Cell Structure

Question 1

What are eukaryotic cells?

Answer 1

Complex and include all animal and plant cells
They have a membrane-bound nucleus

Question 2

What are prokaryotic cells?

Answer 2

Smaller and simpler than eukaryotic e.g bacteria
Lacks a nucleus and other membrane bound organelles

Question 3

What is the nucleus?

Answer 3

Contains chromosomes (wound up DNA) in a nuclear envelope (double membrane) and controls cells activity.
It contains the nucleolus where ribosomes are made

Question 4

What is the cell surface membrane?

Answer 4

Made up from lipids and proteins and controls the movement of substances in and out the cell

Question 5

What is mitochondria?

Answer 5

Mitochondria have a double membrane where the inner one is folded into cristae.
It contains enzymes involved in respiration and production of ATP
It is the site of aerobic respiration

Question 6

What are ribosomes?

Answer 6

Very small organelles attached to the rough ER or free in the cytoplasm
Where proteins are made

Question 7

What is the Golgi apparatus?

Answer 7

A fluid filled membrane that produces new lipids and proteins

Question 8

What is a Golgi vesicle?

Answer 8

Buds off the Golgi apparatus and stores and transports lipids and proteins

Question 9

What are chloroplasts?

Answer 9

The location of a photosynthesis only found in plant and algal cells
Double membrane where the inside membrane is called the thylakoid membrane
Chloroplasts contain chlorophyll which absorbs light for photosynthesis

Question 10

What is the RER?

Answer 10

It is covered in ribosomes
It processes proteins made in the ribosomes

Question 11

What is the SER?

Answer 11

Site of synthesis and processing of lipids

Question 12

What is a lysosome?

Answer 12

Contains digestive enzymes and keeps them separate from the cytoplasm

Question 13

What is cytoplasm?

Answer 13

Where most reactions take place in a cell

Question 14

What is the cell wall?

Answer 14

Ensures cell structure is maintained. Animal cells do not have a cell wall.

Question 15

What is a vacuole?

Answer 15

Contains sap
Helps maintain pressure inside cell and keeps them rigid

Question 16

What are examples of ways cells maximise diffusion?

Answer 16

Microvilli to increase SA in ileum epithelium
Biconcave shape in RBCs to increase SA

Question 17

What are examples of ways cells are adapted for storage?

Answer 17

Fat cells can have large lipid stores
RBC have no nucleus to increase haemoglobin storage space and bind to more oxygen

Question 18

How are cells adapted for secretion?

Answer 18

Large Golgi to produce many vesicles
Large RER or many ribosomes to produce proteins e.g goblet cells which secrete mucus

Question 19

How are cells adapted for increased energy requirements?

Answer 19

Lots of ATP so contain many mitochondria to carry out more respiration e.g muscle cells which contract and nerve cells

Question 20

How are cells adapted for transport?

Answer 20

Lots of carrier proteins and channel proteins on their cell surface membrane
Increased ribosomes to produce a large amount of proteins

Question 21

What ribosomes do prokaryotes have?

Answer 21

Ribosomes 70, smaller than eukaryotic ribosomes

Question 22

What does a prokaryotic cell wall contain?

Answer 22

Glycoprotein murein

Question 23

What is flagella?

Answer 23

Long structure that rotates to propel the cell (motility)

Question 24

How is DNA contained in a prokaryotic cell?

Answer 24

In the cytoplasm in one long coiled strand
Plasmids
Which are small sections of DNA easily passed between bacteria helping the spread of genes e.g antibiotic resistance

Question 25

What are capsules?

Answer 25

Prokaryotic cells might have capsules of secreted slime to protect the cell from attack

Question 26

How many micrometers are in a millimetre?

Answer 26

1000 micrometers in 1mm

Question 27

How many manometers are in a micrometer?

Answer 27

1000nm in 1 micrometre

Question 28

What does resolution mean?

Answer 28

How well a microscope distinguishes between two points that are close together

Question 29

What is a light microscope?

Answer 29

Uses light to form an image Can see objects larger than 0.2 micrometers Colour Live Max magnification of around x1500

Question 30

What is an electron microscope?

Answer 30

Very large Computer generated Use electrons to form an image Can see much smaller objects More detailed at higher resolution Black and white Dead/fixed Max magnification around x1,500,000

Question 31

What are the two types of electron microscope

Answer 31

Transmission electron microscope (TEM) Scanning electron microscope (SEM)

Question 32

What is a TEM?

Answer 32

Uses electromagnets to produce a beam of electrons Produces 2D images High resolution (0.0002micrometres) images for small organelles Need to be thinly sliced

Question 33

What is SEM?

Answer 33

Beam electrons across the specimen Produces the surface of the specimen Can be 3D Give lower resolution (0.002micrometres) than TEM

Question 34

What is the equation for magnification?

Answer 34

Size of image divided by actual size (I/AM)

Question 35

What is the cytoskeleton?

Answer 35

Protein threads running through the cytoplasm called microfilaments and microtubules It is dynamic which allows it to respond to changes in the cell

Question 36

What are the functions of the cytoskeleton?

Answer 36

1) Supports cell organelles keeping them in position 2) Strengthen cell and maintain its shape 3) Transport of organelles and materials within the cell 4) Can cause the cell to move

Question 37

What does magnification mean?

Answer 37

How much bigger the image is than the specimen

Question 38

Why might abnormal mitochondria be problematic in heart tissue?

Answer 38

Heart tissue contains muscle cells which require lots of ATP for contraction Mitochondria are the site of aerobic respiration and therefore ATP production may be abnormal

Question 39

What type of ribosomes are in eukaryotic cells?

Answer 39

80s, bigger than prokaryotic