Class 9th Biology Unit 9 Transport Importants Short Questions
Short And Simple Question And Answer
Q1: Why the cells are regarded as units of life?
Ans: Cells are the primary sites for metabolic processes. That is why they are regarded as the “units of life.
Q2: Why materials are transported to and from cells?
Ans: Complex metabolic reactions occur in living organisms. In order to run their metabolism.
cells need some materials from the environment and also need to place some materials into the environment. For this purpose, materials are transported to and from cells.
Q3: What is the limitation of phenomenon of diffusion for transport?
Ans: One method for the movement of molecule is diffusion but it alone cannot fulfill the needs. It takes much time for materials in solution to diffuse even a few inches.
Q4: Why diffusion can work efficiently in unicellular and simple multicellular organisms?
Ans: Diffusion can work only in unicellular and simple multicellular organisms because every corner of their body is in close and direct contact with the environment.
Q5: Why diffusion cannot work efficiently in complex multicellular organisms?
Ans: In complex multicellular bodies, cells are far apart from the environment and such bodies need a comprehensive system for the transport of materials.
Q6: What are the functions of roots in plants?
Ans: Functions of Roots:
In addition to anchor the plant, roots perform two other vital functions. First; they absorb water and salts from soil. Second; they provide conducting tissues for distributing these substances to the tissues of stem.
Q7: What is the difference between xylem and phloem tissues?
Ans: XYLEM TISSUE
Xylem tissue is responsible for the transport of water and dissolved substances from roots to aerial parts.
It consists of vessel elements and tracheids.
Phloem tissue is responsible for the conduction of dissolved organic matter (food) between different parts of plant body.
It consists of sieve tube cells and companion cells.
Q8: Discuss role of root hairs in plants for water and ion uptake.
Ans: Root hairs provide large surface area for absorption. They grow out into spaces between soil particles where they are in direct contact with water. The cytoplasm of root hairs has higher concentration of salts than soil water, so water moves by osmosis into toot hairs. Salts also enter root hairs by diffusion or active transport.
Q9: Define Transpiration?
Ans: Transpiration: Transpiration is the loss of water from plant surface through evaporation. This loss may occur through stomata in leaves, through the cuticle present on leaf epidermis, and through special openings called lenticels present in the stems of some plants.
Q10: Define stomatal transpiration?
Ans: Most of the transpiration occurs through stomata and is called stomatal transpiration. The mesophyll cells of leaf provide large surface area for the evaporation of water.
Q11: How air movement affects rate of transpiration?
Ans: Effects of Air Movement: Wind (air in motion) carries away the evaporated water from leaves and it causes an increase in the rate of transpiration from the surfaces of mesophyll. When air is still, the rate of transpiration is reduced.
Q12: Which factors affect the rate of transpiration?
Ans: Following are some important factors affecting the rate of transpiration:
Temperature,Air humidity,Air movement,Leaf surface area.
Q13: Why transpiration is known as necessary evil?
Ans: Transpiration is called a necessary evil. It means that transpiration is a potentially harmful process but is unavoidable too.
Transpiration may be a harmful process in the sense that during the conditions of drought, loss of water form plant results in serious desiccation, wilting and often death. On the other. hand, transpiration is necessary too. It creates a pulling force called transpirational pull which is principally responsible for the conduction of water and salts.
Q14: What is cohesion tension theory?
Ans: According to cohesion tension theory, the force which carries water (and dissolved materials) upward through the xylem is transpirational pull. Transpiration creates a pressure difference that pulls water and salts up from roots.
Q15: Define Transpiration pull?
Ans: “When one water molecule moves up in the xylem of the leaf, it creates a pulling force that continues all the way to root. This pulling force created by the transpiration of water is called transpirational pull”.
It also causes water move transversely (from root epidermis to cortex and pericycle).
Q16: What is the effect of water stress in plants?
Ans: There is strong evidence that even mild water stress results in reduced growth rate in plants.
Q17: What are reasons for creation of transpirational pull?
Ans: Following are the reasons for the creation of transpirational pull.
Water is held in a tube (xylem) that has small diameter.
Water molecules adhere to the walls of xylem tube (adhesion).
Water molecules cohere to cach other (cohesion).
Q18: llow food is transported in different parts of plants?
Ans: Transport of food is through pressure-flow mechanism. In pressure-flow mechanism, food is moved from sources to sinks.
Q19: What is difference between sources and sinks?
Sources include the exporting organs, typically a mature leaf or storage organ.
Sinks are the areas of active metabolism or storage e.g. roots, tubers, developing fruits and leaves, and growing regions.
A storage organ is capable of storing food and exporting the stored materials.
Root of beet is a sink in first growing season, but becomes source in next growing season, when sugars are utilized in the growth of new shoots.
Q20: Discuss direction of transport of food and salts in plants?
Ans: One way street:
Xylem is a one way street from roots to leaves for water and salts.
Two way Street:
Phloem is a two way street for food. The direction of the movement of food is decided by supply and demand in sources and sinks.
Q21: Give an example that plants need a lot of water?
Ans: Plants need a lot of water. Young Brassica plants take up an amount of water equal to their shoot weight in about 5 hours. If that applied to us, we would have to drink 3 gallons of water an hour to stay alive.
Q22: Which systems perform transport in humans?
Ans: Transport of different materials in human body is performed by two systems.
Blood circulatory system (Cardiovascular System)
The two systems are well coordinated and associated with each other.
Q23: What is a closed circulatory system?
It is a type of circulatory system in which the blood always remains in the blood vessels.
Humans and other vertebrates.
Q24: What is an open circulatory system?
It is a type of circulatory system in which blood does not remain in the blood vessels.
Invertebrates like arthropods. See ilm
Q25: What are the main components of human blood circulatory system?
Ans: The main components of human blood circulatory system are:
Q26: How is plasma separated from blood?
Ans: Blood is taken from an artery and an anti-coagulant (a chemical that inhibits blood clotting) is mixed in it. After about 5 minutes, plasma separates from blood cells, which settle down.
Q27: What do you know about blood?
Blood is a specialized body fluid (a connective tissue) that is composed of a liquid called blood plasma and blood cells. The weight of blood in our body is about 1/12th of our body. The average adult body has about 5 litres of blood.
Q28: Describe composition of plasma?
Ans: Composition of Plasma:
Plasma is primarily water in which proteins, salts, metabolites and wastes are dissolved. Water constitutes about 90-92% of plasma and 8-10% are dissolved substances. Salts make
up 0.9% of plasma, by weight. Proteins make 7-9% by weight of plasma. The important proteins present in plasma are antibodies, fibrinogen, albumin etc. Plasma also contains the digested food, nitrogenous wastes and hormones. Respiratory gases i.e. CO₂ and O₂ are present in the plasma.
Q29: Tell the number of RBCs in human blood?
A cubic millimeter of blood contains 5 to 5.5 million of RBCs in males,
A cubic millimeter of blood contains 4 to 4.5 million of RBCs in females.
Q30: What are the two different types of WBCs?
Ans: Types of WBCs:
There are two main types of WBCS:
(i) Granulocytes have granular cytoplasm. These include neutrophils, eosinophils and basophils.
(ii) Agranulocytes have clear cytoplasm and include monocytes and B and T lymphocytes.
Q31: What are Thrombocytes? Describe their function?
Ans: They are not cells, but are fragments of large cells of bone marrow, called megakaryocytes. They do not have any nucleus and any pigment.
One cubic millimeter of blood contains 250,000 platelets.
The average life span of a blood platelet is about 7 to 8 days. Platelets help in blood clotting. The clot serves as a temporary seal at the damaged area.
Q32: Illow pus is formed?
Ans: White blood cells die in the process of killing the germs. These dead cells accumulate and make the white substance called pus seen at the infection site.
Q33: What happens in dengue fever?
Ans: In dengue fever, there is a sharp decrease in the number of platelets in blood. Because of this, patients bleed from the nose, gums and under the skin.
Q34: What is leukaemia?
Ans: It is also called as blood cancer. Leukaemia is the production of great number of immature and abnormal white blood cells.
This is caused by a cancerous mutation (change in gene) in bone marrow or lymph tissue
cells. The mutation results in uncontrolled production of defective white blood cells
Q35: Write a short note on Thalassaemia?
Ans: It is also called Cooley’s anaemia on the name of Thomas B. Cooley, an American physician. It is a genetic problem due to mutations in the gene of haemoglobin. The mutation results in the production of defective haemoglobin and the patient cannot transport oxygen properly.
Q36: What is the incidence of thalassaemia in the world?
Ans: There are about 60-80 million people in the world who carry thalassaemia. India, Pakistan, and Iran are seeing a large increase in thalassaemia patients. Pakistan alone has 250,000 such patients. These patients require blood transfusions for life-time.
Q37: On what date International Thalassaemia day is celebrated? What is its aim?
Ans: The world celebrates the International Thalassaemia Day on 8th of May. This day is dedicated to raise public awareness about thalassaemia and to highlight the importance of the care for thalassaemia patients.
Q38: What is an antigen?
Ans: “A substance which stimulates the production of an antibody when introduced into the body, i.e. it can stimulate an immune response is called an antigen.”
Q39: What is the basis of blood group systems?
Ans: Blood group systems are a classification of blood based products on the presence or absence ee ilm. of antigens on the surface of red blood cells.
Q40: How many human blood groups systems have been studied till to date?
Ans: A total of 29 human blood group systems are now recognized by the International Society of Blood Transfusion (ISBT).
Q41: How many blood groups are there in ABO blood group system?
Ans: ABO Blood System:
In this system, there are four different blood groups which are distinct from each other on the basis of specific antigens (antigen A and B) present on the surface or RBCs.
Blood Group A:
A person having antigen A has blood group A.
Blood Group B:
A person having antigen B has blood group B.
Blood Group AB:
A person having both antigens has blood group AB.
Blood Group O:
A person having none of the A and B antigens has blood group O.
Q42: Define blood transfusion?
Ans: “Blood transfusion is the process of transferring blood or blood-based products from one
person into the circulatory system of another”
Blood transfusions can be life-saving in some situations, such as massive blood loss due to injury, or can be used to replace blood lost during surgery.
Q43: Why the blood of donor should be checked before transfusion?
Ans: A number of infectious diseases such as AIDS, Hepatitis B and C etc. can pass from the affected donor to the recipient. Before transfusion, the blood of donor is checked for germs etc.
Q44: What is universal donor?
Ans: Universal Donor:
O blood group individuals are called universal donors, because they can donate blood to the recipients of every other blood groups.
Q45: Who discovered Rh blood group system and also discuss its basis of classification.
In 1930’s Karl Landsteiner discovered the Rh-blood group system.
Types of blood groups:
In this system, there are two blood groups i.e. Rh-positive and Rh-negative. These blood groups are distinct from each other on the basis of antigens called Rh factors.
Q46: Differentiate between pericardium and pericardial fluid?
Heart is enclosed in a sac known as pericardium.
It helps in protection of heart muscles.
Pericardial fluid is a fluid present between pericardium and heart walls.
It reduces friction between pericardium and heart, during heart contractions.
Q47: Why heart is felt to be present on left side of our body?
Ans: The heart is usually felt to be on the left side because the left chamber of the heart i.e. left ventricle is stronger and has a thicker wall. It pumps blood to all body parts.
Q49: What is the mass and size of heart in normal adults?
Ans: In normal adults, the mass of the heart is about 250-350 grams, and its size is equal to a clenched fist.
Q50: How can we say that heart works as double pump?
Ans: Human heart works as a double pump. It receives deoxygenated (with less oxygen) blood from body and pumps it to lungs. At the same time, it receives oxygenated (with more oxygen) blood from lungs and pumps it to all body. Inside heart chambers, the deoxygenated and oxygenated bloods are kept separated.
Q51: Why the walls of the left ventricle are the thickest one?
Ans: The walls of the left ventricle are the thickest one. These are about a half inch thick. They have enough force to push blood into the body. This gives an evidence that the structures of the parts of heart are adaptive to their function.
52.Name and explain the valves present in
The opening between right atrium and right ventricle is guarded by a valve known as tricuspid valve (because it has 3 flaps).
At the base of pulmonary trunk, pulmonary semilunar valve is present in which prevents the backflow of blood from pulmonary trunk to right ventricle.
The opening between left atrium and left ventricle is guarded by a valve known as bicuspid valve (because it has two flaps).
Aortic semilunar valves
Q53: Define pulmonary circulation?
Ans: The pathway one which deoxygenated blood is carried from heart to lungs and in return oxygenated blood is carried from lungs to heart is called pulmonary circulation or circuit.
Q54: What is systemic circulation?
Ans: Systemic Circulation:
“The pathway on which oxygenated blood is carried from heart to body tissues and in return deoxygenated blood is carried from body tissues to heart is called systemic circulation or circuit”.
Q55: Justify that there is low blood pressure in pulmonary circulation?
Ans: The blood in pulmonary circulation is at lower pressure than the blood in systemic circulation. It gives sufficient time to blood for gaseous exchange in lungs.
Q56: What is meant by cardiac cycle? / Define heartbeat?
Ans: “The relaxation of heart chambers fills them with blood and contractions of chambers propels blood out of them. The alternating relaxation and contractions make up the cardiac cycle and one complete cardiac cycle makes one heartbeat”.
The total duration of cardiac cycle is 0.8 seconds.
Q57: Define cardiac diastole?
Ans: Cardiac diastole:
“Atria and ventricles relax and blood is filled in atria. This period is called cardiac diastole.”
The duration of cardiac diastole is 0.4 seconds.
Q58: Define systole and diastole. / What is difference between systole and diastole?
“The period of atrial and ventricular contraction is called systole.”
When Atria and ventricles relax blood is filled in atria. This period is called diastole.
Q59: How the sound of lubb dubh is produced during heart beat?
Ans: When ventricles contract, tricuspid and bicuspid valves close and “lubb” sound is produced. Similarly when ventricles relax, the semilunar valves close and “dubb” sound is produced. “Lubb-dubb” can be heard with the help of a stethoscope.
Q60: What is the average human heartbeat?
Ans: The average human heart beats 70 times/minute. So it would beat approximately 2.5 billion times during a life time of 66 years.
Q61: Define pulse?
Ans: “Pulse is the rhythmic expansion and contraction of an artery as blood is forced through it by the regular contractions of heart”.
Pulse can be felt at areas where artery is close to skin for example at wrist, neck, groin, or
top of foot. Most commonly, people measure their pulse in their wrist.
62.Write any two differences between arteries and veins?
Carry blood away from heart.
Carry blood towards heart.
Thick and elastic.
Thin and less elastic.
Q63: What is vascular surgery?
The field in surgery in which diseases of arteries and veins are managed by surgical methods is called vascular surgery.
A vascular surgeon treats diseases of all parts of blood circulatory system except that of heart and brain.
Q64: What is the contribution of Ibn-e-Nafees in the study of human blood circulatory system?
He is honored to be the first scientist who described the path way of blood circulation.
Q65: What is the contribution of William Harvey in the study of human blood circulatory system?
He discovered the pumping action of heart and the pathway of blood in major arteries and veins.
Q66: How heart muscles are supplied with blood?
Ans: Even though the heart chambers are continually bathed with blood, this does not nourish heart muscles. The blood supply to heart muscles is provided by coronary arteries, which emerge from the base of aorta. Heart muscles are drained by coronary veins, which empty into right atrium. Coronary arteries and veins are collectively called coronary circulation and it is a part of systemic circulation.
Q67: Write causes of cardiovascular disorders.
Ans: Causes of Cardiovascular disorders:
The causes that lead to cardiovascular disorders include:
Advanced age Diabetes
High blood concentration of low density lipids (e.g. cholesterol)
Tobacco smoking,High blood pressure,Obesity,Sedentary lifestyle
Q68: What is difference between atherosclerosis and arteriosclerosis?
It is commonly referred to as a “narrowing” of arteries.
It is a chronic disease in which there is accumulation of fatty materials, cholesterol, or fibrin in arteries.
It is a general term describing any hardening of arteries.
It occurs when calcium is deposited in the walls of arteries.
Q69: What is a silent heart attack?
Ans: Approximately one fourth of all myocardial infarctions are silent i.e. without chest pain or other symptoms. A silent heart attack is more common in the elderly, in patients with diabetes mellitus and after heart transplantation.
Q70: Define myocardial infarction?
Ans: The term myocardial infarction is derived from myocardium (the heart muscle) and infraction (tissue death). It is more commonly known as a heart attack. It occurs when blood supply to a part of heart is interrupted and leads the death of heart muscles.
Q71: What is Angioplasty and bypass surgery?
Angioplasty is a mechanical widening of a narrowed or totally obstructed blood vessels.
Bypass Surgery: Surgery in which arteries or veins from elsewhere in the patient’s body are grafted to the coronary arteries to improve blood supply to heart muscles.