Topic 1 - Key Concepts Of Biology - Definitons And Concepts Flashcards
What is an acrosome?
An organelle in the tip of a sperm that contains enzymes which digest the egg cell membrane.
What is the active site of an enzyme?
A specific region on an enzyme where the substrate binds and the reaction takes place.
Define 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 is Benedict’s test used for?
A chemical test used to test for reducing sugars that produces a different colour based on the amount of reducing sugar present.
What does a positive Biuret test indicate?
A purple colour when it is added to a solution containing protein.
What is calorimetry?
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 synthesized 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 function of the cell wall?
An outer layer made of cellulose that strengthens plant cells.
What is a chloroplast?
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 in the context of enzymes.
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 used for?
A chemical test that produces a cloudy emulsion when performed on lipids.
Define an 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?
It 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 are lipases?
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 is equal to _______.
× 10^-6 metre.
Fill in the blank: One millimetre is equal to _______.
× 10^-3 metre.
What is an organelle that is the site of respiration?
Mitochondria
Mitochondria are often referred to as the powerhouse of the cell.
What is a quantitative unit of length equal to 10^-9 metre?
Nanometre (nm)
Nanometres are commonly used to measure wavelengths of light and dimensions of atoms.
What organelle contains the genetic material of the cell?
Nucleus
The nucleus controls the activities of the cell and is found in most eukaryotic cells.
What is a specialised structure found inside a cell called?
Organelle
Organelles perform specific functions vital 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
Osmosis is crucial for maintaining cellular homeostasis.
How is percentage change in mass calculated?
percentage change in mass = (final mass - initial mass) / initial mass × 100
This formula is used to determine the change in mass over a set period.
What is a quantitative unit of length equal to 10^-12 metre?
Picometre (pm)
Picometres are often used in atomic and molecular measurements.
What are loops of DNA found in the cytoplasm of prokaryotic cells called?
Plasmid
Plasmids can carry genes that provide bacteria with genetic advantages.
What type of cell is found in bacteria and does not contain a nucleus?
Prokaryotic cell
Prokaryotic cells are simpler and smaller than eukaryotic cells.
What are enzymes that break down proteins into amino acids called?
Proteases
Proteases play key roles in digestion and protein metabolism.
What is a large molecule that is synthesised from amino acids?
Protein
Proteins serve various functions, including structural, enzymatic, and regulatory roles.
What is the speed at which reactants are converted into products known as?
Rate of reaction
The rate of reaction can be affected by factors like temperature and concentration.
Define resolution in a scientific context.
The smallest distance between two objects that can be distinguished
Resolution is crucial in microscopy and imaging.
What are the sub-cellular structures that are the site of protein synthesis?
Ribosomes
Ribosomes can be found free in the cytoplasm or attached to the endoplasmic reticulum.
What is a cell that has a structure adapted to its function called?
Specialised cell
Examples include nerve cells, muscle cells, and blood cells.
What describes the ability of an enzyme to catalyse only a particular reaction or set of reactions?
Specificity
Specificity ensures that enzymes only interact with specific substrates.
What is a specialised male sex cell involved in reproduction?
Sperm cell
Sperm cells are designed for motility and fertilization.
What organelle found in plant cells stores cell sap and supports the cell?
Vacuole
Vacuoles play a crucial role in maintaining turgor pressure in plant cells.
