a negative feedback loop?

Accepted Answer

Gastrin stimulating gastric acid secretion

Answer

Insulin and glucagon regulating blood glucose levels

Answer

Sweating and shivering regulating body temperature

Answer

Sympathetic and parasympathetic nervous systems regulating heart rate

Question 17

Which of the following illustrates a positive feedback mechanism?

Accepted Answer

Releasing oxytocin during childbirth

Answer

Maintaining body temperature

Answer

Regulating blood glucose levels

Question 18

Which component is absent from a negative feedback loop?

Accepted Answer

Positive feedback

Answer

Receptor

Answer

Control center

Answer

Effector

Question 19

When the body faces stress, which hormone is released by the adrenal glands?

Accepted Answer

Epinephrine

Answer

Insulin

Answer

Thyroxine

Answer

Glucagon

Question 20

Which hormone, produced by the anterior pituitary gland, regulates overall body growth and metabolism?

Accepted Answer

Growth hormone (GH)

Answer

Oxytocin

Answer

Antidiuretic hormone (ADH)

Answer

Prolactin

Question 21

When an organism encounters a stressful situation, which hormone is primarily secreted by the adrenal glands to trigger the 'fight-or-flight' response?

Accepted Answer

Epinephrine (adrenaline)

Answer

Cortisol

Answer

Insulin

Answer

Thyroxine

Question 22

What is the main function of the diaphragm during respiration?

Accepted Answer

Create a pressure difference for air to enter the lungs

Answer

Control the rate of oxygen intake

Answer

Exchange gases between the blood and lungs

Answer

Filter harmful particles from the air

Question 23

Which of the following is NOT a function of the peripheral nervous system?

Accepted Answer

Integrating sensory information to generate responses

Answer

Transmitting motor commands to muscles

Answer

Relaying sensory information to the brain

Answer

Regulating involuntary bodily functions

Question 24

Which part of the nephron is responsible for filtering blood and removing waste?

Accepted Answer

Bowman's capsule

Answer

Collecting duct

Answer

Loop of Henle

Answer

Proximal convoluted tubule

Question 25

When plant roots encounter a physical barrier, they exhibit a growth response called:

Accepted Answer

Thigmotropism

Answer

Phototropism

Answer

Hydrotropism

Answer

Geotropism

Question 26

Which hormone in the human endocrine system is directly responsible for regulating calcium levels, affecting bone metabolism, muscle function, and nerve conduction?

Accepted Answer

Parathyroid hormone

Answer

Insulin

Answer

Epinephrine

Answer

Glucagon

Question 27

In the central nervous system, which structure is responsible for processing sensory information, controlling voluntary movement, and performing higher-level thinking?

Accepted Answer

Cerebrum

Answer

Cerebellum

Answer

Hippocampus

Answer

Medulla Oblongata

Question 28

When blood glucose levels rise, which hormone is released by the pancreas to regulate them?

Accepted Answer

Insulin

Answer

Epinephrine

Answer

Glucagon

Answer

Thyroxine

Question 29

In humans, insulin plays a crucial role in regulating blood glucose levels. Which of the following statements accurately describes how insulin contributes to this process?

Accepted Answer

Insulin enables cells, particularly in the liver and muscles, to absorb glucose from the blood, where it is stored as glycogen.

Answer

Insulin stimulates the liver to release glucose into the bloodstream, raising blood glucose levels.

Answer

Insulin prevents the pancreas from producing glucagon, which would otherwise release glucose from the liver.

Answer

Insulin triggers the breakdown of glycogen in the liver, releasing glucose into the bloodstream.

Question 30

Which hormone is responsible for controlling blood sugar levels?

Accepted Answer

Insulin

Answer

Thyroid Stimulating Hormone (TSH)

Answer

Epinephrine

Answer

Growth Hormone (GH)

Question 31

During breastfeeding, what is the main reason oxytocin is released in response to suckling?

Accepted Answer

To release milk from the mammary glands.

Answer

To produce milk in the mammary glands.

Answer

To control the baby's blood pressure and heart rate.

Answer

To strengthen the emotional connection between mother and baby.

Question 32

Which physiological process enables an organism to maintain a stable internal environment despite changes in the external environment?

Accepted Answer

Homeostasis

Answer

Thermoregulation

Answer

Osmoregulation

Answer

Feedback

Question 33

Which feature enables capillaries to facilitate the exchange of substances?

Accepted Answer

Thin walls

Answer

Thick walls

Answer

Large diameter

Question 34

Which tropism is responsible for plant growth in the direction of light?

Accepted Answer

Phototropism

Answer

Hydrotropism

Answer

Geotropism

Answer

Thigmotropism

Question 35

What is the main function of cytokinins in plants?

Accepted Answer

Promoting cell division and growth

Answer

Inhibiting seed germination

Answer

Stimulating chlorophyll production

Answer

Regulating plant water uptake

Question 36

What sets skeletal muscle apart from other muscle types?

Accepted Answer

Voluntary control

Answer

Branched appearance

Answer

Intercalated discs

Answer

Found in the heart

Question 37

When faced with stress, which hormone is primarily released by the adrenal glands, triggering the 'fight-or-flight' response?

Accepted Answer

Epinephrine (Adrenaline)

Answer

Insulin

Answer

Thyroxine

Answer

Glucagon

Question 38

How do negative feedback mechanisms help maintain homeostasis in living organisms? Provide specific examples to illustrate your answer.

Accepted Answer

Negative feedback mechanisms continuously monitor changes in a variable and trigger responses that counteract the change, keeping it within a narrow range.

Answer

Negative feedback mechanisms only activate when large changes occur, relying on significant adjustments to bring the variable back to its set point.

Answer

Negative feedback mechanisms amplify changes in the variable, making homeostasis difficult to maintain.

Answer

Negative feedback mechanisms are only found in plants, not in animals.

Question 39

How does the nervous system coordinate responses to external stimuli? Explain the roles of sensory receptors, neurons, and muscles in this process.

Accepted Answer

The nervous system receives sensory input, processes it, and generates motor output to muscles, coordinating responses.

Answer

The nervous system only transmits sensory information to the brain, which then independently generates motor output.

Answer

The nervous system only generates motor output, while sensory receptors independently receive and process information.

Question 40

Explain the specific roles of xylem and phloem in transporting substances within a plant.

Accepted Answer

Xylem transports water and minerals from roots to leaves, while phloem transports food from leaves to other plant parts.

Answer

Xylem transports nutrients from leaves to roots, while phloem transports water from roots to leaves.

Answer

Both xylem and phloem transport water and nutrients throughout the plant.

Answer

Xylem transports only water, while phloem transports only nutrients.

Question 41

How are neurotransmitters released at the synapse?

Accepted Answer

Synaptic vesicles containing neurotransmitters fuse with the presynaptic membrane, releasing their contents into the synaptic cleft.

Answer

Neurotransmitters are released directly from the presynaptic neuron's cell body.

Answer

Neurotransmitters pass through ion channels in the presynaptic membrane.

Answer

Neurotransmitters are released by the postsynaptic neuron in response to a signal from the presynaptic neuron.

Question 42

Which factor does NOT affect the rate of enzyme-catalyzed reactions?

Accepted Answer

Light intensity

Answer

Temperature

Answer

Substrate concentration

Answer

pH

Question 43

What is the primary function of the villi in the small intestine?

Accepted Answer

To maximize the surface area for nutrient absorption

Answer

To produce enzymes involved in digestion

Answer

To store digested nutrients until needed

Answer

To regulate the flow of blood to the intestine

Question 44

Which hormone is primarily responsible for regulating glucose levels in the blood?

Accepted Answer

Insulin

Answer

Epinephrine

Answer

Glucagon

Answer

Testosterone

Question 45

What is the process by which gases are exchanged between the lungs and the bloodstream called?

Accepted Answer

Diffusion

Answer

Osmosis

Answer

Active transport

Answer

Facilitation

Question 46

What is the primary role of the pancreas in the digestive system?

Accepted Answer

To produce digestive enzymes

Answer

To secrete bile into the small intestine

Answer

To absorb nutrients from food

Answer

To neutralize stomach acid

Question 47

Which of the following is the fundamental unit of the nervous system?

Accepted Answer

Neuron

Answer

Synapse

Answer

Reflex arc

Answer

Sense organ

Question 48

What is the primary function of stomata in plant leaves?

Accepted Answer

To facilitate gas exchange

Answer

To absorb water and minerals

Answer

To store food reserves

Answer

To synthesize chlorophyll

Question 49

Which of the following is a characteristic of endothermic animals?

Accepted Answer

They can maintain a constant body temperature

Answer

They rely on external sources to regulate temperature

Answer

They lay eggs as the primary mode of reproduction

Answer

They have a relatively short lifespan compared to ectotherms

Question 50

What is the primary significance of the seed coat in plants?

Accepted Answer

To protect the embryo from damage

Answer

To provide nourishment to the developing embryo

Answer

To aid in seed dispersal

Answer

To control the process of seed germination

Question 51

Which blood vessel carries blood away from the heart to the lungs?

Accepted Answer

Pulmonary artery

Answer

Aorta

Answer

Pulmonary vein

Answer

Vena cava

Question 52

What is crucial for maintaining a stable internal environment within an organism?

Accepted Answer

Negative feedback mechanisms

Answer

Active transport of ions across cell membranes

Answer

Rapid enzyme-catalyzed reactions

Answer

Hormonal regulation of blood glucose

Question 53

Which component is NOT part of a negative feedback mechanism?

Accepted Answer

Positive feedback

Answer

Receptor

Answer

Control centre

Answer

Effector

Question 54

Which hormone is responsible for the 'fight-or-flight' response in humans?

Accepted Answer

Adrenaline

Answer

Insulin

Answer

Thyroxine

Question 55

Which of the following is NOT a component of a negative feedback mechanism?

Accepted Answer

Positive feedback

Answer

Receptor

Answer

Control center

Answer

Effector

Question 56

Gas exchange in mammals primarily occurs through which structure?

Accepted Answer

Lungs

Answer

Trachea

Answer

Diaphragm

Answer

Bronchi

Question 57

Which type of blood vessel carries oxygenated blood away from the heart?

Accepted Answer

Arteries

Answer

Capillaries

Answer

Veins

Answer

Venules

Question 58

What is the process by which food is broken down into smaller molecules known as?

Accepted Answer

Digestion

Answer

Absorption

Answer

Assimilation

Answer

Egestion

Question 59

Which hormone is primarily responsible for stimulating the development of secondary sexual characteristics in males?

Accepted Answer

Testosterone

Answer

Estrogen

Answer

Progesterone

Answer

Luteinizing hormone

Question 60

The sympathetic nervous system is primarily responsible for which of the following responses?

Accepted Answer

Preparing the body for 'fight or flight' responses

Answer

Slowing down heart rate

Answer

Promoting digestion

Answer

Regulating body temperature

Question 61

Describe allosteric enzyme regulation and explain its importance in controlling metabolic pathways.

Accepted Answer

Allosteric regulation involves specific molecules binding to enzymes, affecting their activity and the metabolic pathways they control.

Answer

Allosteric regulation causes permanent structural changes in enzymes, altering their function.

Answer

Allosteric regulation is exclusive to prokaryotic cells.

Answer

Allosteric regulation plays no role in regulating metabolic pathways.

Question 62

Compare the structural differences and contrasting functions of xylem and phloem in transporting substances in plants.

Accepted Answer

Xylem, with thickened vessels, transports water and minerals upward; phloem, with sieve tubes and pores, transports sugars downward.

Answer

Phloem transports water and nutrients, while xylem transports sugars.

Answer

Xylem and phloem have identical structures and functions.

Question 63

Which blood component is responsible for carrying oxygen around the body?

Accepted Answer

Red blood cells

Answer

Platelets

Answer

White blood cells

Answer

Plasma

Question 64

Which mechanism is responsible for the movement of air in and out of the lungs during human respiration?

Accepted Answer

Diaphragmatic and intercostal muscle contractions

Answer

Pulmonary circulation

Answer

Diffusion

Answer

Ciliary action