Cells

Question 1

Main difference between euk. and prok. cell

Answer 1

Prokaryotes lack nuclei, so their DNA is free-floating

Question 2

Name two groups of prok. and describe

Answer 2

Archaeabacteria - extreme environment, unique genes
Eubacteria- common places, typical structure

Question 3

Name “typical bacterium”

Answer 3

Escherichia coli

Question 4

Cell wall

Answer 4

The cell wall is a tough outer layer that surrounds and protects plant cells, giving them structure and support.

Question 5

Plasma membrane

Answer 5

The plasma membrane is a flexible layer that surrounds the cell, controlling what enters and exits the cell.

Question 6

cytoplasm

Answer 6

Cytoplasm is a gel-like substance inside the cell that holds the organelles and allows chemical reactions to happen.

Question 7

chromosome

Answer 7

In eukaryotic cells, chromosomes are linear and found inside a nucleus, while in prokaryotic cells, the chromosome is a single, circular DNA strand located in the cytoplasm, not enclosed in a nucleus.

Question 8

plasmid

Answer 8

Plasmids replicate independently and may be passed from one cell to another. They contain DNA

Question 9

ribosomes

Answer 9

produce proteins

Question 10

flagellum

Answer 10

enables cell to move

Question 11

pili

Answer 11

Pili are tiny hair-like structures on the surface of some bacteria that help them stick to surfaces or other cells.

Question 12

Name prokaryotic division and explain

Answer 12

Binary fission- DNA replicates and separates into two different areas of the cytoplasm, which then divide into two

Question 13

Name five differences between prok. eukaryt. cells

Answer 13

1. DNA is naked vs DNA is linear and hidden in nucleus
2. Cell division= Binary fission vs mitosis and meiosis
3. Ribosomes- 70S vs 80S
4. Organelles
5. Endoplasmic reticulum

Question 14

cell surface membrane

Answer 14

Is selectivelypermeable and controls the exchange of substances between the cell and its environment. Consists of protein and lipid

Question 15

Cytoskeleton (from what it is consist of)

Answer 15

Microtubules, filaments and fibers- gives cell physical support, involved in movement

Question 16

Nucleus

Answer 16

it is consist of nuclear envelope and pores. Nucleus contains chromatin

Question 17

Two forms of chromatin

Answer 17

1. Euchromatin- active DNA (loose, readable)
2. Heterochromatin - inactive DNA (tight, unreadable)

Question 18

Nucleoli

Answer 18

Nucleoli = ribosome factories inside the nucleus.

Question 19

Endoplasmis reticulum+ RER

Answer 19

The endoplasmic reticulum (ER) is a network of membrane-bound sacs called cisternae that helps make and transport materials in the cell.

• Rough ER has ribosomes on its cisternae and makes proteins.
• Smooth ER has smooth cisternae without ribosomes and makes fats (lipids) and helps with detoxification.

So, cisternae are the flattened or tube-like parts that form the structure of the ER.

Question 20

Mitochondria

Answer 20

Mitochondria are the cell’s powerhouses—they make energy by breaking down food.

They have two membranes, and the inner one is folded into cristae to increase surface area for energy production.
They produce energy in the form of ATP (adenosine triphosphate).
- The watery matrix inside contains DNA, ribosomes, calcium phosphate granules and enzymes

Question 21

Golgi apparatus and lysosomes

Answer 21

Golgi apparatus is like the cell’s post office—it modifies, process and packages proteins and lipids into vesicles for delivery inside or outside the cell. It is made of stacked, membrane-bound sacs called cisternae.

Lysosomes are the cell’s clean-up crew—they contain enzymes that break down waste, old cell parts, and harmful substances.

So in short:

Golgi apparatus = packaging center with cisternae

Lysosome = waste-digesting sacs with enzymes

Question 22

Cell wall (plant cell)

Answer 22

Function: Provides shape, support, and protection.
Main Components: Cellulose, pectin, lignin.
Middle Lamella: Sticky pectin-rich layer between cells, holds them together.
Membrane-lined Pores: Openings for material exchange.
Plasmodesmata: Tiny channels connecting cells for transport and communication.
Turgor Pressure: Water-filled vacuole pushes against the wall, keeping the cell firm.

Question 23

Chloroplast

Answer 23

Function: Site of photosynthesis, where light energy is converted into chemical energy (glucose).

Structure:
Outer membrane: Protects the chloroplast.
Inner membrane: Contains thylakoids, which are stacked into grana (where light reactions happen).
Stroma: Fluid surrounding the thylakoids, where the Calvin cycle occurs.
Chlorophyll: Green pigment in thylakoids that absorbs sunlight.

Question 24

Vacuole

Answer 24

Function:

Stores water, nutrients, and waste products.
Helps maintain turgor pressure, keeping the plant cell firm.

Structure:
Large, central sac surrounded by a membrane called the tonoplast.
Filled with cell sap (water, salts, sugars, and pigments).
Role in Growth: Helps plant cells expand by absorbing water.

Question 25

Differences Between Animal and Plant Cells

Answer 25

Cell Wall: Plant Cells: Have a cell wall made of cellulose. Animal Cells: No cell wall; only a plasma membrane. Chloroplasts: Plant Cells: Contain chloroplasts for photosynthesis. Animal Cells: No chloroplasts. Vacuole: Plant Cells: Have a large central vacuole for storage and turgor pressure. Animal Cells: Have small vacuoles (if any), mainly for storage. Shape: Plant Cells: Typically rectangular or box-shaped due to the cell wall. Animal Cells: Generally round or irregular in shape. Centrioles: Plant Cells: Lack centrioles (except in some lower plants). Animal Cells: Contain centrioles for cell division. Storage: Plant Cells: Starch Grains Animal Cells: Glycogen Granules

Question 26

Centrioles

Answer 26

Play a key role in cell division (mitosis and meiosis) by helping organize the spindle fibers that separate chromosomes.