IGCSE Biology Comprehensive Review

Practice vocabulary flashcards based on an IGCSE Biology review transcript.

Normal light microscope

A tool that allows us to see cells and maybe the nucleus, but not finer subcellular structures.

Electron microscope

A tool used to see far finer details and organels due to its better resolving power and higher resolution.

Organels

Subcellular structures visible in finer detail through an electron microscope.

Magnification formula

$$\text{Magnification} = \frac{\text{image size}}{\text{object size}}$$

Actual size calculation

Calculating the real size of a cell using the image size and the magnification of the microscope.

Ukarotic cells

Main group of cells that have a nucleus in which their DNA is found, such as plant and animal cells.

Proarotic cells

Main group of cells that do not have a nucleus.

Cell membrane

A structure that keeps everything inside the cell and is semi, partially, or selectively permeable.

Selectively permeable

A membrane property that allows certain substances to pass through while blocking others.

Cell wall (Plant)

An extra layer made of cellulose that providing a rigid structure for the cell.

Cellulose

The material that makes up the cell wall in plant cells.

Cell wall (Bacteria)

A structure present in bacteria that is not made of cellulose.

Cytoplasm

The liquid making up the cell in which most chemical reactions take place.

Mitochondria

The site of respiration where energy is released for cellular function.

Ribosomes

The site of protein synthesis where amino acids are assembled into proteins.

Protein synthesis

The process of assembling amino acids into proteins at the ribosomes.

Chloroplasts

The site of photosynthesis in plant cells containing chlorophyll.

Chlorophyll

A green substance found in chloroplasts used for photosynthesis.

Permanent vacule

A structure in plant cells where sap is stored.

Sap

The liquid stored within the permanent vacule of a plant cell.

Diffusion

The movement of molecules or particles from an area of high concentration to an area of low concentration.

Concentration gradient

The difference in concentration across which particles move 'down' like a ball rolling down a hill.

Passive transport

Movement that does not require any energy input, such as diffusion.

Osmosis

The name specifically given to the movement of water across a semi-permeable membrane.

Rate increasing factors (Diffusion/Osmosis)

Increasing the difference in concentrations, increasing temperature, or increasing the surface area of the membrane.

Villi cells

Lumpy cells in the small intestine that provide a very high surface area to volume ratio.

Alvioli

The air sacks in the lungs that provide a high surface area to volume ratio for gas exchange.

Root hair cells

Plant cells with a high surface area to volume ratio for efficient transport.

Osmosis practical

Cutting equal-sized cylinders of a vegetable, weighing them, and placing them in varying sugar solutions.

Percentage change in mass formula

$$\frac{\text{final mass} - \text{initial mass}}{\text{initial mass}} \times 100$$

Negative change in mass

Result when a vegetable cylinder is lighter after the osmosis practical than it was before.

Line of best fit (Osmosis)

A line drawn on a graph of percentage mass change against sugar concentration.

X-axis crossing point (Osmosis)

The concentration where no change in mass occurred, indicating the concentration inside the potato itself.

Active transport

Movement of nutrients through a membrane against a concentration gradient using energy.

Carrier proteins

Proteins in the membrane that use energy to move substances through the membrane during active transport.

Mineral ions (Active transport)

Substances moved into plant root hair cells against the concentration gradient.

Tissue

A group of similar cells connected together, like heart tissue.

Organs

Structures formed from tissues, such as the heart.

Organ system

A group of organs working together, like the circulatory system.

Digestive system

The system that breaks down food into useful nutrients for the body.

Stomach acid

Acid used to break down food in the stomach.

Bile

A substance made in the liver and stored in the gallbladder used to neutralize stomach acid and emulsify fats.

Liver

The organ where bile is produced.

Gallbladder

The organ where bile is stored before being used.

Fat emulsification

The process of bile forming droplets to increase the surface area of fats for enzymes.

Teeth (Physical digestion)

The physical breakdown of food into smaller bits to increase surface area for chemical digestion.

Chemical digestion

The process of enzymes changing food into something else, beginning in the stomach.

Incisors

One of four main types of teeth.

Canines

Teeth used for ripping food apart.

Preolars and mers

Types of teeth used for chewing.

Enzymes

Biological catalysts that break down larger molecules into smaller ones to be absorbed into the bloodstream.

Amalayise

The enzyme that breaks down starch into moltos and eventually glucose.

Moltos

A sugar produced when amalayise breaks down starch.

Specific (Enzymes)

The property of enzymes only breaking down certain molecules due to the lock and key principle.

Carbohydrases

Enzymes that break down carbohydrates into simple sugars.

Proteases

Enzymes that break down proteins into amino acids.

Lipases

Enzymes that break down lipids (fats) into glycerol and fatty acids.

Substrate

The molecule (e.g., starch) that binds to the enzyme's active site.

Active site

The specific area on an enzyme where the substrate binds.

Complex

The structure formed when a substrate is bound to an enzyme's active site.

Lock and key principle

The idea that enzymes only work if the substrate is the right shape to fit the active site.

Denatured

When an enzyme's active site changes shape, preventing the substrate from binding.

Optimum temperature

The temperature at which the maximum rate of enzyme activity occurs.

Optimum pH

The pH level where the enzyme activity is at its highest rate.

Enzyme practical reagents

Amalayise, starch, iodine solution, and pH buffer solutions.

Spotting tile dimple

The location where drops of starch mixture and iodine are combined during an enzyme practical.

Iodine solution color (Starch present)

Black.

Iodine solution color (Starch broken down)

Orange.

Optimum pH (Biology convention)

Strictly defined as being situated between the two lowest points on a time-taken graph.

Benedict solution

A semi-quantitative test for sugars that turns from blue to brick red.

Biruets reagent

A chemical that turns from blue to purple in the presence of proteins.

Cold ethanol test

A test for lipids (fats) that produces a cloudy result if they are present.

Starch sources

Bread, cereal, pasta, and potatoes.

Protein sources

Meat, eggs, and nuts.

Vitamin C

Nutrient needed to keep you healthy; deficiency causes scurvy.

Scurvy symptoms

Destruction of gums and hair.

Vitamin D

Nutrient for bones and muscles; deficiency causes ricketetts.

Ricketetts symptoms

Bowing of the legs.

Calcium

Mineral needed for healthy bones; deficiency causes osteoporosis.

Osteoporosis

A condition resulting from a lack of calcium.

Iron

Mineral needed for red blood cells; deficiency causes anemia.

Fiber

Also called roughage, it keeps the digestive system working properly.

Double circulatory system

A system where blood enters the heart twice for every full pump around the body.

Vennea

The main vein through which deoxygenated blood from the body enters the right atrium.

Right atrium

The chamber where deoxygenated blood enters the heart.

Heart valves

Structures like the one between the atrium and ventricle that stop the back flow of blood.

Pulmonary artery

The blood vessel carrying deoxygenated blood to the lungs to be oxygenated.

Pulmonary vein

The blood vessel carrying oxygenated blood back from the lungs to the left atrium.

Left ventricle

The chamber which pumps oxygenated blood to the whole body, possessing thicker walls.

Aorta

The main artery through which blood leaves the left ventricle to the whole body.

Artificial pacemaker

A device used if the cells in the right atrium cannot properly create electrical pulses for heartbeats.

Arteries

Blood vessels that carry blood away from the heart, typically high-pressure and thicker-walled.

Veins

Blood vessels that carry blood towards the heart, possessing thinner walls and valves.

Lumen

The hole in the middle of a blood vessel that blood travels through.

Capillaries

Tiny blood vessels with one cell thick walls to allow fast diffusion of molecules.

Coronary artery

The artery that delivers a supply of oxygen and blood specifically to the heart muscle.

CHD

Coronary heart disease, caused by the buildup of fatty deposits in the coronary artery.

Stancents

Little tubes inserted into blood vessels to keep them open for blood flow.

Statins

Drugs used to reduce cholesterol and fatty deposits in blood vessels.

Faulty heart valves

Valves resulting in backflow that can be replaced with artificial ones.