Grade 11 Life Sciences: Photosynthesis, Nutrition, Cellular Respiration, and Gaseous Exchange

Comprehensive vocabulary flashcards covering Grade 11 Life Sciences topics: Photosynthesis and Greenhouse Cultivation, Human Nutrition and Digestion, Cellular Respiration and Fermentation, and Gaseous Exchange across various organisms.

Photosynthesis

The building up of carbohydrates (glucose) from carbon dioxide and water using radiant energy from the sun trapped by chlorophyll, releasing oxygen as a product.

Photolysis

The chemical process during the light phase where radiant energy is transformed into chemical energy to split water molecules into energy-rich hydrogen atoms and oxygen gas.

Chloroplast

The plant cell organelle where photosynthesis occurs, consisting of a double membrane, stroma, and grana (lamellae or thylakoids).

Light phase

The light-dependent phase of photosynthesis taking place in the grana (lamellae) of chloroplasts, during which photolysis occurs and the energy carrier ATP is formed.

Dark phase (Calvin cycle)

The light-independent phase of photosynthesis occurring in the stroma of chloroplasts, where carbon dioxide combines with energy-rich hydrogen atoms using energy from ATP to produce glucose.

Greenhouse

A structure with a glass roof and walls designed to cultivate plants by trapping warm air and maintaining optimal conditions of light, temperature, and $CO_2$ for maximum plant growth.

Optimum temperature for photosynthesis

$25^\circ\text{C}$, the temperature at which plant enzymes photosynthesise most effectively before low temperatures inactivate enzymes or higher temperatures denature them and close stomata.

$CO_2$ enrichment

The agricultural practice of increasing carbon dioxide levels in a greenhouse by pumping $CO_2$ gas from tanks or adding sodium bicarbonate and organic materials to the soil.

Carnivore dentition

Dental adaptations characterized by sharp-ended incisors to bite off food, long and strong canines to pierce and tear prey apart, and premolars and molars with sharp protrusions to cut food.

Human dental formula

The numeric representation of the human dentition per half jaw: $\frac{2.\,1.\,2.\,3}{2.\,1.\,2.\,3}$, representing 2 incisors, 1 canine, 2 premolars, and 3 molars.

Alimentary canal

A continuous tubular organ system extending throughout the body consisting of the mouth cavity, pharynx, oesophagus, stomach, small intestine, large intestine, and anus.

Epiglottis

A thin, leaf-shaped cartilage structure located at the top of the larynx that closes the glottis during swallowing to prevent food from entering the trachea.

Peristalsis

The involuntary contraction of circular muscles above a food bolus and circular muscle relaxation below it that pushes food downward through the digestive tract.

Chemical digestion

The breakdown of large, insoluble food molecules into smaller, soluble molecules by the addition of water (hydrolysis) with the catalytic help of enzymes.

Villus

A microscopic, finger-like projection in the small intestine wall containing a capillary network and lacteal, structured to significantly maximize nutrient absorption.

Deamination

The physiological process occurring in the liver whereby excess amino acids are broken down to form urea and glucose.

Gall bladder

A muscular sac situated between liver lobes that stores bile produced by the liver and releases it into the duodenum via the common bile duct.

Homeostasis

The tendency of living organisms to maintain a constant internal environment (body fluid bathing the cells) within narrow limits despite external variations.

Insulin

A hormone secreted by the beta ($\beta$) cells of the islets of Langerhans that decreases elevated blood sugar by promoting glucose absorption by cells and glycogen synthesis in the liver and muscles.

Glucagon

A hormone produced by the alpha ($\alpha$) cells of the islets of Langerhans that elevates low blood sugar by stimulating the breakdown of liver glycogen into glucose.

Diabetes mellitus

A chronic metabolic disease marked by abnormally high glucose levels in the blood resulting from insufficient insulin production, lack of secretion, or impaired cellular response to insulin.

Kwashiorkor

A form of malnutrition seen predominantly in growing children caused specifically by a dietary deficiency of protein.

Marasmus

A deficiency condition occurring in infants older than six months breastfed without supplemental food, resulting from an overall lack of energy-yielding nutrients (carbohydrates and fats).

Cellular respiration

The catabolic process of breaking down organic compounds (glucose) to gradually release energy stored in ATP, consuming oxygen and producing carbon dioxide and water as waste.

Mitochondrion

The double-membraned organelle containing cristae and a matrix that hosts the aerobic stages of cellular respiration (Kreb's cycle and oxidative phosphorylation).

Glycolysis

The initial anaerobic stage of cellular respiration occurring in the cytosol, where a 6-carbon glucose molecule is broken down into two 3-carbon pyruvic acid molecules, yielding ATP and energy-rich H-atoms.

Kreb's cycle

The aerobic cyclic pathway occurring inside the mitochondrial matrix where pyruvic acid is systematically broken down to release $CO_2$ and energy-rich hydrogen atoms carried by coenzymes.

Oxidative phosphorylation

The aerobic stage taking place on the mitochondrial cristae where energy released by transferring hydrogen atoms across acceptors binds phosphate to ADP to synthesize ATP, with oxygen serving as the final hydrogen acceptor.

Lactic acid fermentation

Anaerobic respiration occurring in muscle cells during vigorous exercise where pyruvic acid is converted into lactic acid, producing a small quantity of energy.

Oxygen debt

The volume of oxygen required following intense physical activity to metabolize and convert accumulated lactic acid back into pyruvic acid.

Alcoholic fermentation

Anaerobic respiration in plant cells and yeast where pyruvic acid is broken down into alcohol (ethanol) and carbon dioxide with low energy release.

Breathing

The mechanical process whereby air moves into and out of the lungs through changes in thoracic pressure.

Gaseous exchange

The physical process involving the diffusion of oxygen and carbon dioxide across a moist, thin, and large gaseous exchange surface.

Diffusion

The passive net movement of molecules from a region of higher concentration to a region of lower concentration until dynamic equilibrium is reached.

Spiracles

External openings on the thorax and abdomen of insects (such as locusts) that admit and expel air into an internal branched tracheal system.

Turbinate bones

Three curved bones situated inside each nasal cavity that divide the cavity into three distinct passages to warm, moisten, and filter incoming air.

C-shaped cartilage rings

Incomplete cartilage rings supporting the tracheal wall that keep the windpipe open while allowing the adjacent oesophagus to expand during swallowing.

Pleura

A double membrane enclosing each lung, containing intrapleural fluid to eliminate friction during respiratory expansion and shrinkage.

Inhalation

An active ventilatory phase wherein the diaphragm flattens and external intercostal muscles lift ribs upward and outward, increasing thoracic volume and decreasing internal pressure.

Exhalation

A normally passive ventilatory phase wherein the diaphragm and external intercostal muscles relax, decreasing thoracic volume and elevating internal pressure above atmospheric pressure to expel air.

Alveoli

Microscopic thin-walled air sacs grouped into infundibula in mammalian lungs that provide a large, moist surface of single-layered squamous epithelium for respiratory gas exchange.

Capillary endothelium

The single layer of squamous epithelial cells composing capillary walls across which oxygen and carbon dioxide diffuse between blood and tissues or alveoli.