cell structure

what is a eukaryote?

an organism whose DNA is found in a nucleus

what are organelles?

a sub-cellular part or component of a cell

what is the cytoplasm made of?

cytosol which is water, salts, an organic molecules

what is a prokaryotic cell?

single celled organism with a simple structure.

It has a single internal area called the cytoplasm

what’s a eukaryotic cell?

more complex internal structure which contains a membrane bound nucleus and cytoplasm.

It contains many membrane bound organelles

what make up multicellular organisms?

eukaryotic cells

what is the cytoskeleton made of?

• microtubule

• intermediate fibres

• micro filaments

what is the function of the cytoplasm?

the site of many cellular reactions

why is the cytoplasm divided in eukaryotes?

to provide specific environments for the different cellular reactions.

what is the cytoplasm divided into?

many different membrane bound organelles.

what does the nucleus contain?

genetic information as DNA molecules

what does DNA control?

the synthesis of all proteins needed by the cell. Many of these proteins are the enzymes necessary for metabolism

what is the nucleolus

an area within the nucleus

what is the nucleolus responsible for?

producing ribosomes

what is the nucleolus made up off

proteins and RNA

what does RNA produce?

ribosomal RNA (rRNA) which combines with proteins to form ribosomes

why is the mitochondria considered an essential organelle to to eukaryotic cells?

it is the site of the final stage of cellular respiration where the energy is released by the production of ATP

what does the number of mitochondria in a cell reflect?

the amount of energy the cell uses. Very active cells have lots of mitochondria

how many membranes does the mitochondria have?

2, double membraned

what is the inside of the mitochondria called?

the matrix

why is the inner membrane of the mitochondria folded?

increase surface area

what are vesicles?

membrane bound sacs

what roles do vesicles have?

usually storage and transport.

what are lysosomes?

special types of vesicles

what do lysosomes contain?

hydrolytic enzymes

what is the hydrolytic enzyme in lysosomes used for?

breaking down waste materials in the cell such as old organelles

how do lysosomes play a part in the immune system?

they are responsible for breaking down pathogens ingested by phagocytic cells

what’s flagella like?

whip like

what’s cilia like?

hair like

what are flagellum used for?

• enable cell motility

• sometimes as sensory organelles to detect chemical change in environment

where is stationary cilia usually found?

surface or sensory cells as in the nose

where can mobile cilia be found?

lining the trachea

how does mobile cilia work?

beats in a rhythmic manner which creates a current causing fluids or objects to be moved across the surface

where is the cytoskeleton found?

throughout the cytoplasm of all eukaryotic cells

what is the cytoskeleton?

a network of fibres needed to shape and create stability in the cell

what can the cytoskeleton control?

cell movement and the movement of organelles within cells

what are organelles held by?

by the cytoskeleton

what are microfilaments

contractile fibres that are made from protein actin

what are microfilaments responsible for?

cell movement

what are micro tubules

globular tubulin proteins that form tubes that determine the shape of the cell

what are spindle fibres involved in cell division made from?

microtubules

what do microtubules act as?

act as tracks for the movement of organelles, especially vesicles around the cell

what’s the function of intermediate fibres?

they give mechanical strengths to cells to maintain their integrity

where are centrioles not found?

flowering plants and most fungi

what is centrioles part of?

the cytoskeleton

what are centrioles made of?

microtubules

what are two associated centrioles called?

centrosomes

what is centrosomes involved in?

assembly and organisations of the spindle fibres needed during cell divisions

which components are involved in protein synthesis?

• endoplasmic reticulum

• ribosomes

• golgi apparatus

what is the endoplasmic reticulum

a network of membranes enclosing flattened sacs called cisternae.

what is the endoplasmic reticulum connected too?

the nuclear envelope

what is the smooth endoplasmic reticulum responsible for?

lipids and carbohydrates synthesis and storage

what is the rough endoplasmic reticulum responsible for?

responsible for synthesis and transport of protein

what does the rough endoplasmic reticulum have attached to it?

ribosomes found on its surface

what are ribosomes constructed of?

RNA molecules

what is the ribosomes needed for?

site of protein synthesis (build up of protein)

do ribosomes contain membrane?

no, they do not contain a membrane

structure of golgi apparatus?

compact structure made of cisternae that does not contain ribosomes

what is the role of the golgi apparatus?

modifying proteins and packing them into vesicles

when is a vesicle considered a secretory vesicle?

if the proteins leave the cell

when is a vesicles considered a lysosomes?

if it stays inside the cell

the steps for protein production

1. Disks

is the cell membrane an organelle?

no. it’s not an organelle but a mean for compartmentalisation

What are proteins packaged into after being synthesised on the RER?

Transports vesicles

Where do the transports vesicles containing synthesised protein move too after budding off the RER?

The Golgi apparatus

How does the transports vesicles containing synthesised proteins move too after budding the Golgi apparatus?

Via the transports function of the cytoskeleton

On which side do the transports vesicles fuse too to the Golgi

Cis face

What happens to the transport vesicle once it fuses with the cis face?

once the transport vesicle fuses onto the cis face, the protein is structurally modified

What happens to proteins that enter the Golgi apparatus and are further modified?

The modified protein will leave the Golgi apparatus in a vesicle from its trans face

How do secretory vesicle leave the cell?

Secretory vesicles leave the cell by moving toward and fusing with the cell-surface membrane and releasing the content by exocytosis

What is cellulose?

Cellulose is a carbohydrate substance that makes up the cell wall

What is ‘turgor’?

Tutor is the state of turgidity and resulting rigidity of cells or tissues, typically due to the absorption of fluid

Why are plants cells rigid/sturdy?

Due to their cell wall

What is a large permanent vacuole?

A large permanent vacuole is a memberane lined sac found in the cytoplasm. They contain cell sap

How does a large permanent vacuole help a plant cells rigid?

Large permanent vacuole help maintain the plant turgor so that the components of the cell are pushed against the cell wall

What’s the membrane surrounding the vacuole called?

Tonoplast

Why can small molecule pass through the vacuole but larger ones cannot?

The tonoplast of the vacuole is partially permeable

Do animals cells have vacuole?

Yes, some vacuoles appear but are small and not permanent

What is the chloroplast responsible for?

The chloroplast is responsible for photosynthesis

Where is the chloroplast found?

The chloroplast is found in the green part of plant cells

How is chloroplast similar to the mitochondria?

They are both doubled-membraned

What’s the fluid inside the chloroplast called?

Stroma

What are thylakoids?

Thylakoids are a network of membranes made up of flattened sacs

What is a stack of thylakoids called?

A stack of thylakoids is called a granum

What’s the plural of granum?

Grana

What is each grana joined together by?

A membrane called lamellae

What does the grana contain?

The grana contains photosynthetic pigment molecule chlorophyll

Where is starch produced by photosynthesis found?

Found as starch grains within the stroma

how is the chloroplast able to make its own protein?

The chloroplast can make its own proteins because it contains DNA and ribosomes

What do the internal membranes in the chloroplast do?

The internal membranes in the chloroplast increase the surface area needed for photosynthesis

What is a plasmodesma?

A plasmodesma is a channel between plant cell wall

What’s plural of plasmodesma

Plasmodesmata

What does the plasmodesmata enable the plant cell to do?

The plasmodesmata allows molecules and substances to move back and forth as needed

What is endosymbionit?

Endosymbionit is an organism that lives inside another cell or organism

What is an extremophile?

An extremophile is an organism that thrives in extreme conditions

What is an operon?

An operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter

What domain do most extremophile fall under?

Archaea

what type of organism are prokaryotes?

unicellular

where is the dna found in a prokaryote?

The DNA in a prokaryote is found loose in the cell

Are the organelle in a prokaryote membrane bound?

No