Biology - Review Qns - 2.1 & 2.2

Question 1

Core Term

The cell theory

3 Points

Answer 1

• All organisms are composed of cells (or the products of cells)
• All cells come from pre-existing cells
• The cell is the smallest living organisational unit.

Question 2

Definition

Eukaryotes

Answer 2

Include protists, fungi, plants & animals.

Eukaryotic cells contain membrane-bound organelles in the cell cytoplasm.

Question 3

Common features shared by all cells

4 items

Answer 3

Plasma membrane

Cytoplasm

Genetic material in the form of DNA

Ribosomes.

Question 4

Prokaryotic cells

4 characteristics

Answer 4

Simple structure

A nucleoid lacking a membrane

Scattered ribosomes

DNA mainly in a single-stranded loop in the nucleoid.

Question 5

Eukaryotic

4 Characteristics

Answer 5

Complex structure

Membrane-bound nucleus

Many organelles in the cell cytoplasm

DNA mainly in chromosomes in the nucleus.

Question 6

Plant cells

8 main structures

Answer 6

Nucleus

Vacuole

Golgi apparatus

Rough and smooth endoplasmic reticulum

Ribosomes

Plastids

Mitochondria

Cell wall

Question 7

Animal Cells

9 main structures

Answer 7

Nucleus

Ribosomes

Golgi apparatus

Rough and smooth endoplasmic reticulum

Vacuoles

Mitochondria

Lysosomes

Vesicles

Centrioles

Question 8

Organic versus Inorganic substances

Contrast these types

Answer 8

Organic substances:

• Contain carbon & hydrogen
• Are found in living things

Inorganic compounds

• Those that are not organic
• e.g. oxygen, water & carbon dioxide

Question 9

Main types of Organic Compounds

List of 4

Answer 9

Carbohydrates

Proteins

Nucleic acids

Lipids

Question 10

Describe

Biomacromolecules

Answer 10

Large organic molecules

Formed by joining together many smaller units (monomers)

Monomers form a chain or polymer.

Examples: polysaccharides, nucleic acids and proteins

Question 11

Core Term

Carbohydrates

5 points

Answer 11

• are an important source of chemical energy for

living organisms (e.g. glucose)

• are used as energy reserves in plants (e.g. starch) and animals (e.g. glycogen)
• form structural components such as cell walls (e.g. cellulose in plants).
• form part of both DNA and RNA
• combine with proteins and lipids to form glycoproteins and glycolipids, as in cell membranes.

Question 12

Core Term

Lipids

Answer 12

Fatty substances that are not soluble in water

Roles:

• the main component of cell membranes
• store energy
• play an important role as hormones

Question 13

Core Term

Nucleic acids

Answer 13

Contain the genetic material of all organisms.

There are two types:

• DNA-carries the ‘instructions’ required to assemble proteins
• RNA-plays a major role in the manufacture of proteins.

Question 14

Functions of Proteins

List of 5

Answer 14

Catalyse cellular reactions

Play an important role as hormones

Act as carrier molecules

Form structural components in organisms

Play an important role in the immune system (e.g. antibodies and antigens)

Question 15

Important properties of water

Answer 15

Cohesiveness

Surface tension

Heat capacity

pH

Question 16

Main source of Carbon?

Answer 16

Atmospheric carbon dioxide

Question 17

Nitrogen

Answer 17

Component of all proteins

“fixed’ from the atmosphere by certain bacteria

Question 18

Minerals

Answer 18

Form important parts of organic molecules such as enzymes and structural molecules