eukaryotic cells

what are the sub-cellular organelles in a eukaryotic cell?

• cell wall (plants + algae)

• cell surface membrane

• cytoplasm

• vacuole (plants)

• nucleus

• ribosomes

• mitochondria

• chloroplasts (plants + algae)

• rough endoplasmic reticulum (RER)

• smooth endoplasmic reticulum (SER)

• golgi apparatus

• lysosomes
  

what is the structure of a nucleus?

• nuclear envelope (double membrane)

• nuclear pores

• nucleolus

• nucleoplasm

what does the nuclear envelope do?

encloses the nucleus (acts as a membrane), separating it from the cytoplasm

what do nuclear pores do?

allow substances to move in and out of the nucleus

what does the nucleolus do?

• site of rRNA production

• synthesises and assembles ribosomes

what does the nucleoplasm contain?

chromatin and nucleolus

what is the structure/function of endoplasmic reticulum?

• membrane enclosed passageway for transporting material such as proteins

• substances leave the endoplasmic reticulum in small vesicles that carry them to the golgi apparatus

what is the structure of RER?

- folded, fluid-filled membrane
- membranes enclose flattened sacs called cisternae
- has surface bound ribosomes

what is the function of RER?

• where protein and glycoprotein synthesis occurs

• provides transport pathway for materials

what is the structure of SER?

• folded, fluid-filled membrane

• membranes enclose flattened sacs called cisternae

• lacks surface bound ribosomes

what is the function of SER?

• synthesises, stores, and transports lipids and carbs

• stores and transports protein made in RER to other organelles

what is the structure of the golgi apparatus?

• a stack of flattened membrane bound sacs called cisternae

• small rounded hollow structures called vesicles

what is the function of golgi vesicles?

• empty proteins and lipids into the lumen of the golgi apparatus

• store and transport modified proteins and lipids from the golgi apparatus to target cells

what is the function of the golgi apparatus?

• modifies proteins by adding non-protein components to them

  • adds carbs to proteins

• transport, modify and store lipids and proteins

• produces secretory enzymes

• secretes carbohydrates

• forms lysosomes

how are lysosomes formed?

when vesicles produced by golgi apparatus contain enzymes (such as protease, lipase and lysozymes)

what is the function of lysosomes?

- isolates enzymes from rest of cell before releasing them
- contains lysozymes which hydrolyse bacterial cell walls
- release enzymes outside of cell to destroy material around it (exocytosis)
- digest worn out organelles to reuse useful components
- completely breaks down cells after it dies (autolysis)

what is the structure of mitochondria?

- double membraned structure
- inner membrane is folded into cristae
- fluid-filled matrix

what is the function of mitochondria?

site of aerobic respiration which synthesises ATP

what does ATP stand for?

adenosine triphosphate

what is the function of the double membrane?

controls entry and exit of materials

what is the function/adaptation of cristae?

provides large S.A for attachment of enzymes for respiration

what does the matrix contain?

proteins, lipids, ribosomes and DNA
- ribosomes to synthesise their own proteins
- DNA to code for enzymes required for respiration

what is the structure of a chloroplast?

• double plasma membrane

• thylakoids

• grana

• stoma

• DNA

• ribosomes

what is the function of a double plasma membrane?

controls entry and exit of substances

what is the structure and function of thylakoids?

membrane-bound compartments which contain chlorophyll to absorb light for photosynthesis

what is the structure of grana?

• formed of multiple thylakoids stacked ontop one another

• joined together by lamellae

what is lamellae?

flat, thin parts of thylakoid membrane

what is the structure and function of stoma?

- fluid filled matrix
- starch grains are also found here
- where stage two photosynthesis occurs due to enzymes

what is the function of the ribosomes and DNA?

• ribosomes to synthesise proteins needed for photosynthesis

• DNA required for chloroplast replication

what is the cell wall in a plant cell made of?

cellulose

what is the cell wall in a fungi cell made of?

chitin, which is a nitrogen-containing polysaccharide

what is the function of the cell wall?

- to protect and support the cell
- to prevent osmotic lysis
- contributes to movement of H20 through plant

what is the structure of a vacuole?

• fluid filled sac bound by a single membrane (tonoplast)

• contains ions, sugars, amino acids, waste and (sometimes) pigments

what is the function of a vacuole?

- supports plants by making cells turgid
- sugar and amino acids act as a temporary food store
- pigments colour petals to attract pollinating insects