Topic 1 - Definitions And Concepts Flashcards
What is an acrosome?
An organelle in the tip of a sperm that contains enzymes which digest the egg cell membrane.
Define active site.
A specific region on an enzyme where the substrate binds and the reaction takes place.
What is active transport?
The movement of substances from a low concentration to a higher concentration (against the concentration gradient) across a membrane, with the use of energy from respiration.
What does Benedict’s test detect?
A chemical test used to test for reducing sugars that produces a different colour based on the amount of reducing sugar present.
What is the Biuret test?
A chemical test that produces a purple colour when it is added to a solution containing protein.
What does calorimetry measure?
A method of measuring heat transfer during a chemical reaction.
What are carbohydrases?
Enzymes that break down carbohydrates into simple sugars.
Fill in the blank: A carbohydrate is a large molecule that is synthesised from _______.
simple sugars.
What is a cell?
The basic building block of all living organisms.
Define cell membrane.
A partially permeable barrier that surrounds the cell.
What is the cell wall?
An outer layer made of cellulose that strengthens plant cells.
What is the function of chloroplasts?
An organelle that is the site of photosynthesis.
What is a chromosome?
A long, coiled molecule of DNA that carries genetic information in the form of genes.
What are cilia?
Hair-like structures found on ciliated epithelial cells which waft substances across the surface of the tissue in one direction.
What is a ciliated epithelial cell?
A type of epithelial cell that lines the surface of structures such as the respiratory tract and uterus.
What is a concentration gradient?
The difference in concentration between two areas.
Define denaturation.
The permanent change in the shape of an enzyme’s active site that prevents the binding of a substrate upon exposure to high temperatures or extremes of pH.
What is diffusion?
The net spreading out of particles from a high concentration to a lower concentration (down their concentration gradient).
What is a diploid cell?
A cell that contains two copies of each chromosome (i.e. a full set of chromosomes).
What is an egg cell?
A specialised female sex cell involved in reproduction.
What type of microscope uses a beam of electrons to produce an image?
Electron microscope.
What is the emulsion test?
A chemical test that produces a cloudy emulsion when performed on lipids.
Define enzyme.
A biological catalyst that increases the rate of reactions in living organisms.
What is a eukaryotic cell?
A type of cell found in plants and animals that contains a nucleus.
What are flagella?
A long hair-like structure found on bacterial cells that is used for cell movement.
What is a haploid cell?
A cell that contains a single copy of each chromosome (i.e. half the number of chromosomes).
What does the iodine test indicate?
Produces a blue/black colour when iodine solution is added to a sample containing starch.
What is a light microscope?
A type of microscope that uses a series of lenses to magnify the visible light reflecting off a specimen.
What do lipases do?
Enzymes that break down lipids into fatty acids and glycerol.
Define lipid.
A large molecule that is synthesised from fatty acids and glycerol.
What is the lock and key hypothesis?
A theory that describes how substrates must be the correct shape to fit the active site of an enzyme.
What is magnification?
The number of times bigger an image appears compared to the original object.
Fill in the blank: One micrometre (um) is equal to _______ metre.
x 10^(-6) metre.
Fill in the blank: One millimetre (mm) is equal to _______ metre.
x 10^(-3) metre.
What is mitochondria?
An organelle that is the site of respiration
Mitochondria are often referred to as the powerhouse of the cell.
Define nanometre (nm).
A quantitative unit of length. One nanometre is equal to ×10^-9 metre
Used in measuring things at the molecular or atomic level.
What is the function of the nucleus?
Contains the genetic material of the cell and controls the activities of the cell
Found in most eukaryotic cells.
What is an organelle?
A specialised structure found inside a cell
Organelles perform specific functions necessary for the cell’s life.
Define osmosis.
The diffusion of water molecules from a region of high water concentration to a region of lower water concentration across a partially permeable membrane
Crucial for maintaining cell turgor and overall homeostasis.
How is percentage change in mass calculated?
Percentage change in mass = (final mass - initial mass) / initial mass × 100
Used to quantify changes in mass over time.
What is a picometre (pm)?
A quantitative unit of length. One picometre is equal to ×10^-12 metre
Often used in fields like nuclear physics and chemistry.
What is a plasmid?
Loops of DNA found in the cytoplasm of prokaryotic cells
Plasmids can carry genes that provide advantages, such as antibiotic resistance.
Define prokaryotic cell.
A type of cell found in bacteria that does not contain a nucleus
Prokaryotic cells are generally simpler and smaller than eukaryotic cells.
What are proteases?
Enzymes that break down proteins into amino acids
Important for digestion and cellular processes.
What is a protein?
A large molecule that is synthesised from amino acids
Proteins perform a vast array of functions within organisms.
What does rate of reaction refer to?
The speed at which reactants are converted into products
Influenced by factors such as temperature and concentration.
Define resolution in a biological context.
The smallest distance between two objects that can be distinguished
Important in microscopy and imaging techniques.
What are ribosomes?
Sub-cellular structures that are the site of protein synthesis
Can be found free in the cytoplasm or attached to the endoplasmic reticulum.
What is a specialised cell?
A cell that has a structure which makes it adapted to its function
Examples include nerve cells and muscle cells.
Define specificity in relation to enzymes.
Describes the ability of an enzyme to catalyse only a particular reaction or set of reactions
This occurs because the substrate fits the active site of the enzyme.
What is a sperm cell?
A specialised male sex cell that is involved in reproduction
Sperm cells are designed for motility and delivering genetic material.
What is the function of a vacuole?
An organelle found in plant cells which stores cell sap and supports the cell
Vacuoles help maintain turgor pressure in plant cells.
