2.1 Cell Structure

What is the organelle labelled A?

Cell surface membrane

What is the organelle labelled B?

Mitochondrion

What is the organelle labelled C?

Nucleus

What is the organelle labelled D?

Ribosomes

What is the organelle labelled E?

Rough endoplasmic reticulum

What is the organelle labelled F?

Smooth endoplasmic reticulum

What is the organelle labelled G?

Golgi apparatus

What is the organelle labelled H?

Lysosome

What is the organelle labelled I?

Chloroplast

What is the organelle labelled J?

Cell wall

What is the organelle labelled K?

Vacuole

Describe the structure of the nucleus

Nuclear envelope
- double membrane
- has nuclear pores

Nucleoplasm

Nucleolus (inner region)

Protein linear DNA
- histone-bound
- chromatin → condensed
Chromosome → highly condensed

Function of the nucleus

• carries genetic information which codes for polypeptides (proteins)

• site of transcription

• nucleolus makes ribosomes/ rRNA
  

Describe the structure of a ribosome

Made of ribosomal DNA and protein

Function of a ribosome

site of protein synthesis - translation

Function of sER

synthesises and processes lipids e.g. cholesterol and steroid hormones

Function of rER

ribosomes on surface synthesise proteins. proteins packages into vesicles for transport

Function of Golgi apparatus

• modifies protein e.g. adds carbohydrates to produce glycoproteins

• modifies lipids e.g. adds carbohydrates to make glycolipids

• produces lysosomes

Function of Golgi vesicles

transports proteins and lipids to their required destination

Structure of lysosomes

Has a membrane and hydrolytic enzymes

Function of lysosomes

release hydrolytic enzymes (lysozymes) to hydrolyse pathogens

Structure of mitochondria

Outer membrane, inner membrane folded to form cristae, matrix containing ribosomes and circular DNA

Function of mitochondria

• site of aerobic respiration

• to produce ATP for energy release

Structure of chloroplasts

double membrane, stroma containing thylakoid membrane, ribosomes, circular DNA and starch granules, lamella and grana.

Thylakoids stack up to form ___ in chloroplasts

grana

function of chloroplasts

absorbs light energy for photosynthesis

Structure of cell walls in plants

composed of cellulose in plants/ algae but composed of chitin in fungi

function of cell wall

provides mechanical strength to cell to prevent bursting under pressure due to osmosis

Definition of a tissue

Group of specialised cells with a similar structure working together to perform a specific function, often with the same origin.

Definition of an organ

Aggregations of tissues performing specific functions.

Definition of organ system

Group of organs working together to perform specific functions.