Human Cell Structure

Question 1

Plasma (cell) membrane

Answer 1

Partially permeable membrane that controls entry and exit of the cell

Question 2

Nucleus

Answer 2

Contains DNA and is the site of of DNA replication (and transcription)

Question 3

Nuclear envelope

Answer 3

Double plasma membrane that surrounds the nucleus & contains pores for mRNA movement

Question 4

Nucleolus

Answer 4

Spherical structure in the Nucleus where RNA and ribosomes are synthesised

Question 5

Golgi apparatus

Answer 5

A stack of membrane sacs where proteins, carbohydrates & lipids are modified and transported

Question 6

Mitochondria

Answer 6

Site of aerobic respiration (& production of ATP)

Question 7

Rough endoplasmic reticulum

Answer 7

Double membrane sacs that extend to the nucleus envelope to allow ribosomes to attach for protein synthesis

Question 8

Smooth endoplasmic reticulum

Answer 8

Double membrane sacs extending to the nucleus envelope to the site of lipid & carbohydrate storage and transport

Question 9

Ribosome

Answer 9

Site of protein synthesis, made up of proteins and RNA

Question 10

Cytoskeleton

Answer 10

A network of proteins which provide structural support & allow molecules/organelle to move in and out of the cell

Question 11

Lysosome

Answer 11

Contains hydrolytic enzymes (produced by golgi apparatus), membrane bound

Question 12

Cytoplasm

Answer 12

Water based jelly like substance found in the cell where most chemical reactions occur

Question 13

Simple Diffusion

Answer 13

The downhill movement of molecules or ions down a concentration gradient across a membrane

Question 14

Facilitated Diffusion

Answer 14

The downhill movement of larger ions/molecules down a concentration gradient across a membrane through the use of protein carriersor channel proteins

Question 15

Active Transport

Answer 15

The uphill movement of ions/molecules across a membrane against the concentration gradient using energy (from the hydrolysis of ATP)

Question 16

Osmosis

Answer 16

The downhill movement of water molecules across a semi-permeable membrane down the concentration membrane

Question 17

Endocytosis

Answer 17

When the cell membrane engulfs material, to bring it into the cell inside a vesicle

Question 18

Exocytosis

Answer 18

When a vesicle is fused to the plasma membrane to allow molecules to be released from the cell