AP Biology Organelles & Cell Size

University:
Winston-Salem Forsyth County Schools
Course:
AP Biology
Academic year:

2023
Views:

292

Pages:

3
Author:

aterizareofn

Organelles & Cell Size Cellular Organelles ● Nucleus ○ Contains hereditary information/DNA/chromosomes ○ Site of RNA synthesis ● Ribosomes ○ Made up of ribosomal RNA (rRNA) & protein ○ They synthesize protein according to an mRNA sequence that is transcribed from the instructions found in DNA ○ They are found in ALL living things (prokaryotes & eukaryotes -> reflects common ancestry) ○ They are not membrane bounded organelles ● Endoplasmic Reticulum (ER) ○ It occurs in 2 forms (smooth & rough) ○ Free ribosomes are used to make protein that will be used in the cell itself ■ Rough ER: Protein Synthesis (since ribosomes are attached) & manufactures secretory proteins (that the ribosomes made) in transport vesicles & sends them to the Golgi body C ● Compartmentalizes the cell ■ Smooth ER: Used to detoxify poison/alcohol/waste (liver) & creates lipids (NO ribosomes) ● Golgi body ○ A membrane-bound structure that consists of a series of flattened membrane sacs ○ It folds & chemically modifies the newly synthesized proteins from the ER & packages/ships them in transport vesicles ○ Cis face = imports the protein ○ Trans faces = exports the protein ● Mitochondria ○ Produces ATP ○ It has a double membrane (the space between the 2 membranes is called the Intermembrane space) ■ Inner membrane: Highly folded (allows for greater surface area → more ATP to be synthesized ) & compartmentalization for different metabolic reactions) ■ Outer Membrane: Smooth ○ The Krebs cycle occurs in the matrix of the mitochondria ○ The Electron Transport Chain (ETC) & ATP synthesis occur on the inner mitochondrial membrane ● Lysosomes ○ They are membrane-enclosed sacs that contain hydrolytic enzymes (used for all the organelle’s functions) ○ Break down any foreign particles and worn out organelles ○ Digest food vacuoles ○ Can initiate cell death (apoptosis) ● Vacuoles ○ A membrane-bound (tonoplast) sac that is found in plant & animal cells ○ Purpose: Storage ○ Pumps out extra water (helps avoid swelling) ○ Release of macromolecules/waste ■ Plants: helps maintain turgor pressure by storing water & solutes ■ Animals: pumps out water to maintain equilibrium & stores food/waste products (until they can be digested/removed from the cell) ● Chloroplast ○ Specialized organelles that are found in plants (site of photosynthesis) ○ Have a double outer membrane ○ Stroma (the fluid within the inner chloroplast): Where carbon fixation/dark reactions of photosynthesis occurs ○ Thylakoid (stacks of them = granum): Where the light absorbing reactions of photosynthesis take place (contains chlorophyll & ETC proteins which make up the photosystems). Cell Size ● If cells have a large Surface Area to Volume ratio (high SA & low Volume) they will be more efficient in exchanging materials with the environment ● As cells increase in volume, the demand for internal resources increases ● Many complex structures fold so that they can increase their SA to Volume ratio ● SA can be increased through microvilli