Cells: Eukaryotic and prokaryotic cells, endosymbiosis, cell theory

Differences of prokaryotic and eukaryotic cells (6)

Differences:

prokaryotic: bacteria and archaea, eukaryotic: animals, plants and fungi

prokaryotic: DNA free in cytoplasm. eukaryotic: DNA in membrane bound nucleus

prokaryotic: no membrane bound organelles. eukaryotic: membrane bound organelles

prokaryotic has a decreased level in complexity (no membrane bound cells)

prokaryotic cell walls: peptidoglycon eukaryotic: (if any) chitin or cellulose

prokaryotic: smaller (0.1 - 0.5 micrometers) eukaryotic: bigger (up to 100 micrometers)

Cell theory (3)

All organisms are composed of one (unicellular) or more (multicellular) cells

Cells are the structural and functional unit of any living organism, and are where “MRS GREN” resides

All cells arise from prexisting cells via cell division

What are the necessary features of living organisms? (7)

Movement

Respiration

Sensitivity

Growth

Reproduction

Excretion

Nutrition

(MRS GREN)

Organelles

Sub-cellular structures in cells

What is endosymbiotic theory? (3)

Eukaryotic cells evolved due to a mutualistic relationship between 2 or more prokaryotic cells.

A larger prokaryotic cell with a flagellum eats a smaller prokaryotic cell without one. When the larger cell cannot digest the smaller anymore, it takes it into the vacuole

Name the structures in all prokaryotic cells (5)

Cytoplasm

Cell wall

Cell surface membrane

70s ribosomes

Loop of DNA

Name the optional extras of a prokaryotic cell (4)

Flagellum

Mesosome

Plasmid

Slime capsule

What is the consequence of the mutualistic relationship between the larger prokaryotic cell with the flagellum, and the smaller prokaryotic cell

Bigger one keeps the smaller one at the surface (because of flagellum’s grant of motility), for photosynthesis

Smaller carries out photosynthesis and produces oxygen, ATP, and glucose

Function of slime capsule

Protection from phagocytes engulfing cell

Plasmid (2)

Small circular molecule of DNA.

Contains additional genes for antibiotic resistance

Mesosome (2)

Infolding of cell surface membrane

Increases surface area for respiration

Flagellum

Microscopic appendage of cell that allows motility (movement)

Cytoplasm (2)

the solution where all of chemical reactions (metabolism) occur. where proteins are catalysed by enzymes

Prokaryotic cell walls (3)

Made of peptidoglycon

provides mechanical strength and support

prevents osmotic lysis in hypotonic solution

What kind of organisms have Prokaryotic cells (2)

bacteria, archaea

What kind of organisms do eukaryotic cells belong to (4)

Animals, plants, fungi. protoctista

Loop of DNA (3)

in prokaryotic cells

carries generic information in the form of genetic code which controls photosynthesis, and transcription of protein

essential genes involved in metabolism

70S Ribosomes (3)

In prokaryotic cells, mitochondria, and chloroplasts

Carry out translation (formation) of polypeptide chain

site of protein synthesis

Cell surface membrane (prokaryotic)

controls movements of molecules and ions in and out of cell

Evidence for endosymbiotic theory (4)

mitochondria and chloroplasts have:

• double membranes

• loop of DNA

• 70S ribosomes

mitochondria is a similar size to prokaryotic cells

Mitochondria function (3)

site of aerobic respiration

produces ATP to be hydrolysed for energy

which is needed for protein synthesis and exocytosis

chloroplast function (3)

site of photosynthesis

carbon dioxide + water with light = glucose + oxygen

glucose contains 2 molecules of ATP

nucleus function

• controls functions of cell

• carries DNA in chromatin

• contains essential genetic code for protein synthesis

• transcription of gene occurs, producing a molecule of mRna

• mRna leaves nucleus via nuclear pore

mRna

• messenger ribonucleic acid

• read by ribosomes and used to synthesis a proteins

• A: 70S Ribosomes

• B: Cell surface membrane

• C: Loop of DNA

• D: Plasmids

• E: Cell wall

• F: Mesosome

• G: Slime capsule

• H: Flagellum

Division of labour (3)

eukaryotic cells have many membrane bound organelles

this allows for the COMPARTMENTALISATION of cell

therefore different reactions happen in different organelles

Eukaryotic cell walls (5)

• Cellulose / chitin microfibrils

• pores are called plasmodenta

• Allows cytoplasms of adjacent cells to connect

• provided mechanical strength and support

• prevents osmotic lysis in hypotonic solutions

Thykaloid (2)

internal membrane in chloroplast which contains chlorophyll to absorb light energy

Granum

Stacks of thylakoids for increased SA for photosynthesis

Smooth endoplastic reticulum (3)

No ribosomes

Cisternae lined to nuclear envelope

synthesises, stores and transports lipids and carbohydrates

Ribosomes (3)

Made of large and small subunit

made of mRna and protein

Site of protein synthesis / translation: mRna is used to make polypeptide chain

Rough endoplasmic reticulum (3)

where folding of polypeptide chain occurs.

forming secondary and tertiary structure of protein

transports polypeptide chain / protein through cell

Vesicles (2)

pinches off of rough endoplasmic reticulum and transfer protein to golgi body

golgi body (3)

where protein is chemically modified and packaged

may involve addition of carbohydrate chain to form glycoprotein

also synthesises lysosomes

Secretory vesicle

transports functional protein to cell surface membrane

cell surface membrane (2)

controls molecules / ions going in and out of cell

vesicles fuse with membrane and release protein by exocytosis

exocytosis

moving large molecules out of cell to cell exterior

lysosome (5)

contains lumen, single membrane

contains hydrolitic enzymes

hydrolyses material digested by phagocytes

releases enzymes out of cell + digests worn out organelles + dead cells

programmed cell death / autolysis

autolysis

aka programmed cell death

breaking down of dead cells