Unit 3: Cells

Question 1

Cell theory

Answer 1

• All living things are made up of cells
• Cells are the basic units of structure and function in living things
• New cells are produced from pre-existing cells (via mitosis/ cell division)

IMPORTANCE: it allows us to understand how living things are created, grow, and die.

Question 2

Role of Microscope

Answer 2

• Cells were discovered via microscope (by Robert Hooke)
  -Most microscopes use lenses to magnify the image of an object by focusing light or electrons.

Question 3

Compound Light Microscope

Answer 3

Light passes through an object and two lenses

Question 4

Electron Microscopes

Answer 4

Use beams of electrons instead of light. This allows for much clearer and more detailed imaging for the study of smaller things.

1) Transmission electron microscopes produce flat, two-dimensional images.

2) Scanning electron microscopes
produce three-dimensional images of the specimen’s surface.

Question 5

Difference Between Prokaryotes and Eukaryotes

Answer 5

Nucleus: Prokaryotic are cells which don’t have a nucleus, while Eukaryotic cells do.

Complexity: Eukaryotic cells typically are more complex and specialized as they evolved from prokaryotic cells

However, they both carry out essential processes of life (growth, reproduction, response to stimuli) and contain genetic material

Question 6

Animal and Plant Cell Comparison

Answer 6

Similarity: Both have DNA, cytoplasm, + cell membrane. They also both have a nucleus, allowing for both cells to contain and protect its DNA.

Difference: Plant cells have a rigid and organized cell wall while animal cells have a more flexible cell membrane - these different structures allow for both cells to regulate their intake of nutrients and water from outside of the cell in their different ways.
- animals have lysosomes
- plants have chloroplasts + larger central vacuole to store its nutrients

Question 7

Nucleus Function + Structure

Answer 7

Function:
-AKA “control center” -
Houses DNA
-Where protein synthesis begins - help ribosomes in their protein-making process by turning DNA that enters into RNA that exits.

Structure: Has its own “membrane” known as the nuclear envelope and -has a nucleolus where ribosomes are made

Question 8

Vacuole Role

Answer 8

Organelle that stores materials in the cell

Store: water, salts, proteins and carbohydrates

Question 9

Lysosomes Role

Answer 9

AKA “cleanup crew”
Smaller organelles that contain digestive enzymes that break down macromolecules: lipids (fats), carbohydrates, and proteins into smaller molecules that can be easily used by the cell

Question 10

Smooth ER (endoplasmic reticulum) Role

Answer 10

-NOT involved in making proteins (and therefore DOES NOT have ribosomes attached to its surface).
-Involved in making lipid components for cell membrane.

Question 11

Cytoskeleton Role

Answer 11

Helps the cell maintain its shape and allows for movement. (Similar to a beam that holds up a roof in a house)

Question 12

Ribosome Role

Answer 12

Once RNA transfers into the ribosomes, they make proteins based on DNA’s instructions.

Question 13

Rough ER (endoplasmic reticulum) Role

Answer 13

• Where proteins are made (has ribosomes attached to it).
• These proteins then go trough the Rough ER to be further made (chemically modified).

Question 14

Golgi Apparatus Role

Answer 14

Organelle that modifies, sorts, and packages proteins and other materials from the ER .
Proteins are brought in a vesicle from the rough ER.
Golgi adds the “final touches” to these proteins.

Question 15

Transport Vesicle Role

Answer 15

-Move molecules between organelles.
Specifically: They ships the vesicles from Golgi in their final destination, in, or out of the cell.

Question 16

Chloroplast Function

Answer 16

PLANT ONLY
Captures the energy from the sunlight and converts it into glucose (food )
(AKA: photosynthesis!)

Question 17

Mitochondria Function

Answer 17

Known as the “powerhouse of the cell”
Converts chemical energy stored in food into energy that is more convenient for the cell to use (ATP) - where cellular respiration happens!

Question 18

Cell Membrane Function

Answer 18

Regulates what enters and leaves the cell, protecting and supporting it.

Question 19

Cell Wall + Cell Membrane Comparison

Answer 19

Cell wall - rigid, organized (only plant)
Cell membrane - flexible (both)

Question 20

Protein Production

Answer 20

• Nucleus - protein synthesis begins, DNA → RNA
• Ribosome - make proteins
  -Rough ER - proteins that go through are chemically modified
  -Golgi apparatus - to proteins are brought by the Rough ER for it to add “final touches” to them.
  -Transport vescicle - spread protein

Question 21

Energy Production

Answer 21

-Mitochondria - chemical energy in food to ATP (energy more convienent to cell)
-Chloroplast - captures energy in sunlight converts to glucose

Question 22

Cell Barriers

Answer 22

-Cell membrane
-Cell wall

Question 23

Cell Structure

Answer 23

-Cytoskeleton

Question 24

Storage

Answer 24

-Storage vesicles
-Central vacuole
-Lysosomes

Question 25

Magnification

Answer 25

Ocular lens x objective lens. Ocular lens = 10x. Examples= 4x= 40x, 10x=100x, 40x =400x

Question 26

Microscope Low and High Power Benefits

Answer 26

• high power is used after low power for more magnification
• low power is used to locate specimen

Question 27

Difference Between Coarse and Fine Focus

Answer 27

Coarse focus - used under low power objective
fine focus - sharpens the image

Question 28

Cell Membrane Components

Answer 28

Glycoproteins
- Serve as signals to other cells so that they can “recognize” each other
- Made of protein AND carbs

Proteins
- Let substances in/out of cell
- Take signals from outside of cell and communicate to inside of cell

Cholesterol
- Allows he “tails” of the lipids to maintain an orderly form in the membrane

Question 29

Passive Transport

Answer 29

Passive Transport: Substances move from high to low concentrations (no energy required) until they reach equilibrium (same concentration on both sides of cell)

Types of passive transport:
Diffusion - Movement of a substance across the membrane without the help of proteins.
Types of substances:
- Smaller molecules
- nonpolar molecules
- H20

Osmosis - The diffusion of water across a membrane (lots of H20 to little H20)

Facilitated Diffusion - Diffusion with the help of transport proteins
Types of substances:
- polar molecules
- Ions
- larger molecules

Question 30

Active Transport

Answer 30

Active Transport: Substances are moving from a low to high concentration (energy in the form of ATP is required to create the transport proteins/protein pumps that move the particles)

Endocytosis - The cell membrane forms a vesicle or vacuole within the cytoplasm to take larger material INto the cell

Exocytosis - Membranes of the vesicles fusing with the cell membrane to take large molecules/quantities OUT of the cell.

Question 31

Hypertonic, Hypotonic, and Isotonic

Answer 31

Hypertonic - the solution has a higher concentration of solute than the cell - causing water to move out of the cell (cell and vacuole shrink).

Hypotonic - The solution has a lower concentration of solute than the cell - water moves into the cell (cell and vacuole swell).

Isotonic - the solution and the cell have the same concentration of solute- water moves in and out (no change in animal cell or vacuole shape).