2.1.1 Basic Components of Living Systems Flashcards Preview

A Level Biology > 2.1.1 Basic Components of Living Systems > Flashcards

Flashcards in 2.1.1 Basic Components of Living Systems Deck (34)
Loading flashcards...
1
Q

Cell theory states that:

A
  • both plant and animal tissue composed of cells
  • cells are the basic unit of all life
  • cells only develop from existing cells
2
Q

Compound light microscope

A

Mag = 2000X

Res = 200nm

Objective and eyepiece lenses
Dead/alive specimens
Inexpensive

Can’t see ultrastructure of cell

3
Q

Why is staining used?

A

To observe specific organelles

To differentiate between different types of cell

To distinguish between diff tissues

4
Q

Positive staining

A

e.g. methylene blue

+ve charged stain attracted to -ve components

5
Q

Negative staining

A

e.g. nigrosin

Contrast between anything and water

6
Q

Units of measurement

A

mm ➗ 1000 = micrometer

micrometer ➗ 1000 = nanometer

7
Q

definition of MAGNIFICATION

A

How many times larger the image is than the actual size of the object viewed

8
Q

Calculating magnification

A

Mag=image➗actual

I
A M

9
Q

definition of RESOLUTION

A

The ability to distinguish individual objects as separate entities

10
Q

TEM

A
Mag = 500,000X
Res = 0.5 nm

Beam of electrons
Travel through specimen
Create a b&w 2D image
Ultrastructure can be seen

11
Q

SEM

A
Mag = 100,000X
Res = 3-10 nm

Beam of electrons
Across surface of specimen
Reflected atoms collected
3D images of surface

12
Q

Laser scanning confocal microscope

A

Res = higher than light

Single spot of focused light across specimen (point illumination)
Causes fluorescence from components labelled w dye
2D image

13
Q

Light vs Electron

A

Light =
inexpensive,portable,simple prep, natural colour,X2000 mag,living and dead,200nm res

Electron =
expensive,large,complex sample prep,b&w images,X500,000 mag,dead specimens only,0.5/3-10nm res

14
Q

Light mag/res

A

Mag X2000

Res 200nm

15
Q

TEM mag/res

A

Mag X500,000

Res 0.5nm

16
Q

SEM mag/res

A

Mag X100,000

Res 3-10mm

17
Q

Nucleus

A
DNA
Synthesis of proteins 
Nuclear envelope=double membrane
Nuclear pores
Chromatin coils into chromasomes
18
Q

Nucleolus

A

In nucleus

Produces ribosomes

19
Q

Mitochondria

A

Sire of final stages of cellular respiration
Energy stored in bonds
Production of ATP
Double membrane

20
Q

Vesicles

A

Sacs for storage and transport

Transport materials inside the cell

21
Q

Centrioles

A

Made of microtubules, two form centrosome

Flagella and cilia

22
Q

Endoplasmic reticulum

A

Network of membranes with flattened sacs / cisternae

23
Q

Rough ER

A

Ribosomes on surface

Synthesis and transport of proteins

24
Q

Smooth ER

A

Lipid and carbohydrate synthesis

Storage

25
Q

Ribosomes

A

Made of RNA
Made in nucleolus
Site of protein synthesis

26
Q

Golgi apparatus

A

Cisternae
No ribosomes

Modify proteins
Packages proteins into vesicles

27
Q

Protein production

A

i) synthesised on ribosomes on ER
ii) pass into cisternae, packaged into transport vesicles
iii) move to golgi via cytoskeleton
iv) vesicle fuses w cis face of golgi, proteins enter. Proteins modified then leave on trans face
v) secretory vesicles carry to surface membrane = exocytosis

28
Q

Cellulose cell wall

A
Plants 
Carbohydrate 
Freely permeable
Shape 
Defence mechanism
29
Q

Vacuoles

A
Plants 
Contain cell sap
Maintain turgor 
Membrane=tonoplast
Selectively permeable
30
Q

Chloroplasts

A
Plants 
Photosynthesis 
Green
Double membrane 
Fluid=stroma 
Internal membranes=thylakoids
Several thylakoids=granum 
Grana joined to membrane called lamellae
31
Q

Lysosomes

A

Specialised vesicles
Hydrolytic enzymes
Break down waste material
Immune system

32
Q

Cytoskeleton

A

i) microfilaments
Actin, contractile, cell movement/contraction

ii) microtubules
Globular tubulin, proteins, shape, tracts for movement

iii) intermediate fibres
Strength, shape

33
Q

Prokaryotes

A
No nucleus 
Circular DNA
Non-membrane-bound organelles
Peptidoglycan cell wall
70s smaller ribosomes
Reproduce: binery fission
Unicellular
34
Q

Eukaryotes

A
Nucleus 
Linear DNA
Membrane-bound organelles
Chitin cell wall (fungi)
Cellulose cell wall (plants)
80s larger ribosomes 
Reproduce: asexual/sexual
Uni/multicellular