Life Processes

Flashcards about the different life processes in living organisms.

What is a key difference between living and non-living things?

Living things exhibit some form of movement, either growth-related or not, as common evidence for being alive.

Why is visible movement not enough to define life?

A plant that is not visibly growing is still alive, and some animals can breathe without visible movement.

Why are molecular movements needed for life?

Living organisms need to repair and maintain their structures, which are made up of molecules that must move around all the time.

What are life processes?

The processes that perform the maintenance job in living organisms are life processes.

What is nutrition?

Nutrition is the process to transfer a source of energy from outside the body of the organism, which we call food, to the inside.

What is respiration?

The process of acquiring oxygen from outside the body and using it in the breakdown of food sources for cellular needs.

Why is diffusion insufficient for multi-cellular organisms?

In multi-cellular organisms, all the cells may not be in direct contact with the surrounding environment, so simple diffusion will not meet the requirements of all the cells.

What is excretion?

The process by which waste by-products are removed from the body and discarded outside.

What materials do organisms use from outside?

Organisms use outside raw materials for energy, growth, development, and synthesizing necessary substances like proteins.

What is autotrophic nutrition?

When organisms use simple food material obtained from inorganic sources like carbon dioxide and water.

What organisms are autotrophs?

Green plants and some bacteria.

What is heterotrophic nutrition?

When organisms utilize complex substances that have to be broken down into simpler ones.

What organisms are heterotrophs?

Animals and fungi.

What is the role of enzymes in nutrition?

Enzymes are bio-catalysts that break down complex substances into simpler ones.

What is photosynthesis?

The process by which autotrophs take in substances from the outside and convert them into stored forms of energy using carbon dioxide, water, sunlight, and chlorophyll.

How do desert plants obtain carbon dioxide?

Desert plants take up carbon dioxide at night and prepare an intermediate which is acted upon by the energy absorbed by the chlorophyll during the day.

What are stomata?

Tiny pores present on the surface of leaves through which gaseous exchange takes place.

How do guard cells regulate the opening and closing of stomata?

Guard cells swell when water flows into them, causing the stomatal pore to open, and the pore closes if the guard cells shrink.

How do plants obtain other raw materials besides water and carbon dioxide?

Other materials like nitrogen, phosphorus, iron, and magnesium are taken up from the soil.

What forms of nitrogen do plants use?

Plants take up nitrogen in the form of inorganic nitrates or nitrites, or as organic compounds prepared by bacteria from atmospheric nitrogen.

How do some organisms break down food material?

Some organisms break-down the food material outside the body and then absorb it, while others take in whole material and break it down inside their bodies.

What is a parasitic nutritive strategy?

Deriving nutrition from plants or animals without killing them.

How does Amoeba obtain nutrition?

Amoeba takes in food using temporary finger-like extensions of the cell surface which fuse over the food particle forming a food-vacuole.

What is the alimentary canal?

A long tube extending from the mouth to the anus in human beings.

What is the role of saliva in digestion?

Saliva contains an enzyme called salivary amylase that breaks down starch into simple sugar and wets the food to make its passage smooth.

What are peristaltic movements?

Rhythmical contraction of muscles in the lining of the alimentary canal that push the food forward.

What is the role of hydrochloric acid in the stomach?

Hydrochloric acid creates an acidic medium which facilitates the action of the enzyme pepsin and protects the inner lining of the stomach from the action of the acid under normal conditions.

What is the role of bile juice from the liver?

Makes the food alkaline for the pancreatic enzymes to act and acts on fats, breaking them down into smaller globules.

What enzymes are secreted by the pancreas?

Trypsin for digesting proteins and lipase for breaking down emulsified fats.

What are villi?

Finger-like projections in the inner lining of the small intestine that increase the surface area for absorption.

What is dental plaque and how is it formed?

A mass of bacterial cells together with food particles that stick to the teeth, leading to tooth decay by producing acids.

What happens to pyruvate in anaerobic respiration?

Pyruvate is converted into ethanol and carbon dioxide in yeast during fermentation.

Where does the breakdown of pyruvate using oxygen take place?

In the mitochondria.

What happens when there is a lack of oxygen in muscle cells?

Pyruvate is converted into lactic acid, leading to muscle cramps.

What is ATP?

A molecule which is used to fuel all other activities in the cell and is the energy currency for most cellular processes.

How do plants exchange gases?

Plants exchange gases through stomata, and the large inter-cellular spaces ensure that all cells are in contact with air.

How do aquatic organisms breathe?

Aquatic organisms take in water through their mouths and force it past the gills where the dissolved oxygen is taken up by blood.

How is air filtered in the human respiratory system?

Air passing through the nostrils is filtered by fine hairs that line the passage, and the passage is also lined with mucus.

What is the role of alveoli in the lungs?

Alveoli provide a surface where the exchange of gases can take place.

What is the role of respiratory pigments?

Respiratory pigments take up oxygen from the air in the lungs and carry it to tissues which are deficient in oxygen before releasing it.

What is haemoglobin?

The respiratory pigment in human beings, present in the red blood corpuscles.

How is carbon dioxide transported in the blood?

Mostly transported in the dissolved form in our blood.

What are the components of blood?

Blood consists of a fluid medium called plasma in which the cells are suspended.

What does plasma transport?

Plasma transports food, carbon dioxide and nitrogenous wastes in dissolved form, while oxygen is carried by the red blood corpuscles.

Why does the heart have different chambers?

To prevent the oxygen-rich blood from mixing with the blood containing carbon dioxide.

What is the function of valves in the heart?

Valves ensure that blood does not flow backwards when the atria or ventricles contract.

What is double circulation?

Blood goes through the heart twice during each cycle in other vertebrates.

How is blood pressure measured?

With an instrument called sphygmomanometer.

What causes high blood pressure?

Constriction of arterioles, which results in increased resistance to blood flow.

What are arteries?

The vessels which carry blood away from the heart to various organs of the body.

What are veins?

Vessels that collect the blood from different organs and bring it back to the heart.

What are capillaries?

The smallest vessels that have walls which are one-cell thick where the exchange of material between the blood and surrounding cells takes place.

What is the role of platelets?

Platelets circulate around the body and plug leaks by helping to clot the blood at these points of injury.

What is lymph?

Another type of fluid also involved in transportation or tissue fluid

What does lymph do?

Lymph carries digested and absorbed fat from intestine and drains excess fluid from extra cellular space back into the blood.

What are xylem and phloem?

The two pathways in plants are constructed as independently organised conducting tubes. Xylem moves water and minerals, and phloem transports products of photosynthesis.

What is transpiration?

The loss of water in the form of vapour from the aerial parts of the plant.

What is translocation?

The transport of soluble products of photosynthesis from leaves to other parts of the plant in the phloem.

How is material transported in phloem?

Material like sucrose is transferred into phloem tissue using energy from ATP.

What is excretion?

The biological process involved in the removal of harmful metabolic wastes from the body.

What are the components of the human excretory system?

A pair of kidneys, a pair of ureters, a urinary bladder and a urethra.

What is the basic filtration unit in the kidneys?

Nephrons.

What is Bowman's capsule?

The cup-shaped end of a coiled tube that collects the filtrate in the kidney.

How is urine produced?

Urine is produced by filtering out waste products from the blood in the kidneys, reabsorbing useful substances, and excreting the remaining waste.

What is an artificial kidney (hemodialysis)?

A device to remove nitrogenous waste products from the blood through dialysis in case of kidney failure.

How do plants excrete?

Plants use the fact that many of their tissues consist of dead cells, and that they can even lose some parts such as leaves.