Science [2 Mark Questions]

Blood is called a fluid connective tissue because it develops from the mesoderm of the embryo like any other typical connective tissue and connects all the organ systems of the body by transporting oxygen, nutrients, hormones, etc., and removing wastes from these organs.

Saprophytic nutrition: It is that nutrition in which an organism obtains its food from dead organic matter of dead plants, dead animals and rotten bread.
Example: Fungi and many bacteria obtain food by saprophytic nutrition.

Plants do not move. In a large plant body there are many dead cells like sclerenchyma as a result it requires less energy as compared to animals.

Large organisms contain a respiratory pigment called haemoglobin which carries the oxygen from the lungs to all the body cells very efficiently.

It is necessary to separate oxygenated and deoxygenated blood in mammals and birds, because they need high energy and large amount of oxygen. The separation of oxygenated and deoxygenated blood provides high oxygen supply to the organs.

The organism in which the cell membrane acts as a respiratory surface is Amoeba. In amoeba, the unicellular animal, the exchange of gases takes place through the cell membrane or the plasma membrane. The cell membrane of amoeba absorbs oxygen from the surrounding area and release carbon dioxide by the process of diffusion.

Phloem transports food materials from the leaves to different parts of the plant. The transportation of food in phloem is achieved by utilizing energy from ATP which helps in creating osmotic pressure that transport food from the area of high concentration to low concentration.

Chlorophyll is vital for photosynthesis, which allows plants to absorb energy from light. Chlorophyll molecules are arranged in and around photosystems that are embedded in the thylakoid membranes of chloroplasts. In these complexes, chlorophyll serves three functions.

Respiratory substrates are those organic substances which are oxidised during respiration to liberate energy inside the living cells. The common respiratory substrates are carbohydrates, proteins, fats and organic acids. The most common respiratory substrate is glucose. It is a hexose monosaccharide.

Dialysis: The procedure used for cleaning the blood of a person by separating the urea from it is called dialysis. The patients with kidney failure are put on dialysis.

Bile or gall is a dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the digestion of lipids in the small intestine.
In humans, bile is produced continuously by the liver (liver bile), and stored and concentrated in the gallbladder.

The rate of breathing is slower in terrestrial organisms as compared to aquatic organisms. This is due to the fact that in water, the amount of oxygen is less as compared to air so, in aquatic organisms the rate of breathing is faster.

In lungs, the bronchioles terminate in balloon-like structures called alveoli. The alveoli contains network of blood capillaries that increase the surface area for exchange of gases.

A land plant may die if its roots remain water logged for a long time because too much water expels all the air from in - between the soil particles. Due to this, oxygen is not available to the roots for aerobic respiration. Under these conditions the roots will respire anaerobically producing alcohol which may kill the plant.

Holozoic nutrition: It is that nutrition in which an organism takes the complex organic food materials into its body by the process of ingestion the ingested food is digested and then absorbed into the body cells of the organism.
Example: Human beings obtain food by holozoic nutrition.

Ingestion refers to the consumption of food, water and other substances through the mouth into the gut. Ingestion is a general term used for taking in any substance into the digestive system.

The energy currency of the cell is ‘ATP’. It is produced in cytoplasm in lower organisms which respire anaerobically. In higher organisms, ‘ATP’ is produced in mitochondria when they respire aerobically.

It is necessary to separate the oxygenated blood from mixing with deoxygenated blood as mammals and birds have high energy needs because they constantly require energy to maintain their body temperature.

Renal artery, afferent arterioles, glomerulus, efferent arterioles, secondary capillaries.

Parasite: A parasite is an organism (plant or animal) which feeds on another living organism called its host.
Example: Plasmodium and round worm.

The basophils(a type of WBC) and mast cells present in our body(a part of formed elements) secrete an anti-coagulant known as Heparin. Blood doesn't clot in the blood vessels because of a chemical called heparin.Heparin is an anticoagulant which does not allow the blood to clot in the blood vessels.

Hemoglobin is the respiratory pigment present in humans Its main function is to transport oxygen to various parts of the body. Apart from oxygen transportation, hemoglobin has some role in transportation of carbon dioxide from body parts to lungs. About 10% of carbon dioxide transportation occurs through hemoglobin.
Carbon monoxide (CO) has a great affinity with haemoglobin. Increase in amount of CO in body can even cause the death of organism due to suffocation (insufficient blood supply).

A nutrient can be defined as a substance which an organism obtains from its surroundings and uses it as a source of energy or for the biosynthesis of its body constituents (like tissues and organs). The four important nutrients present in our food are: carbohydrates, fats, proteins and mineral salts.

In case of kidney failure, an artificial kidney is needed. The kidneys lose the ability to remove the nitrogenous waste products from the body or their activity is highly reduced. They fail to perform their vital function. There are many reasons for kidney failure such as injury, infection and reduced blood flow that lead to accumulation of wastes in our body. Hence, an artificial kidney can be used.

The kidney is responsible for the removal of waste products from the blood. Damage from accidents or disease can lead to a build-up of poisonous wastes in the body.The chemicals (toxic waste products) from the blood enter the dialyzing fluid through the process of diffusion when blood is passed along the tubes.

Phloem tissue is a vascular tissue which transports the food materials made in the leaves to the other parts of the plant. Phloem is made up of many cells joined end to end to form long tubes. The cells of the phloem are sieve tubes and companion cell. These are living cells.

Fungi are heterotrophic organisms. They get their nutrition by absorbing organic compounds from the environment. Fungi, along with bacteria that are found in soil, are the primary decomposers of organic matter in terrestrial ecosystems. They break down the food material outside their body by secreting digestive enzymes and absorb nutrition from it.

Blood is a red coloured liquid which circulates in our body. It is red because it contains a pigment called haemoglobin in its red cells.

Importance of soil for plant growth:

1. Soil provides the base on which a plant can grow.
2. Soil serves as reservoir of water for plants.
3. Soil serves as reservoir of different minerals which are essential for growth of plants.
4. Soil contains many organic materials which provide nutrients to plants.

The water required by the plants for photosynthesis is absorbed by the roots of the plants from the soil through the process of osmosis. The absorbed water is then transported upward through the xylem vessels to the leaves where it reaches the photosynthetic cells and utilized in photosynthesis.

Blood pressure: The pressure at which the blood is pumped around the body by the heart is called blood pressure. The two factors which expresses the blood pressure a person are systolic pressure and diastolic pressure.

The food of herbivores contains a huge amount of cellulose. The animals need the assistance of certain bacteria to digest cellulose and this process takes time. Due to this, herbivores have longer small intestine than carnivores. Meat is easier to digest and hence carnivores have small intestine which is much smaller than in herbivores.

The process by which green plants make their own food (like glucose) from carbon dioxide and water by using sunlight energy in the presence of chlorophyll is called photosynthesis.

1. Proteins.
2. Starch.
3. Proteins.
4. Fats.

A denosine triphosphate (ATP) is thought of as the "molecular currency" for energy transfer within the cell. Function: ATPs are used as the main energy source for metabolic functions. They are consumed by energy-requiring (endothermic) processes and produced by energy-releasing (exothermic) processes in the cell.

Urea is the main nitrogenous waste in human blood. It is removed from the body in the form of urine through the kidneys.

The conditions for photosynthesis are sunlight, chlorophy ll, carbon-dioxide and water.

The role of saliva in the digestion of food:

1. It moistens the food for easy swallowing.
2. It contains a digestive enzyme called salivary amylase, which breaks down starch into sugar.

The excretory system removes the poisonous waste substances from the body in the form of urine and maintains ionic balance called osmoregulation.

Anaerobic respiration takes place in human muscles during vigorous physical exercise because oxygen gets used up faster in the muscle cells than can be supplied by the blood.

1. Circulatory system.
2. Excretory system.
3. Respiratory system.
4. Digestive system.

The processes essential for maintaining life are:

1. Nutrition
2. Respiration
3. Transportation
4. Excretion.

When water is lost in the form of vapours through the stomata present on leaves, it is called transpiration. Some plants lose excess water in the form of liquid droplets from the margins of leaves, through hydathodes. This process is called as guttation. Hydathodes are structurally modified pores present on leaf margin.

In humans, lungs are the major respiratory organ.Internally, lungs are divided into numerous sac like structures called as alveoli. respiratory is the process that occurs between oxygen and carbon dioxide. Oxygen is passed from the lungs to the bloodstream and carbon dioxide is eliminated from the bloodstream to the lungs. Exchange of Gas takes place in lungs between the alveoli and capillaries which are tiny blood vessels, placed at the walls of alveoli. The rate of diffusion depends on the thickness of the biological membrane which forms the boundary between the external environment.

The process by which green plants make their own food from carbon dioxide and water by using sunlight energy in the presence of chlorophyll is called photosynthesis.
Plants make their own food in the presence of sunlight and hence they are autotrophs. Plants convert sunlight energy into chemical energy. They use carbon dioxide, water and sunlight to make their own food in the presence of chlorophyll.

If the blood pressure of a person is 120/80 it means that the systolic pressure is 120mm Hg and diastolic pressure is 80mm Hg.