Cell Structure

Question 1

Give 3 benefits of using optical microscopes

Answer 1

• Relatively cheap
• Easy to use
• Portable

Question 2

State 2 benefits of laser scanning microscopes

Answer 2

• Produce high resolution/high contrast images

Question 3

Do electron microscopes have good resolutions?

Answer 3

Yes

Question 4

Which type of electron microscope has a larger magnification?

Answer 4

Transmission; x2 million
Scanning; x15 –> x200,000

Question 5

Give one similarity between the images produced by transmission and scanning electron microscopes

Answer 5

• Both produce black and white images

Question 6

Which type of microscope produces a 3D image?

Answer 6

Scanning electron microscopes

Question 7

Which type of microscope requires the specimen to be chemically fixed before viewing?

Answer 7

Transmission electron microscopes

Question 8

What is the function of the nuclear envelope?

Answer 8

Separates the nucleus from the rest of the cell

Question 9

What does the nucleolus contain?

Answer 9

RNA

Question 10

What is made in the nucleolus?

Answer 10

Ribosomes

Question 11

Name the chemical which makes up genetic material

Answer 11

Chromatin

Question 12

Where is chromatin found in a cell?

Answer 12

Nucleus

Question 13

What is the main function of the nucleus?

Answer 13

To control the activities of the cell

Question 14

Describe the structure of the rough endoplasmic reticulum

Answer 14

• System of membranes, covered in ribosomes

Question 15

What is the role of rough endoplasmic reticulum?

Answer 15

To process and packaging proteins

Question 16

Why is the rough endoplasmic reticulum coated in ribosomes?

Answer 16

To assemble amino acids into protein

Question 17

Why does the smooth endoplasmic reticulum contain enzymes?

Answer 17

To catalyse reactions

Question 18

Give some examples of reactions that take place in the smooth endoplasmic reticulum

Answer 18

• Synthesis of steroid hormones
• Synthesis of cholesterol
• Synthesis of lipids

Question 19

Describe the structure of the Golgi apparatus

Answer 19

A stack of membrane bound flattened sacs

Question 20

What is the role of the Golgi apparatus?

Answer 20

Protein modification

Question 21

What is the function of the mitochondria?

Answer 21

• Site of ATP production
• Aerobic respiration

Question 22

How are mitochondria structured?

Answer 22

Fluid-filled matrix

Question 23

What reaction occurs in chloroplasts?

Answer 23

Photosynthesis

Question 24

How are chloroplasts structured?

Answer 24

• Surrounded by double membrane
• Inner membrane consists of thylakoid

Question 25

What role does a vacuole perform?

Answer 25

Helps support plant cells, filled with water and solutes

Question 26

What is the purpose of lysosomes?

Answer 26

- To digest large molecules and engulf foreign matter - Uses powerful hydrolytic enzymes

Question 27

Which 3 organelles aren't membrane-bound?

Answer 27

- Ribosomes - Cytoskeleton - Cell Wall

Question 28

What is the role of ribosomes?

Answer 28

To synthesise proteins

Question 29

What is the cytoskeleton?

Answer 29

A network of protein structures which support the cell and allow for movement within the cell

Question 30

How do cytoskeletal motor proteins work?

Answer 30

- They move things along microtubules - Energy from hydrolysis of ATP

Question 31

What is a cell wall made from?

Answer 31

Bundles of cellulose fibres

Question 32

What is the function of the cell wall?

Answer 32

- Prevent cells from bursting - Provide rigid structure to cell

Question 33

Describe the first step in making proteins

Answer 33

- Gene, with instructions for creating that specific protein, are transcribed onto mRNA

Question 34

What happens after a gene is transcribed onto mRNA, when making proteins?

Answer 34

mRNA is copied and passes through pores in nuclear envelope

Question 35

During the process of making proteins, what occurs after mRNA copies leave the nuclear envelope?

Answer 35

Instructions are translated and protein molecule is assembled at ribosomes

Question 36

How do protein molecules get to the Golgi apparatus from the rough endoplasmic reticulum?

Answer 36

- Molecules pass along cisternae - They enter vesicles and pass via microtubules and motor proteins to the Golgi apparatus

Question 37

How do vesicles release or extract protein molecules from the Golgi Apparatus?

Answer 37

By fusing or being pinched off the Golgi

Question 38

How are protein molecules released from vesicles to outside the cell?

Answer 38

Vesicles fuse with the plasma membrane and protein is released

Question 39

Name three sub-cellular structures that are common in eukaryotes and prokaryotes

Answer 39

- Ribosomes - Cytoplasm - Plasma membrane

Question 40

Do prokaryotes contain both DNA and RNA?

Answer 40

Yes

Question 41

Which type of cell is much smaller? Prokaryotes or Eukaryotes

Answer 41

Prokaryotes

Question 42

Give one difference between the cytoskeleton of eukaryotes and prokaryotes

Answer 42

Prokaryotes have less developed cytoskeletons

Question 43

Do prokaryotes have a nucleus?

Answer 43

NO - GCSE BIOLOGY

Question 44

What are prokaryotic cell's walls made of?

Answer 44

Peptidoglycan

Question 45

What type of organelles do prokaryotes not have?

Answer 45

Membrane-bound organelles

Question 46

State 3 features of prokaryotic cells

Answer 46

- Naked, free-floating plasmids - Flagella - Smaller ribosomes - Protective waxy capsule