Biology - Organelles

Question 1

Organelles

Answer 1

A specialized compartment within a cell that carries out a specific function

Question 2

Cell membrane

Answer 2

• Acts as a barrier between intracellular fluid + extracellular fluid
• Controls what enters/exits the cell
• “semi-permeable membrane”

Question 3

Cell wall

Answer 3

• Made of cellulose that makes wall tough and strong
• Provides structural support + protection

Question 4

Nucleus

Answer 4

• Surrounded by double membrane
• Controls the activities of the cell
• Contains genetic info (DNA in chromosomes)

Question 5

Nuclear membrane

Answer 5

• Encloses the genetic info (DNA)

Question 6

Cytoplasm

Answer 6

• Area between cell membrane + nuclear membrane
• Contains substances (enzymes, ATP) until cell needs it
• Organelles are suspended

Question 7

Cytosol

Answer 7

Liquid that makes up cytoplasm which contains water, ions, and other small molecules

Question 8

DNA

Answer 8

• Found in nucleus entangled as chromatin
• Makes up genetic code of cell
• Is the hereditary information

Question 9

Nucleolus

Answer 9

• Site at which ribosomes are made
• No membrane

Question 10

Ribosomes

Answer 10

• Small, dark, spherical organelles
• Attached to membranes of RER or float freely in cytoplasm
• Makes proteins

Question 11

Endoplasmic reticulum

Answer 11

• Series of interconnected tubes that are formed by membranes
• Can be continuous with the nucleus membrane

RER; ribosomes attached + transports proteins that are made by ribosomes throughout cell

SER; makes lipids (fat), storage site for calcium ions

Question 12

Golgi bodies

Answer 12

• Loosely stacked sacs of membrane
• Often interconnected with ER
• Receive, modify, and transport protein
• Secrete mucus

Question 13

Vacuole

Answer 13

• Fluid filled spaces containing water and dissolved molecules
• Surrounded by single membrane called tonoplast
• Store food particles or waste
• In plants: provide support and storage space for water and starch

The vacuole in plant cells hold water, creating turgor pressure against the cell

Question 14

Mitochondria

Answer 14

• Rod shaped, 1-3 micrometers long
• Has double membrane
• Inner membrane is folded projections called cristae
• Fluid inside is the matrix
• Breaks down large macromolecules to release stored energy in a process called cellular respiration (glucose + O2 = CO2 + H2O + energy) which is converted to an easily usable form (ATP)

Question 15

Chloroplasts

Answer 15

• Oval, 5-10 micrometers long
• Has a double membrane + own DNA and ribosomes
• The # of chloroplasts vary (1-200) per cell
• Chrlorophyll (green pigment) in thylakoids trap sunlight and uses it to make glucose in photosynthesis (CO2 + H2O = glucose + O2)

Question 16

Lysosomes

Answer 16

• Found in both plant and animal cells
• Spherical organelles that are bound by single membrane
• Contain enzymes (type of protein) derived from RER
• Digest food molecules (food to cell to vacuole which joins up with lysosome)
• Destroy harmful chemicals that enter the cell by engulfing them
• When cell is old and doesn’t function, lysosomes act as suicide bags and breakdown, releasing their digestive enzymes into cytoplasm
• Enzymes are also used to destroy old + damaged organelles

Question 17

Centrioles

Answer 17

• Present in animal cells
• Short cylinders that occur in pairs at right angles called centrosome
• During mitosis; centrioles in centrosome travel to opposite poles of cell
• Also associated with produciton of cilia and flagella

Question 18

Animal cell?

Answer 18

Question 19

Plant Cell?

Answer 19

Question 20

Secretory Vesicles

Answer 20

Once sugar and fat molecules is added to protein, they collect in sacs that pinch off from the golgi; they remain in cytoplasm or move to cell membrane to be expelled