Topic 1 - Key Concepts Of Biology - Definitons And Concepts

Question 1

What is an acrosome?

Answer 1

An organelle in the tip of a sperm that contains enzymes which digest the egg cell membrane.

Question 2

What is the active site of an enzyme?

Answer 2

A specific region on an enzyme where the substrate binds and the reaction takes place.

Question 3

Define active transport.

Answer 3

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.

Question 4

What is Benedict’s test used for?

Answer 4

A chemical test used to test for reducing sugars that produces a different colour based on the amount of reducing sugar present.

Question 5

What does a positive Biuret test indicate?

Answer 5

A purple colour when it is added to a solution containing protein.

Question 6

What is calorimetry?

Answer 6

A method of measuring heat transfer during a chemical reaction.

Question 7

What are carbohydrases?

Answer 7

Enzymes that break down carbohydrates into simple sugars.

Question 8

Fill in the blank: A carbohydrate is a large molecule that is synthesized from _______.

Answer 8

simple sugars.

Question 9

What is a cell?

Answer 9

The basic building block of all living organisms.

Question 10

Define cell membrane.

Answer 10

A partially permeable barrier that surrounds the cell.

Question 11

What is the function of the cell wall?

Answer 11

An outer layer made of cellulose that strengthens plant cells.

Question 12

What is a chloroplast?

Answer 12

An organelle that is the site of photosynthesis.

Question 13

What is a chromosome?

Answer 13

A long, coiled molecule of DNA that carries genetic information in the form of genes.

Question 14

What are cilia?

Answer 14

Hair-like structures found on ciliated epithelial cells which waft substances across the surface of the tissue in one direction.

Question 15

What is a ciliated epithelial cell?

Answer 15

A type of epithelial cell that lines the surface of structures such as the respiratory tract and uterus.

Question 16

What is a concentration gradient?

Answer 16

The difference in concentration between two areas.

Question 17

Define denaturation in the context of enzymes.

Answer 17

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.

Question 18

What is diffusion?

Answer 18

The net spreading out of particles from a high concentration to a lower concentration (down their concentration gradient).

Question 19

What is a diploid cell?

Answer 19

A cell that contains two copies of each chromosome (i.e. a full set of chromosomes).

Question 20

What is an egg cell?

Answer 20

A specialised female sex cell involved in reproduction.

Question 21

What type of microscope uses a beam of electrons to produce an image?

Answer 21

Electron microscope.

Question 22

What is the emulsion test used for?

Answer 22

A chemical test that produces a cloudy emulsion when performed on lipids.

Question 23

Define an enzyme.

Answer 23

A biological catalyst that increases the rate of reactions in living organisms.

Question 24

What is a eukaryotic cell?

Answer 24

A type of cell found in plants and animals that contains a nucleus.

Question 25

What are flagella?

Answer 25

A long hair-like structure found on bacterial cells that is used for cell movement.

Question 26

What is a haploid cell?

Answer 26

A cell that contains a single copy of each chromosome (i.e. half the number of chromosomes).

Question 27

What does the iodine test indicate?

Answer 27

It produces a blue/black colour when iodine solution is added to a sample containing starch.

Question 28

What is a light microscope?

Answer 28

A type of microscope that uses a series of lenses to magnify the visible light reflecting off a specimen.

Question 29

What are lipases?

Answer 29

Enzymes that break down lipids into fatty acids and glycerol.

Question 30

Define lipid.

Answer 30

A large molecule that is synthesised from fatty acids and glycerol.

Question 31

What is the lock and key hypothesis?

Answer 31

A theory that describes how substrates must be the correct shape to fit the active site of an enzyme.

Question 32

What is magnification?

Answer 32

The number of times bigger an image appears compared to the original object.

Question 33

Fill in the blank: One micrometre is equal to _______.

Answer 33

× 10^-6 metre.

Question 34

Fill in the blank: One millimetre is equal to _______.

Answer 34

× 10^-3 metre.

Question 35

What is an organelle that is the site of respiration?

Answer 35

Mitochondria ## Footnote Mitochondria are often referred to as the powerhouse of the cell.

Question 36

What is a quantitative unit of length equal to 10^-9 metre?

Answer 36

Nanometre (nm) ## Footnote Nanometres are commonly used to measure wavelengths of light and dimensions of atoms.

Question 37

What organelle contains the genetic material of the cell?

Answer 37

Nucleus ## Footnote The nucleus controls the activities of the cell and is found in most eukaryotic cells.

Question 38

What is a specialised structure found inside a cell called?

Answer 38

Organelle ## Footnote Organelles perform specific functions vital for the cell's life.

Question 39

Define osmosis.

Answer 39

The diffusion of water molecules from a region of high water concentration to a region of lower water concentration across a partially permeable membrane ## Footnote Osmosis is crucial for maintaining cellular homeostasis.

Question 40

How is percentage change in mass calculated?

Answer 40

percentage change in mass = (final mass - initial mass) / initial mass × 100 ## Footnote This formula is used to determine the change in mass over a set period.

Question 41

What is a quantitative unit of length equal to 10^-12 metre?

Answer 41

Picometre (pm) ## Footnote Picometres are often used in atomic and molecular measurements.

Question 42

What are loops of DNA found in the cytoplasm of prokaryotic cells called?

Answer 42

Plasmid ## Footnote Plasmids can carry genes that provide bacteria with genetic advantages.

Question 43

What type of cell is found in bacteria and does not contain a nucleus?

Answer 43

Prokaryotic cell ## Footnote Prokaryotic cells are simpler and smaller than eukaryotic cells.

Question 44

What are enzymes that break down proteins into amino acids called?

Answer 44

Proteases ## Footnote Proteases play key roles in digestion and protein metabolism.

Question 45

What is a large molecule that is synthesised from amino acids?

Answer 45

Protein ## Footnote Proteins serve various functions, including structural, enzymatic, and regulatory roles.

Question 46

What is the speed at which reactants are converted into products known as?

Answer 46

Rate of reaction ## Footnote The rate of reaction can be affected by factors like temperature and concentration.

Question 47

Define resolution in a scientific context.

Answer 47

The smallest distance between two objects that can be distinguished ## Footnote Resolution is crucial in microscopy and imaging.

Question 48

What are the sub-cellular structures that are the site of protein synthesis?

Answer 48

Ribosomes ## Footnote Ribosomes can be found free in the cytoplasm or attached to the endoplasmic reticulum.

Question 49

What is a cell that has a structure adapted to its function called?

Answer 49

Specialised cell ## Footnote Examples include nerve cells, muscle cells, and blood cells.

Question 50

What describes the ability of an enzyme to catalyse only a particular reaction or set of reactions?

Answer 50

Specificity ## Footnote Specificity ensures that enzymes only interact with specific substrates.

Question 51

What is a specialised male sex cell involved in reproduction?

Answer 51

Sperm cell ## Footnote Sperm cells are designed for motility and fertilization.

Question 52

What organelle found in plant cells stores cell sap and supports the cell?

Answer 52

Vacuole ## Footnote Vacuoles play a crucial role in maintaining turgor pressure in plant cells.