2.1 Cells

Question 1

Nucleus

Answer 1

Information centre of eukaryotic cell
- dna is stored, replicated and copied into mRNA

Question 2

Nuclear pores

Answer 2

Gaps in the nuclear envelope that allow substances to move in and out of the nucleus

Question 3

Nuclear envelope

Answer 3

Double membrane that separates the contents of the nucleus form the cytoplasm

Question 4

Nucleolus

Answer 4

Part of the nucleus that produces ribosomes

Question 5

Cell surface membrane

Answer 5

Phospholipid bilayer that contains cholesterol and proteins
- it is a fluid layer that surrounds the cell and enables it to communicate with other cells (cell signalling)
- detect and respond to changes in the environment
- physical barrier - controls what enters and exits the cell

Question 6

Extracellular matrix

Answer 6

The material in between cells that holds tissues together
- usually made of scaffolding proteins such as collagen
- important for cell signalling

Question 7

Rough endoplasmic reticulum (RER)

Answer 7

Site where proteins are made, folded and moved to Golgi body

Question 8

Smooth Endoplasmic reticulum

Answer 8

• lipid and steroid synthesis
• drug detoxification

Question 9

Ribosomes

Answer 9

Make new proteins from mRNA through translation (protein synthesis)
- found as free ribosomes in cytoplasm and attached to rough ER

Question 10

Golgi body

Answer 10

Modifies, packages and directs newly made proteins to where they are needed

Question 11

Cytoplasm

Answer 11

Site of chemical reactions
- viscous aqueous fluid containing water, proteins and other inorganic molecules and organelles

Question 12

Mitochondria

Answer 12

Supply chemical energy to the rest of the cell
- they are surrounded by a double membrane

Question 13

Microfilaments

Answer 13

Made from repeating actin subunits
- responsible for cell movement and changes in shape, making muscle contractions possible
- thinnest component of the cytoskeleton

Question 14

Vacuole

Answer 14

Internal, surrounded by a membrane, which cells use for storing food and waste

Question 15

Microtubules

Answer 15

Small, tubular assemblies of protein
- Help maintain cell’s internal structure and move organelles and cytoplasm using molecular motors
- part of cytoskeleton

Question 16

Centrioles

Answer 16

A pair of organelles that organise microtubules into spindles on which chromosomes are separated when cells divide

Question 17

Lysosomes

Answer 17

Membrane bound organelles that digest other organelles (e.g. Bacteria)
- contain hydrolysis enzymes (lysozymes)