Topic 1 - Definitions 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

Define active site.

Answer 2

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

Question 3

What is 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 does Benedict’s test detect?

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 is the Biuret test?

Answer 5

A chemical test that produces a purple colour when it is added to a solution containing protein.

Question 6

What does calorimetry measure?

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 synthesised 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 cell wall?

Answer 11

An outer layer made of cellulose that strengthens plant cells.

Question 12

What is the function of chloroplasts?

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.

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?

Answer 22

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

Question 23

Define 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

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 do lipases do?

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 (um) is equal to _______ metre.

Answer 33

x 10^(-6) metre.

Question 34

Fill in the blank: One millimetre (mm) is equal to _______ metre.

Answer 34

x 10^(-3) metre.

Question 35

What is mitochondria?

Answer 35

An organelle that is the site of respiration ## Footnote Mitochondria are often referred to as the powerhouse of the cell.

Question 36

Define nanometre (nm).

Answer 36

A quantitative unit of length. One nanometre is equal to ×10^-9 metre ## Footnote Used in measuring things at the molecular or atomic level.

Question 37

What is the function of the nucleus?

Answer 37

Contains the genetic material of the cell and controls the activities of the cell ## Footnote Found in most eukaryotic cells.

Question 38

What is an organelle?

Answer 38

A specialised structure found inside a cell ## Footnote Organelles perform specific functions necessary 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 Crucial for maintaining cell turgor and overall homeostasis.

Question 40

How is percentage change in mass calculated?

Answer 40

Percentage change in mass = (final mass - initial mass) / initial mass × 100 ## Footnote Used to quantify changes in mass over time.

Question 41

What is a picometre (pm)?

Answer 41

A quantitative unit of length. One picometre is equal to ×10^-12 metre ## Footnote Often used in fields like nuclear physics and chemistry.

Question 42

What is a plasmid?

Answer 42

Loops of DNA found in the cytoplasm of prokaryotic cells ## Footnote Plasmids can carry genes that provide advantages, such as antibiotic resistance.

Question 43

Define prokaryotic cell.

Answer 43

A type of cell found in bacteria that does not contain a nucleus ## Footnote Prokaryotic cells are generally simpler and smaller than eukaryotic cells.

Question 44

What are proteases?

Answer 44

Enzymes that break down proteins into amino acids ## Footnote Important for digestion and cellular processes.

Question 45

What is a protein?

Answer 45

A large molecule that is synthesised from amino acids ## Footnote Proteins perform a vast array of functions within organisms.

Question 46

What does rate of reaction refer to?

Answer 46

The speed at which reactants are converted into products ## Footnote Influenced by factors such as temperature and concentration.

Question 47

Define resolution in a biological context.

Answer 47

The smallest distance between two objects that can be distinguished ## Footnote Important in microscopy and imaging techniques.

Question 48

What are ribosomes?

Answer 48

Sub-cellular structures that are the site of protein synthesis ## Footnote Can be found free in the cytoplasm or attached to the endoplasmic reticulum.

Question 49

What is a specialised cell?

Answer 49

A cell that has a structure which makes it adapted to its function ## Footnote Examples include nerve cells and muscle cells.

Question 50

Define specificity in relation to enzymes.

Answer 50

Describes the ability of an enzyme to catalyse only a particular reaction or set of reactions ## Footnote This occurs because the substrate fits the active site of the enzyme.

Question 51

What is a sperm cell?

Answer 51

A specialised male sex cell that is involved in reproduction ## Footnote Sperm cells are designed for motility and delivering genetic material.

Question 52

What is the function of a vacuole?

Answer 52

An organelle found in plant cells which stores cell sap and supports the cell ## Footnote Vacuoles help maintain turgor pressure in plant cells.