Topic 1: Key Concepts in Biology

Question 1

Ciliated epithelial cell

Answer 1

Ciliated epithelial cells are specialized types of epithelial cells that line surfaces in the respiratory tract and uterus, equipped with cilia for moving mucus and other substances.

Question 2

Cilia

Answer 2

Cilia are hair-like structures found on the surface of certain epithelial cells, which help in wafting substances across the tissue in one direction.

Question 3

Chromosome

Answer 3

A chromosome is a long, coiled molecule of DNA that carries genetic information in the form of genes, essential for heredity and cellular function.

Question 4

Chloroplast

Answer 4

Chloroplasts are organelles found in plant cells where photosynthesis occurs, converting light energy into chemical energy stored in glucose.

Question 5

Cell wall

Answer 5

The cell wall is the outer layer composed primarily of cellulose that provides structural strength and support to plant cells.

Question 6

Cell

Answer 6

A cell is the basic structural and functional unit of all living organisms, serving as the building block of life.

Question 7

Carbohydrate

Answer 7

A carbohydrate is a large molecule that is synthesized from simple sugars, serving essential functions such as energy storage and structural support in organisms.

Question 8

Carbohydrases

Answer 8

Carbohydrases are enzymes that catalyze the breakdown of carbohydrates into simpler sugars, playing a key role in digestion.

Question 9

Calorimetry

Answer 9

Calorimetry is a method used to measure the heat transfer associated with a chemical reaction, providing insights into energy changes during the reaction.

Question 10

Biuret test

Answer 10

The Biuret test is a chemical test that indicates the presence of proteins, resulting in a purple color when a protein-containing solution is treated with the reagent

Question 11

Benedict’s test

Answer 11

The Benedict’s test is a chemical test used to identify reducing sugars, producing a color change that indicates the amount of reducing sugar present in a solution.

Question 12

Active transport

Answer 12

Active transport is the movement of substances from an area of low concentration to an area of high concentration across a membrane, requiring energy input from cellular respiration to overcome the concentration gradient.

Question 13

Active site

Answer 13

The active site refers to the specific region on an enzyme where the substrate binds, allowing the biochemical reaction to occur.

Question 14

Acrosome

Answer 14

The acrosome is the organelle at the tip of a sperm cell that contains enzymes necessary for digesting the egg cell membrane to facilitate fertilization.

Question 15

Millimetre (mm)

Answer 15

A unit of length equal to one thousandth of a metre, often used in various scientific measurements.

Question 16

Micrometre (μm)

Answer 16

A unit of length equal to one millionth of a metre, commonly used to measure cells and microorganisms.

Question 17

Magnification

Answer 17

The process of enlarging an image, calculated using the formula: image size = magnification × real size.

Question 18

Lock key hypothesis

Answer 18

A theory suggesting that substrates must have the correct shape to fit into the active site of an enzyme, similar to a key fitting a lock.

Question 19

Lipid

Answer 19

A large biological molecule synthesized from fatty acids and glycerol, commonly involved in energy storage and cellular structure.

Question 20

Lipases

Answer 20

Enzymes that catalyze the breakdown of lipids into fatty acids and glycerol.

Question 21

Light microscope

Answer 21

A type of microscope that uses a series of lenses to magnify specimens using visible light, providing lower magnification and resolution compared to electron microscopes.

Question 22

Iodine test

Answer 22

A chemical test that produces a blue/black color when iodine solution is added to a sample containing starch.

Question 23

Haploid cell

Answer 23

A cell that contains a single copy of each chromosome, representing half the number of chromosomes typical in gametes.

Question 24

Flagella

Answer 24

Long, hair-like structures found in certain bacterial cells used for movement.

Question 25

Eukaryotic cell

Answer 25

A type of cell found in plants and animals characterized by the presence of a nucleus and membrane-bound organelles.

Question 26

Enzyme

Answer 26

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

Question 27

Emulsion test

Answer 27

A chemical test that produces a cloudy emulsion to detect the presence of lipids in a sample.

Question 28

Electron microscope

Answer 28

A type of microscope that uses a beam of electrons and magnets to focus and produce highly magnified images of specimens with better resolution than light microscopes.

Question 29

Egg cell

Answer 29

A specialized female gamete involved in reproduction, which carries genetic material from the female parent.

Question 30

Diploid cell

Answer 30

A cell that contains two copies of each chromosome, representing a full set of chromosomes typical in somatic cells.

Question 31

Diffusion

Answer 31

The net movement of particles from an area of higher concentration to an area of lower concentration, moving down the concentration gradient.

Question 32

Denaturation

Answer 32

A permanent alteration in the shape of an enzyme caused by extreme pH or high temperatures, affecting its active site and preventing substrate binding.

Question 33

Concentration gradient

Answer 33

The difference in concentration between two areas, which drives the movement of substances during processes like diffusion.

Question 34

What is a vacuole?

Answer 34

An organelle found in plant cells that stores cell sap, providing structural support and regulating turgor pressure. Vacuoles play a crucial role in maintaining cell rigidity and storage of nutrients.

Question 35

What is a sperm cell?

Answer 35

A specialized male gamete involved in reproduction, characterized by its mobility and genetic contribution to the offspring. Sperm cells are essential for fertilization in sexual reproduction.

Question 36

Define specificity in enzymatic reactions.

Answer 36

The ability of an enzyme to catalyze a particular reaction; often determined by the fit of the substrate in the enzyme's active site. Specificity is critical for the proper functioning of metabolic pathways.

Question 37

What is specificity in enzymes?

Answer 37

The ability of an enzyme to catalyze a particular reaction; often determined by the fit of the substrate in the enzyme's active site.

Question 38

What is a specialised cell?

Answer 38

A cell that has undergone differentiation to perform a specific function within an organism, exhibiting unique structural features.

Question 39

What are ribosomes?

Answer 39

Sub-cellular structures responsible for protein synthesis, translating messenger RNA into polypeptide chains.

Question 40

What is resolution?

Answer 40

The smallest distance between two distinguishable points or objects; crucial in microscopy and imaging techniques.

Question 41

What is a protein?

Answer 41

A large biological macromolecule composed of one or more chains of amino acids, essential for various cellular functions.

Question 42

What is the rate of reaction?

Answer 42

The speed at which reactants are converted into products in a chemical reaction, often expressed in concentration change per unit time.

Question 43

What are proteases?

Answer 43

Enzymes that catalyze the breakdown of proteins into amino acids, playing crucial roles in digestion and metabolism.

Question 44

What is a prokaryotic cell?

Answer 44

A type of cell characteristic of bacteria, which lacks a membrane-bound nucleus and organelles.

Question 45

What is a plasmid?

Answer 45

A circular DNA molecule found in the cytoplasm of prokaryotic cells, often used in genetic engineering.

Question 46

What is a picometre?

Answer 46

A quantitative unit of length. One picometre is equal to ×10⁻¹² metres.

Question 47

How many metres are in one picometre?

Answer 47

One picometre is equal to ×10⁻¹² metres.