eukaryotic cell structure

What are the three parts to the cell theory

1. All living things r composed of one or more cells

2. Cells = basic units of life

3. Cells are formed from pre-existing cells

2 types of cell structure

1. Eukaryotic

2. Prokaryotic

What are the structures found in a eukaryotic cell (11)

• cell surface membrane

• Nucleus

• Mitochondria

• Endoplasmic reticulum

• Ribosomes

• Cytoplasm

• Golgi apparatus

• Lysosomes

• chloroplasts

• Vacuole

• Cell wall

Cell surface membrane - functions (3)

• controls the exit ad entry of substances

• Allows different conditions in different environments

• Forms barrier + surrounds cell

Functions of nucleus (4)

• Holds genetic info for polypeptides production

• DNA replication

• Produces mRNA tRNA —> transcription

• Produces rRNA

Structure of nucleus (5)

• nuclear envelope and nuclear pores

• Contains chromatin (DNA wrapped in proteins(histones))

• Nucleolus

• nuclear envelope

• Nuclear pores

• Nucleuoplasm

• Nucleolus

• Contains linear DNA —> chromatin

Nuclear envelope (4)

• double membrane

• Surrounds nucleus

• Contains reactions within cell

• Outer membrane continuous with ER

Nuclear pores (2)

• allows passage of large molecules—> t/mRNA for photosynthesis

• 9000x

Nucleoplasm (2)

• jelly like material inside

• Chromatin found here

Nucleolus (4)

• small spherical region

• Centre of nucleus

• Makes rRNA

• Assembles ribosomes

Two types of endoplasmic reticulum

1. Smooth

2. Rough

Smooth ER (3)

• Tubular appearance

• No ribosomes

1. Synthesises

2. Stores

3. Transports

Carbs and lipids

Rough ER (3)

• continuous with nuclear envelope’s membrane

• Network of flattened sacks —> cisternae

• Has ribosome —> protein synthesis and transportation

What are the flattened sacks on RER called

Cisternae

Ribosomes - functions and (3)

• site of protein synthesis

  • Read mRNA to make proteins

• Found in

  • RER

  • Free in cytoplasm

2 types

1. 80S —> eukaryotic

2. 70S —> prokaryotic

Ribosomes - structure (2)

2 sub units

• Small

• Large

Made from rRNA and proteins

Golgi apparatus - structure (2)

Stacks of membranes that make up flattened sacs —> cisternae

Small rounded hollow structures —> vesicles —> bulge off as they are formed + transport

Golgi apparatus - function (3)

• modifies and transports lipids and proteins

  • Adding carbs —> makes glycoproteins and glycolipids

  • Labels them —> so correct location

Explain exocytosis and what is it

The active transport where cells secrete large molecules (mRNA, hormones enzymes) outside the cell

1. Modified protein/lipid by the Golgi

2. Transported in vesicles also fromed by the Golgi

3. Travel to cell surface

4. Fuse with membrane

5. Release contents outside cell

Structure of mitochondria (4)

• rod shaped

• Double membrane —> control entry and exit

  • Inner membrane —> folded to form extensions (cristae)

    • More SA

      • Helps with attachment of enzymes for respiration

• Middle = matrix

  • Contains

    • Lipids

    • Proteins

    • Ribosomes

    • DNA

Lysosomes (3)

• type of Golgi

• Contain lysozymes (enzymes)

  • Hydrolyse material ingested by cells —> digest worn out/invading cells

  • Eat up the broken down organelles thro endocytosis

• Digested material can be used or excreted

  • Used by the cell as building blocks to make other structures

What three organelles are only found in a plant cell

1. Chloroplast

2. Vacuole

3. Cell wall

Chloroplast - function

Photosynthesis

Starch storage

Mitochondria - function

Site of respiration

Produces ATP from aerobic

Chloroplast - structure (5)

• Chloroplast envelope —> double membrane

  • Selective barrier ←> storms and cytoplasm

• Granum

  • Stacks of 100x thylakoids

    • Disk like structures

    • Contains chlorophyll

    • More SA

      • Helps chlorophyll and enzymes to attach

• Stroma

  • Fluid that fills the matrix

    • Contains enzymes and proteins

      • used to make sugars for photosynthesis

• Starch grains

  • Found in stroma

  • Temporary energy store

    • At night

    • Starch = insoluble

      • No osmotic effect

  • Esp during excess production

• Has DNA and ribosomes

  • Makes proteins for photosynthesis fast

What are the contents on a chloroplast

1. Chloroplast envelope

2. Stroma

3. Granum —> made from thylakoids

4. Starch grains

5. DNA

6. Ribosomes

Vacuole - structure

• Tonoplast —> single membrane

• Contains

  • Mineral salts

  • Sugars

  • Amino acids

Vacuole - function

• helps cell rigidity

What are the contents of mitochondria

1. Matrix

2. Double membrane

3. Cristae

What two organelles contain cisternae

• Golgi

• RER

If a specialised cell had more mitochondria - what’s the specific function

Energy consuming tasks

If specialised cell had more endoplasmic reticulum - what’s specific function?

Secretory activities

Specialised cell = more lysosomes —> what’s specific task

Digestive process

Specialised cell = more chloroplasts —> what’s specific task

Photosynthesis

Specialised cell = more microvilli —> what’s specific task

More SA → more proteins attached for active transport