Cells

Question 1

Robert Hooke’s contribution the the cell theory.

Answer 1

Robert Hooke observed cork under a microscope and saw box-like structures. He named them cells.

Question 2

Anton Van Leeuwenhoek’s contribution the the cell theory.

Answer 2

Anton Van Leeuwenhoek observed his own blood and sperm, as well as pond water.

Question 3

Robert Brown’s contribution the the cell theory.

Answer 3

Robert Brown observed the nucleus. He believed all cells had one.

Question 4

Matthias Schleiden’s contribution the the cell theory.

Answer 4

Matthias Schleiden proposed that all plants were made of cells.

Question 5

Theodor Schwann’s contribution the the cell theory.

Answer 5

Theodor Schwann proposed that all animals were made of cells, then that all living things were.

Question 6

Rudolph Virchow’s contribution the the cell theory.

Answer 6

He gathered enough info to develop a proper cell theory.

Question 7

List four points of the cell theory.

Answer 7

• All living things are composed of one or more cells.
• Cells are the basic unit of structure and function in all organisms.
• All cells arise from previously existing cells.
• The activity of an entire organism depends on the total activity of individual cells.

Question 8

How are prokaryotic cells more primitive than eukaryotic cells? (3)

Answer 8

• Smaller
• No organelles
• No nucleus (DNA is in a single chromosome)

Question 9

Describe the nucleus. (6)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 9

• Eukaryotic only
• Usually the largest organelle
• Contains the cell’s DNA
• Contains instructions for making a cell work
• Contains one or more nucleolus (pl. nucleoli)
• Surrounded by a double-layered nuclear membrane

Question 10

What do the nucleoli within a nucleus do? (1)

Answer 10

• Produce ribosomes which assemble protein

Question 11

What are three reasons why cells have a limit to how big they can grow?

Answer 11

1. As cells get bigger, they need more stuff and produce more waste.
2. Cell membranes are weak and will eventually burst.
3. Cells need to send messages within themselves. Eventually, messaging will not be efficient.

Question 12

Define / describe the cell membrane. (2)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 12

• Eukaryotic and Prokaryotic cells.
• Encloses the entire cell and regulates what goes in and out.

Question 13

Define / describe the cytosol. (2)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 13

• Eukaryotic and Prokaryotic cells.
• Jelly-like material between cell membrane and nuclear membrane.
• Contains necessary materials for cell function.

Question 14

Describe the cytoplasm. (1)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 14

Cytoplasm includes the cytosol and all organelles within.

Question 15

Define / describe the mitochondria. (5)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 15

• Eukaryotic only.
• Roundish organelles surrounded by two membranes with the inner one being folded.
• Produces energy for the cell and entire organism
• Mitochondria have their own DNA and can replicate themselves
• Were once independent bacteria

Question 16

Define / describe the endoplasmic reticulum. (2)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 16

• Network of membrane enclosed, fluid filled tunnels that form a continuous network through the cell.
• Provides transportation paths through the cell.

Question 17

What is the difference between rough and smooth endoplasmic reticulum? (3)

Answer 17

• Smooth endoplasmic reticulum produce fat
• Rough endoplasmic reticulum produce protein
• Rough endoplasmic reticulum have ribosomes on the surface

Question 18

Define / describe the golgi body. (4)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 18

• Eukaryotic only
• Stacks of flattened membrane sacs
• Processing, packaging, and storing centres for cell products
• Works closely with the E.R.

Question 19

Define / describe vacuoles. (4)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 19

• Eukaryotic and prokaryotic
• Fluid filled membrane bubbles
• Store food, water, waste, etc.
• Tend to be larger in plants

Question 20

Define / describe the cell wall. (5)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 20

• Eukaryotic and prokaryotic
• Not in animal cells
• Thick, rigid walls outside of cell membranes
• Supports cell and entire plant
• Consists of different material for different organisms (For plants, it is cellulose)

Question 21

Define / describe lysosomes. (4)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 21

• Eukaryotic only
• Small vacuole-like structures
• Contains powerful digestive enzymes
• Breaks down things (large food bits, worn-out organelles, or unwanted visitors like bacteria)

Question 22

Define / describe chloroplasts. (6)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 22

• Eukaryotic only
• Only in plants and algae (photosynthic protists)
• Surrounded by two membranes
• Contains chlorophyll (pigment that makes plants green)
• Where photosynthesis takes
• Similar to mitochondria, it clones itself

Question 23

What is photosynthesis? (2)

Answer 23

• A process used by plans to make their own food
• Carbon dioxide + ENERGY = SUGAR

Question 24

Define / describe centrioles. (4)
* What cell is it found in?
* what does it look like?
* What is its purpose?

Answer 24

• Eukaryotic only
• Only animal cells and similar protists
• Paired cylindrical structures
• Function in cell division

Question 25

List differences between plant and animal cells.

Answer 25

Plants: Cell wall, chloroplasts, no centrioles, rarer lysosomes, larger vacuoles Animals: No cell wall, no chloroplasts, centrioles, common lysosomes, smaller vacuoles

Question 26

Describe interphase. (3)

Answer 26

* Resting stage, growing and doing regular job * Chromatin (DNA) duplicates * Centrioles duplicate

Question 27

Describe prophase. (3)

Answer 27

* Chromatin winds up and forms double-stranded chromosomes * Centrioles move to opposite ends, casting spindle fibres * Nuclear membrane and nucleolus disappears

Question 28

Describe metaphase. (2)

Answer 28

* The centromere of chromosomes attach to a spindle fibre * The spindle fibres line up chromosomes on the equator

Question 29

Describe anaphase. (3)

Answer 29

* The centromere of each chromosome splits * Chromatids ate now single-stranded chromosomes * Each chromosome is pulled to a pole of the cell

Question 30

Describe telophase. (5)

Answer 30

* Chromosomes are on opposite ends of the cell * Chromosomes unwind to become chromatin * Nuclear membrane forms in each new nucleus * Nucleoli forms in each new nucleus * Spindle fibres disappear

Question 31

Describe cytokinesis. (3)

Answer 31

* The division of the cytoplasm * Cell membrane moves inward at two points until the cell is pinched in two * Two genetically identical cells have been made

Question 32

List differences in plant and animal cell division. (2)

Answer 32

* Plant cells do not have centrioles but spindle fibres still appear somehow * Cell walls are too rigid to pinch; a cell wall forms between the new nuclei instead