Biology- Life processes

Characteristics of living things

Movement, growth, sensitive, respire, excrete, reproduce, and utilize nutrients

Life processes

Basic functions performed by living organisms for maintaining life

Nutrition

Process of intake and utilisation of nutrients in food by an organism, as an energy resource or for the biosynthesis of body constituents.

Autotrophic Nutrition

Type of nutrition in which organisms synthesise organic material from inorganic material- plants and blue green algae.

Steps of photosynthesis

1. Absorption of light by chlorophyll

2. Conversion of light energy to chemical energy and splitting of water into o2 and h2.

3. Reduction of co2 to produce carbohydrates.

Chloroplast- function, chlorophyll and location

Site of photosynthesis. Below upper epidermis in a tissue called palisade. chlorophyll absorb light

Where does gaseous exchange occur?

in leaves through stomata and also on the surface of stems, roots and leaves.

When does stomata open and close?

When guard cells swell when water flows through them causing stomata to open and when they shrink stomata closes

Heterotrophic nutrition

Type of nutrition in which energy is derived from the intake and digestion of the organic substances obtained from a plant or animal.

Saprophytic Nutrition

Obtain nutrients from dead and decaying organic matter- fungi and bacteria

Parasitic nutrition

Organism (parasite) obtains food synthesised by other (host)- Cuscuta, Plasmodium and lice.

Holozoic nutrition

Complex organic matter is taken in by ingestion and is digested and absorbed- amoeba and humans.

Phagocytosis

A process by which living organisms engulf large particles mainly food using its plasma membrane.

Assimilation and Egestion (Amoeba)

Digested food diffuses into the cytoplasm and utilized by the cell. The undigested food in the food vacuole is thrown out of the body.

Name the 5 steps of nutrition in amoeba.

Ingestion → Digestion → Absorption → Assimilation → Egestion

Name the glands associated with human digestion.

Salivary glands, liver and pancreas

Peristaltic movement

The rhythmic contraction and relaxation in the alimentary canal

Salivary amylase

Secreted by salivary glands and converts starch into sugar

Gastric Juices

Secreted by the glands in the walls of stomach. Contains pepsin, HCL, and mucus.

Pepsin

Secreted by stomach and acts on protein in an acidic medium

Function of HCL in stomach

1. to create an acidic medium for pepsin to act

2. Kill any bacteria that enters with the food.

Muscle that is present in the stomach that release small amount of food in in small intestine

Sphincter muscle

Largest part of alimentary canal

Small intestine- 6.5 m long

How does the length on small intestine differ in different animals? Give examples of carnivores and herbivores.

It depends on the food to be digested. in herbivores, it is long as