2.1.1 Cell Structure COMPLETE

Question 1

Characteristics of living things

Answer 1

Movement
Respiration
Sensitivity

Growth
Reproduction 
Excretion 
Nutrition
Homeostasis

Question 2

Cell Ultrastructure

Answer 2

The detail revealed by the electron microscope. The structures inside are called organelles

Question 3

Division of Labour

Answer 3

Each organelle has a specific role with in the cell, they work together in the cell for survival

Question 4

How the light microscope works

Answer 4

Light reflects from the lamp so it passes through the condenser and focusses
It then goes through the stage and travels up the lens until it reaches the eyepiece
This can be adjusted to focus it

Question 5

Stains

Answer 5

Coloured chemicals that bind to molecules in a specimen
e.g. iodine solution can be used for live plant cells
Eosin goes pink to show cytoplasm

Question 6

Magnification

Answer 6

The number of times larger an image is compared to the actual size of the object
=Image/Actual

Question 7

Resolution

Answer 7

Ability to distinguish between two separate points that are very close together, gives clarity

Question 8

Max. resolution for Light and Electron microscopes

Answer 8

Light: 200nm
Electron: 0.1nm

Question 9

Unit changes

Answer 9

1m = 1000mm
1mm = 1000um 
1um = 1000nm

Question 10

Laser Scanning Microscopes

Answer 10

A laser is projected onto a pinpoint target in a specimen
Specimens are tagged with fluorescent dyes
Target area is scanned rapidly to produce a 3D image at different focal planes

Question 11

Use of Scanning Microscopes

Answer 11

• Developing drugs as isn’t invasive and you can see living cells
• Can see specific parts of the cell
• Can look at the whole cell

Question 12

Electron Microscopes

Answer 12

Takes place in a vacuum so electrons aren’t disrupted, specimen must be dead as coated in gold to attract electrons
Transmission so passes through surface producing a 2D B&W image

Question 13

Nucleus

Answer 13

Has a nuclear envelope with pores
The nucleoplasm contains chromatin
The outermsmbrane is continuous with the rough ER
Function:Enclose DNA, manufactures Ribosomes, cell division

Question 14

Endoplasmic Reticulum

Answer 14

A system of hollow tubes and sacs
Rough is covered in ribosomes for protein synthesis which can then be transported
Smooth lacks ribosomes and synthesises lipids

Question 15

Ribosome

Answer 15

2 protein subunits of rRNA
Synthesised in the nucleus
Function: Protein synthesis, provides binding sites for mRNA, contains enzymes
2 types for eukaryotes and prokaryotes (smaller)

Question 16

Golgi apparatus

Answer 16

Flattened membrane with bound cavities called cisternae stacked on top of each other
Function: Modifies carbohydrates, packages proteins into vesicles

Question 17

Lysosomes

Answer 17

Vesicles containing hydrolytic enzymes
Function: Isolate potentially harmful enzymes from cels, breakdown material ingested by phagocytic cells, breakdown old organelles

Question 18

Mitochondria

Answer 18

Double membrane, the inner folds in to form cristae
The inner matrix contains ribosomes, DNA and enzymes
Function: Isolates aerobic reactions to produce ATP

Question 19

Chloroplast

Answer 19

Double membrane with membrane bound sacs called thylakoids inside. They stack to form grana and are connected by lamellae. Stroma contains enzymes, starch grains, ribosomes, DNA, lipid droplets
Function: Photosynthesis

Question 20

Centrioles

Answer 20

Found in pairs and are composed of 9 sets of three tubules. 2 sets are found in every animal cell
Function: Forms spindle fibres for nuclear division

Question 21

Cytoskeleton

Answer 21

Composed of microtubules and microfilaments
Function: Enable movement of vesicles, proteins, organelles
Also help support the cell and maintain shape

Question 22

Flagella and Cilia

Answer 22

Composed of two central microtubules and surrounded by nine more
The sliding of the microtubule leads to movement with ATP, found in respiratory tract and oviduct

Question 23

Vacuoles

Answer 23

Contain cell sap (water, sugar, oil, protein, pigment)
Have a special membrane called a tonoplast
They maintain turgor for support and also store things

Question 24

Plant cell walls

Answer 24

Rigid and permeable for protection

Made of cellulose and modified by lignin, prevents osmotic bursting

Question 25

Process: Division of Labour

Answer 25

1. Nucleus- mRNA copy instructions
2. mRNA leaves the nucleus through pores
3. mRNA attaches to ribosome to read how to make protein
4. Insulin molecules are pinched off in vesicles to travel towards the golgi
5. Vesicle fuses with the Golgi
6. Golgi processes and packages the insulin
7. Packages insulin pinched off and moves towards the surface membrane
8. Vesicle fuses with the surface membrane

Question 26

Prokaryote features

Answer 26

Always: Circular DNA, Plasma membrane, Cytoplasm where anaerobic respiration, ribosomes, cell wall
Additional: Pilli, plasmid, capsule, mesosome, Flagellum