Week 5 - Cell Structure

Question 1

Mitochondrion

Answer 1

The “powerhouse” of the cell; site of cellular respiration and ATP production.

Question 2

Chloroplasts

Answer 2

Organelles in plant cells that carry out photosynthesis; contain chlorophyll.

Question 3

Nucleus

Answer 3

Control center of the cell; stores DNA and coordinates gene expression and replication.

Question 4

Endoplasmic Reticulum (ER)

Answer 4

Network of membranes involved in protein and lipid synthesis.

Question 5

Rough ER

Answer 5

Studded with ribosomes; involved in protein synthesis and folding.

Question 6

Smooth ER

Answer 6

No ribosomes; involved in lipid synthesis, detoxification, and calcium storage.

Question 7

Nuclear Envelope

Answer 7

Double membrane surrounding the nucleus; contains nuclear pores for molecule transport.

Question 8

Golgi Apparatus

Answer 8

Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Question 9

Lysosome

Answer 9

Contains digestive enzymes to break down macromolecules, waste, and damaged organelles (in animal cells).

Question 10

Vacuole

Answer 10

Storage organelle (especially large in plant cells) for water, ions, waste, and nutrients.

Question 11

Contractile Vacuole

Answer 11

Pumps out excess water to maintain osmotic balance in protists/freshwater organisms.

Question 12

Peroxisome

Answer 12

Breaks down fatty acids and detoxifies harmful substances (e.g., hydrogen peroxide).

Question 13

Cell Wall

Answer 13

Rigid outer layer (plants, fungi, bacteria); provides structure and protection; made of cellulose in plants.

Question 14

Extracellular Matrix (ECM)

Answer 14

Network of proteins and carbs outside animal cells; supports and connects cells.

Question 15

Lignin

Answer 15

A complex polymer in plant cell walls that adds rigidity and waterproofing (especially in wood).

Question 16

Cytoplasm

Answer 16

The jelly-like fluid + organelles inside the cell (excluding the nucleus).

Question 17

Cytoskeleton

Answer 17

A dynamic network of protein fibers that gives the cell shape, structure, and mobility.

Question 18

Microtubules

Answer 18

Hollow tubes; involved in cell division, intracellular transport, and cilia/flagella movement.

Question 19

Microfilaments (Actin Filaments)

Answer 19

Thin, solid filaments; support cell shape and muscle contraction.

Question 20

Intermediate Filaments

Answer 20

Ropelike fibers that provide mechanical strength and structural support.

Question 21

Ribosomes

Answer 21

Sites of protein synthesis; can be free in cytoplasm or bound to rough ER.

Question 22

Glycosome

Answer 22

Organelle (in some protozoa) that contains enzymes for glycolysis.

Question 23

Plastids

Answer 23

Plant cell organelles (like chloroplasts, chromoplasts, amyloplasts) with various functions including photosynthesis and storage.

Question 24

Centriole

Answer 24

Cylindrical structure in animal cells; helps organize microtubules and form spindle fibers during mitosis.

Question 25

Anterograde

Answer 25

Movement from the center of the cell (usually the ER or Golgi) toward the plasma membrane (outward).

Question 26

Retrograde

Answer 26

Movement from the plasma membrane or outer cell regions back toward the center, like the Golgi or ER.

Question 27

Kinesin

Answer 27

A motor protein that moves cargo in the anterograde direction — toward the plus (+) end of microtubules (usually toward the cell periphery).

Question 28

Dynein

Answer 28

A motor protein that moves cargo in the retrograde direction — toward the minus (−) end of microtubules (usually toward the cell center, like the nucleus).