Year 11 Biology - Cells, Organisms, Digestion, and Transport Systems

Flashcards covering key terminology across plant biochemical processes, digestive structures, circulatory structures, multicellularity, and cellular blood components.

Chlorophyll

A green substance located in chloroplasts, mostly within the mesophyll layer, that absorbs red and blue wavelengths of light to drive photosynthesis while reflecting green light.

Light Dependent Reaction

The first stage of photosynthesis occurring in the thylakoid stacks of the grana, which uses sunlight and water to produce oxygen, ATP, and NADPH.

Light Independent Reaction

Also known as the Calvin Cycle, this stage occurs in the stroma and uses ATP and NADPH from the light dependent reaction to fix carbon dioxide into glucose.

Thylakoids

Structures in the grana of chloroplasts where the light dependent reactions of photosynthesis take place.

Stroma

The fluid-filled space within chloroplasts where the light independent reaction (Calvin Cycle) takes place.

Aerobic Respiration

A chemical process in living organisms that requires oxygen to break down organic compounds to release energy.

Anaerobic Respiration

A chemical process in living organisms that breaks down organic compounds to release energy without requiring oxygen.

Rugae

Ridges of muscle tissue lining the stomach that contract periodically to churn food during physical digestion.

Duodenum

The first segment of the small intestine primarily responsible for the continuous chemical breakdown of food using pancreatic enzymes and liver bile.

Jejunum and Ileum

The middle and final segments of the small intestine, lined with villi to create a large surface area for absorbing nutrients into the bloodstream.

Gallbladder

An organ that stores and concentrates bile produced by the liver, releasing it into the duodenum to assist in digesting and absorbing fats.

Pancreatic Alpha Cells

Specialised cells in the pancreas that produce the hormone glucagon to regulate blood glucose levels.

Pancreatic Beta Cells

Specialised cells in the pancreas that produce the hormone insulin to regulate blood glucose levels.

Peristalsis

Wavelike muscular contractions that move stool or waste material through the colon.

Arteries

Blood vessels with thick, elastic walls made of endothelium, smooth muscle, and connective tissue that carry blood away from the heart under high pressure.

Capillaries

Microscopic blood vessels only one cell thick that surround tissues, providing a large surface area and reduced blood velocity for efficient gas and nutrient exchange.

Veins

Blood vessels with thin walls, wider diameters, and internal valves that carry blood back towards the heart under low pressure.

Open Circulatory System

A transport system where circulating fluid (hemolymph) is pumped into open body cavities (hemocoels) to directly bathe organs under low pressure.

Closed Circulatory System

A transport system where blood remains entirely confined within blood vessels and is pumped at high pressure by a heart.

Hemolymph

The fluid in an open circulatory system where there is no distinction between blood and interstitial fluid.

Unicellular Organism

An organism composed of a single cell that carries out all required life functions without cell specialisation.

Colonial Organism

An organism composed of individual single cells living together where every cell can perform all life functions independently.

Multicellular Organism

An organism composed of many cells working together, characterized by cell specialisation and high tissue organization.

Erythrocytes

Red blood cells; bi-concave, non-nucleated cells produced in bone marrow that contain haemoglobin and transport respiratory gases.

Leukocytes

White blood cells; nucleated, irregular-shaped blood cells produced in bone marrow that defend the body against disease.

Thrombocytes

Platelets; tiny non-nucleated cell fragments produced in bone marrow that function in blood clotting.

Plasma

The straw-coloured liquid portion of blood making up $55\times 10^{-2}$ ($550\text{ g/kg}$ or $55$%) of blood volume, composed of $90$% water, which transports cells, nutrients, hormones, and wastes.