Cell structure

Function of nucleus

contains the genetic material

Function of smooth endoplasmic reticulum (SER)

Transport and synthesis of lipids, carbohydrates, and steroids

Function of lysosome

contain hydrolysing enzymes

Function of ribosome

protein synthesis

Features of mitochondria

• surrounded by double membrane with the inner membrane folded to form cristae

• contains enzymes needed for aerobic respiration, producing ATP

• small circular pieces of DNA

• Ribosome also found in the matrix for replication

• similar size to mitochondria

Role of mitochondria

site of aerobic respiration for ATP

Features of Chloroplasts

• double membrane

• membrane-bound compartments called thylakoids containing CHLOTOPHYLL stack to form structures called grana

• Grana joined by lamellae (thin and flat thylakoid membranes)

• contain small circular DNA, ribosomes (synthesise proteins needed in chloroplast replication and p/s)

Functions of chloroplast

site of photosynthesis:

• light dependent stage takes place in the thylakoids

• light independent stage takes place in the stroma

Roles of cytoskeleton

• mechanical strength

• support the cell

• maintaining cell shape

• movement of cilia and undulipodia

• cytokinesis

• movement of vesicles

How organelles work together to produce and release the protein molecules from the cells

1. Nucleus that contains gene for proteins is the site of transcription

2. The ribosomes in RER is the site of protein synthesis and translations occurs

3. Proteins are transported in the vesicles

4. to Golgi apparatus where it processes, modifies and repackages the proteins into secretory vesicles

5. vesicles move along the cytoskeleton

6. Vesicles fuse to the cell surface membrane

7. secretion by exocytosis

Role of Golgi apparatus

1. Modifies proteins and lipids

2. repackages into vesicles

3. make lysosomes

4. exocytosis

define magnification

number of times larger the image is compared to object

define resolution

ability to distinguish between two separate points 

resolution of a light microscope

50-200nm / 0.05-0.2 um

resolution of a transmission electron microscope

0.05-1.0nm

roles of membranes inside cells

• isolation of contents of organelles

• form organelles e.g. mitochondria, ER, nucleus, lysosomes, golgi, chloroplast

• site for attachment of enzymes 

How vesicles are moved from one organelle to another

• cytoskeleton

• provide pathways for movement

• vesicles move along microtubules

• microtubules extended and uses ATP

How are proteins ensure that a vesicle is transported to the correct target organelle.

• receptors only on target organelle

• protein has a specific shape that is complementary to the receptor.

how extracellular enzymes are secreted from the cells

• exocytosis

• vesicles fuse to the cell surface membrane

why the nuclear envelope contains pores

to allow movement of substances in and out of nucleus

preparing slide
how to stain the sample

1. use pipette to place blood on slide

2. place blood near one end of slide

3. put cover slip to spread blood across slide

4. coverslip at an angle

1. use pipette to place a drop of stain onto slide

2. place coverslip

3. ensuring there are no air bubbles

why staining

• to be able to see more easily

• to increase contrast to make nuclei visible

ribosomes in Eukaryotic and Prokaryotic

Prokaryotic cells- 70S ribosomes

Eukaryotic cells- 80S ribosomes

Features of Rough Endoplasmic Reticulum (RER)

• found in plant and animal cells (Eukaryotic)

• surface covered in ribosomes

• formed from continuous folds of membrane continuous with the nuclear envelope

Roles of the membrane in the RER

• separating proteins from cell cytoplasm

• Hold ribosomes in place

Means of cell division

Animal- cytokinesis

Plant- cytokinesis

Yeast- budding

Bacterium- binary fission

structural features of mitochondria

• have double membrane

• with the inner membrane folded to form cristae

• circular pieces of DNA

• ribosomes

mitochondria

• respire aerobically

• produces more ATP

• ATP used for active transport

• increases the rate of metabolism

process and organelles involved in the translation of proteins from RNA

• mRNA transported out of nucleus

• to ribosome

• Translation/ protein synthesis occurs at the ribosome

• tRNA brings specific amino acid

• Peptide bond forms between adjacent amino acids

• Polypeptide protein processed through Golgi apparatus (transported in the vesicle) 

ways in which tubulin (movement of cell) is essential to protein synthesis and protein secretion in eukaryotic cells

• movement of vesicles from RER to golgi

• Movement of secretary vesicles from golgi to plasma membrane

how does cytoskeleton moves organelles around the cell

move by protein motors/ using microtubules 

function of the nuclear pores

allow communication between nucleus and cytoplasm

function of vacuole

take up water

Microscopes

laser scanning confocal microscope vs electron microscope

LSCM has a lower resolution than EM

Explain how to measure the diameter of the nucleus of one of the white blood cells when observing the cells through a light microscope

1. use eyepiece graticule

2. calculate graticule using stage micrometer

3. measure the diameter of nucleus in epu

4. take repeat measurements and calculate a mean diameter

5. use calibrated epu to calculate the diameter in um

benefits of using stains

• increase contrast

• more internal structures visible

• because organelles bind to stain

explain why it is important to use a differential stain when examining a blood smear under the microscope

• to identify cells

• to identify organelles

• RBC visible without stain due to haemoglobin

• in contrast, WBC needs staining to be visible