Combined Science Revision Study Notes Flashcards

Vocabulary flashcards covering fundamental topics in Combined Science including life processes, cell biology, biological molecules, enzymes, plant and animal nutrition/transport, immunity, respiration, reproduction, and ecology.

Movement

A change in place or position.

Respiration

Chemical reaction involving the break down of food, mainly glucose, to release energy.

Sensitivity

Ability to detect a stimulus (change in the environment) and carry out a response.

Growth

Permanent increase in number and size of cells as well as dry mass.

Reproduction

Making more of the same kind of organism.

Nutrition

The ability to make or obtain nutrients to provide energy for growth and development.

Excretion

Removal of toxic metabolic waste products or substances found in excess out of the body.

Nucleus

Cell organelle that controls cell activities, contains DNA, and controls cell division.

Cytoplasm

Cellular fluid that acts as the site of chemical reactions.

Cell membrane

Structure made from proteins and fats that keeps cell contents inside and controls the movement of substances in and out of the cell.

Mitochondrion

Organelle that serves as the site of aerobic respiration to release energy.

Endoplasmic reticulum

Organelle where ribosomes are attached for protein synthesis.

Chloroplast

Organelle containing chlorophyll to trap light energy for photosynthesis, converting light energy into chemical energy stored in glucose.

Cell wall

Structure made from cellulose with high tensile strength that gives support and strength, prevents the cell from bursting, and keeps the cell turgid.

Vacuole

Organelle containing water, salts, and sugars that presses outwards on the cell wall to keep the cell turgid.

Red blood cell

Specialised cell adapted with a biconcave flat shape for a larger surface area, no cell organelles to provide more space for haemoglobin, and flexibility to squeeze through capillaries to transport oxygen.

Ciliated epithelium

Tissue containing goblet cells that secrete sticky mucus to trap dust and bacteria, and cilia that beat to sweep mucus out of the lungs back to the throat.

Sperm cell

Male gamete cell featuring a flagellum for swimming, a middle part full of mitochondria for movement energy, and a head containing a haploid nucleus and an acrosome with digestive enzymes.

Egg cell

Female gamete containing a haploid nucleus, dense cytoplasm with a large food storage acting as energy storage, and a protective jelly coat that hardens after fertilisation.

Root hair cell

Specialised plant cell with a cytoplasmic extension for larger surface area, a concentrated vacuole for water uptake by osmosis, thin cell wall, and many mitochondria for active mineral transport.

Diffusion

Movement of substances from an area of high concentration to an area of low concentration due to random movement of molecules.

Osmosis

Movement of water molecules from an area of higher water potential to an area of lower water potential through a partially permeable membrane.

Active transport

Movement of particles or molecules through a cell membrane from an area of low concentration to an area of high concentration against the gradient, using energy from respiration.

Macromolecules

Large molecules with large molecular mass.

Carbohydrates

Biological molecules composed of $\text{C}, \text{H}, \text{O}$ made up of simple sugars like glucose, serving as a primary source of energy from respiration.

Proteins

Biological molecules composed of $\text{C}, \text{H}, \text{O}, \text{N}$ made of amino acids, required for growth, tissue repair, and formation of enzymes, antibodies, and hormones like insulin.

Fats / Lipids

Biological molecules composed of $\text{C}, \text{H}, \text{O}$ made of $3$ fatty acids and $1$ glycerol, functioning as stored energy, thermal/electrical insulation, and organ protection.

Iodine solution test

Food test used to detect the presence of starch.

Benedict's test

Food test used to detect reducing sugars.

Biuret test

Food test used to detect the presence of proteins.

Ethanol emulsion test

Food test used to detect fats and lipids.

Deamination

Process occurring in the liver where excess amino acids are broken down to produce urea.

Vitamin C

Vitamin essential to strengthen blood vessels; deficiency causes scurvy (bleeding gums) and poor wound healing.

Vitamin D

Vitamin obtained from the sun that aids calcium absorption into bones to strengthen bones and teeth; deficiency causes fragile bones and rickets in children.

Iron

Mineral required to make haemoglobin; deficiency causes anaemia, pale skin, lack of energy, and shortness of breath.

Calcium

Mineral required to build strong bones and teeth; deficiency causes fragile bones and rickets in children.

Dietary fibre

Food component that stimulates peristalsis down the alimentary canal to prevent constipation and colon cancer.

Balanced diet

Daily intake of all nutrients in the correct amount to provide the body with needed energy for growth and development according to age, gender, and physical activity.

Malnutrition

Condition caused by eating too much or too little of a specific nutrient.

Starvation

Condition of not eating enough food over a long time where the body sequentially breaks down carbohydrates, then fats, and then proteins, leading to shrunken muscles.

Enzymes

Protein molecules that act as biological catalysts to speed up chemical reactions without themselves being changed.

Active site

Region on an enzyme with a specific shape that is complementary to a substrate molecule, forming an enzyme-substrate complex.

Optimum temperature

Temperature at which an enzyme shows maximum activity and forms the maximum number of enzyme-substrate complexes.

Denaturation

Loss of an enzyme's active site 3D shape at temperatures above optimum or extreme pH, preventing substrate binding and enzyme-substrate complex formation.

Photosynthesis

Process by which plants make glucose from carbon dioxide and water using light energy trapped by chlorophyll ($6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$).

Palisade mesophyll

Leaf tissue layer packed with chloroplasts for maximum light energy absorption during photosynthesis.

Spongy mesophyll

Leaf tissue layer loosely packed with large air spaces to facilitate gas exchange and diffusion of gases.

Guard cells

Specialised plant cells that control the opening and closing of stomata.

Destarching

Procedure of placing a plant in the dark for $48\text{ hours}$ to ensure all stored starch is used up by respiration before testing factors needed for photosynthesis.

Ingestion

Taking in of food into the body through the mouth.

Absorption

Movement of small food molecules from the walls of the small intestine into the blood.

Egestion

Removal of undigested food out of the body in the form of faeces through the anus.

Mechanical digestion

Physical breakdown of large food pieces into smaller ones with no chemical change to increase surface area for enzyme action.

Chemical digestion

Breakdown of large insoluble food molecules into smaller soluble ones by enzymes to allow absorption into the blood.

Bile juice

Fluid produced by the liver and stored in the gallbladder that carries out emulsification of fats to facilitate chemical digestion.

Xylem vessels

Vascular plant tissue with lignified walls containing pits, responsible for transporting water and mineral ions upwards and supporting the plant.

Phloem

Vascular plant tissue responsible for transporting sucrose and amino acids from source to sink.

Transpiration

Evaporation of water surrounding mesophyll cells followed by the diffusion of water vapour out of leaves through stomata.

Potometer

Apparatus used to measure the rate of water loss or water uptake in a cut plant shoot.

Double circulatory system

Circulatory system where blood passes through the heart twice in one complete circuit, separating oxygenated and deoxygenated blood and maintaining two different pressures.

Coronary arteries

Blood vessels supplying oxygen and glucose directly to the heart muscle for aerobic respiration.

Coronary Heart Disease (CHD)

Disease caused by atheroma/fat buildup in coronary artery walls, narrowing vessels and reducing oxygen and glucose delivery to heart muscle.

Plasma

Liquid fraction of blood ($55\%$) composed of $90\%$ water and $10\%$ dissolved substances (glucose, urea, $\text{CO}_2$) and proteins (antibodies, enzymes, hormones).

Arteries

Blood vessels with thick collagen walls, elastic fibres, and narrow lumens that carry oxygenated blood away from the heart under high pressure.

Capillaries

Microscopic blood vessels with walls one cell thick containing pores to facilitate substance exchange between blood and body cells.

Veins

Blood vessels with thin walls, wide lumens, and semilunar valves that carry deoxygenated blood back to the heart under low pressure.

Pathogen

Disease-causing microorganism living inside a host, such as viruses, bacteria, or fungi.

Infectious disease

Disease caused by a pathogen that can be transmitted from one host living organism to another.

Lymphocytes

White blood cells that detect foreign pathogens, divide to produce clones, and secrete specific antibodies while producing memory cells.

Vaccine

Preparation of weak or dead pathogens injected to stimulate an active immune response and generate memory cells.

Antibiotics

Chemical substances produced by microorganisms (mainly fungi) that kill bacteria or stop their growth by damaging cell walls.

Aerobic respiration

Chemical reaction breakdown of glucose in the presence of oxygen to release energy ($\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O}$).

Anaerobic respiration

Chemical breakdown of glucose in the absence of oxygen to release energy, producing lactic acid in muscles ($\text{C}_6\text{H}_{12}\text{O}_6 \rightarrow 2\text{C}_3\text{H}_6\text{O}_3$).

Alveoli

Structures in lungs adapted for rapid gas exchange with large surface area, thin one-cell-thick walls, and dense surrounding capillary networks.

Ovulation

Release of a mature egg from a follicle in the ovary into the oviduct around the middle of the menstrual cycle.

Fertilisation

Fusion of male and female haploid nuclei to form a diploid zygote.

Pollination

Transfer of pollen grains from an anther to a stigma.

Ecosystem

A self-sustained unit formed by the interaction between a community of living organisms and their environment.

Population

Group of individuals of the same species living in the same place at the same time.

Community

All populations of different living organisms interacting in the same place at the same time.

Trophic level

Position occupied by an organism in a food chain or food web.

Eutrophication

Process where excess fertilisers or untreated sewage lead to an explosion in bacterial population, depleting oxygen levels in water and causing death or migration of aquatic life.

Endangered species

Species with a very low population size, making them at risk of extinction.