B1.1 - Cell structures

Question 1

What are Eukaryotic cells ? + Example

Answer 1

Cells whose genetic nuclei is contained within a nucleus.

e.g Animal cell, plant cell

Question 2

What are Prokaryotic cells ? + Example

Answer 2

Cells whose genetic material floats within the cytoplasms.

e.g bacteria

Question 3

Name all the organelles in an animal cell ?

Answer 3

• Nucleus
• Mitochndria
• Cytosplasm
• Cell membrane

Question 4

Name the organelles found in plant cells?

Answer 4

• Nucleus
• Cell wall
• Cell membrane
• Chloroplast
• Mitochondria
• Vacuole
• Cytoplasm

Question 5

what is the function of the nucleus ?

Answer 5

• Controls the cell, the activities in the cell
• Contains the organisms genetic material, arranged as chromosomes
• Determines cells appearance and function

Question 6

What is the function of the mitochondria ?

Answer 6

-The ‘power-house’ of the cell.
- Provides energy by respiration

Question 7

What is the function of the cell membrane?

Answer 7

• Holds the cell together
• Controls what goes in and out of the cell
• Delicate surface membrane made of two layers of phospholipid

Question 8

What is the cytoplasm ?

Answer 8

Jelly-like substance

Question 9

What is the function of the cytoplasm ?

Answer 9

• Transfers energy, makes things, and stores food.
• Jelly-like substance where hundreds of reactions take place, which make up metabolism/ keep the cell alive

Question 10

Difference between Eukaryotic and Prokaryotic cells?

Answer 10

Eukaryotic : The cell type is complex and relatively large 10-100 μm

Prokaryotic cells : The cell type is simple and typically smaller ~1-10 μm

Question 11

What does MRS GREN stand for ?

Answer 11

M = ovement

R = espiration

S = ensitivity

G = rowth

R = eproduction

E = xcretion

N = utrition

Question 12

Which English inventor and scientist where discovered cells using his self-designed microscope in 1665?

Answer 12

Robert Hooke

Question 13

Examples of Eukaryotic cells ?

Answer 13

Animal and plant cells

Question 14

Examples of Prokaryotic cells ?

Answer 14

Bacterial cells

Question 15

What are Ribosomes ?

Answer 15

Ribosomes are tiny granules on the membranes in the cytoplasm.

Question 16

What is the function of ribosomes ?

Answer 16

Ribosomes are where proteins are made in the cell

Question 17

What is the function of chloroplasts ?

Answer 17

• The chloroplasts contain green chlorophyll
• The chlorophyll transfers energy from the sun to the plant as light, which is used in photosynthesis.

Question 18

What do chloroplasts contain?

Answer 18

They contain green chlorophyll.

Question 19

What makes plants green ?

Answer 19

Chloroplasts, they contain green chlorophyll which makes the plant green.

Question 20

What is the function of the vacuole ?

Answer 20

• It is full of cell sap, a watery solution of sugar and salts
• It helps to keep the cell rigid, so supporting the plant and keeping it upright ( pushing outwards )

Question 21

What is the function of the cell wall ?

Answer 21

• This surrounds the cell.
• It is made of a tough fibre called cellulose
• It makes the wall rigid and supports the cell

Question 22

What are Bacteria ?

Answer 22

They are unicellular organisms ( made up of just one cell - prokaryotic )

Question 23

State three examples of commonly found bacteria ?

Answer 23

• Escherichia coli – Causes food poisoning
• Streptococcus – bacteria causes sore throats
• Streptomyces – bacteria found in soil and used to develop antibiotic streptomycin

Question 24

Name of primative bacteria-like organisms ?

Answer 24

Archaea

Question 25

What sub cellular structures do common prokaryotic cells contain ?

Answer 25

- Cell wall ( holds the cell together, protects it ) - Genetic material ( floats freely in the cytoplasm ) - Cell membrane ( A barrier that controls which substances enter/leave ) - Cytoplasm ( where chemical reactions happen )

Question 26

Describe the genetic material in prokaryotic cells commonly ?

Answer 26

There is one long strand of DNA called the bacterial chromosome. This is normal y circular

Question 27

List the structures and organelles you would expect to find in some bacteria cells ?

Answer 27

- Cell wall (peptigoglycan) - Cell membrane - Flagella - Single-loop DNA - Plasmids - Pili - Cytoplasm - Slime capsule

Question 28

What is the function of the flagella ?

Answer 28

Tail-like structures that allow bacteria cells to move through liquids

Question 29

What is the function of the Pili ?

Answer 29

- Tiny ‘hair-like’ structures that allow the cell to attach to structures, such a the cells in your digestive tract. - They are also used to transfer genetic material between bacteria cells.

Question 30

What is the function of the slime capsule ?

Answer 30

- Protects bacteria from drying out and from poisonous substances. - Helps bacteria to stick to smooth surfaces

Question 31

What is the function of the plasmid ?

Answer 31

- A circular piece of DNA found in bacteria cells - Not needed for day-to-day survival but can give the bacterium advantages such as antibiotic resistance

Question 32

Name the parts of a light microscope ?

Answer 32

- Body tube - Fine focussing knob - Mechanical stage - Stage - Objectives - Course focussing knob - Revolving nosepiece - Eyepiece lens - Mirror - Arm - Base

Question 33

What is the equation for magnification?

Answer 33

Image size = Actual size x Total Magnification

Question 34

What is resolution ?

Answer 34

- The degree to which it is possible to distinguish between two objects that are very close together, rather than them look merged into one object. - The higher the resolution, the greater the detail you may see

Question 35

Name the two types of electron microscopes ?

Answer 35

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

Question 36

What are TEM used for and how have they advanced science?

Answer 36

- TEM is used to examine an extremely thin slice or section of cells or tissues - TEM has revealed subcellular structures in cells not visible with a light microscope such as mitochondria and chloroplasts

Question 37

What are SEM used for and how have they advanced science?

Answer 37

- They produce a 3-D image of a surface by bouncing a beam of electrons off of a specimen.

Question 38

What are the advantages and disadvantages of light microscope and electron microscopes?

Answer 38

Light microscope : - Cheep to buy and operate - Small and portable - Simple to prepare sample - Natural colour of sample is seen unless staining is used. - Specimens living or dead - Resolution up to 0.2 µm (2 x 10-7 m) Electron Microscope : - Expensive to buy and operate - Large and difficult to move - Sample preparation is complex - Black and white images produced; false colour can be added to images - Specimens are dead - Resolution up to 0.1 nm (1 x 10-10 m)

Question 39

Why are cells stained ?

Answer 39

So that they are easier to observe, it also highlights specific sub-cellular structures

Question 40

What are the three common stains ?

Answer 40

- Methylene blue - makes It easier to see the nucleus of an animal cell - Iodine - This makes it easier to see the plant cell - Crystal violet - this stains bacterial cell walls

Question 41

Method for staining cells ?

Answer 41

- Pace the cells on a glass slide - Add one drop of stain - Place a coverslip on top - Tap the coverslip gently with a pencil to remove air bubbles

Question 42

How do light microscopes work ?

Answer 42

- The microscope passes light through the object on the stage, then through two glass lenses ( the objective lens and the eyepiece ) - The lenses magnify the object so when you look at it you see more detail