Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AQA Biology A level > Cells > Flashcards

Cells Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Nucleus structure

A

Usually spherical with diameter of between 10 and 20µm

Nuclear envelope

Nuclear pores

Nucleoplasm

Chromosomes

Nucleolus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Nuclear envelope

A

Double membrane that surrounds nucleus

Outer membrane is continuous with the E.R. and often has ribosomes on its surface

Controls the entry and exit of materials and controls the reactions taking place within

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Nuclear pores

A

40-100nm in diameter

Around 3000 pores in each nucleus

Allow the passage of large molecules, such as messenger RNA out of the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Nucleoplasm

A

Granular jelly-like material that makes up the bulk of the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Chromosomes (nucleus)

A

Consist of protein-bound linear DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Nucleolus

A

Small spherical region within the nucleoplasm

Manufactures ribosomal RNA and assembles proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Nucleus function

A

Controls the cell’s activities

Produces mRNA and tRNA

Retain genetic material as DNA and chromosomes

Manufactures ribosomal RNA and ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Mitochondrion structure

A

Rod shaped

1-10µm in length

Has a double membrane that controls the entry and exit of materials

Cristae

Matrix

High in cells that have a high level of metabolic activity

Abundant in muscle and epithelial cells for aerobic respiration and active transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cristae

A

Extensions of the inner membrane

Provide a large surface area for the attachment of enzymes and other proteins involved in respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Matrix

A

Contains proteins, lipids, ribosomes and DNA

Can control the production of some of their own proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Mitochondrion function

A

Site for the aerobic stages of respiration

  • The krebs cycle

-Oxidative phosphorylation pathway

Responsible for the production of ATP energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Endoplasmic reticulum structure

A

Elaborate three dimensional system of sheet-like membranes

Spread through cytoplasm and outer membrane

Network of tubules and flattened sacs called cisternae enclosed in the membrane

Abundant in liver and secretory cells, e.g. epithelial cells have very extensive E.R.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Rough endoplasmic reticulum (RER)

A

Ribosomes present on the outer surface

Large surface area present for the synthesis of proteins and glycoproteins

Provides a pathway for transport of materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Smooth endoplasmic reticulum (SER)

A

Lacks ribosome

More tubular appearance

Synthesise, store and transport lipids

Synthesise, store and transport carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Difference between the RER and SER

A

RER has ribosomes present of surface

SER lacks ribosomes

SER is more tubular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ribosome structure

A

Small cytoplasmic granules

2 sub units - one small, one large

80s and 70s

Contain ribosomal RNA and a protein

Accounts for up to 25% of the dry mass of a cell

May occur in the cytoplasm or be associated with the RER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

80s ribosome

A

Found in eukaryotic cells

25nm in diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

70s ribosome

A

Found in prokaryotic cells, mitochondria and chloroplasts

Slightly smaller than 80s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Ribosome function

A

Site for proteinsynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Golgi apparatus structure

A

Similar structure to the SER but more compact

Stack of membranes that make up cisternae with vesicles

Abundant in secretory cells such as epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Golgi apparatus function

A

Adds carbohydrate to proteins to form glycoproteins and ‘labels’ them

Produce secretory enzymes

Secretes carbohydrates

Transport, modify and store lipids in golgi vesicles

Passes proteins and lipids formed by the ER through a strict sequence

Form lysosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Lysosome structure

A

Up to 1µm in diameter

As many as 50 enzymes can be contained in one lysosome

Contain enzymes such as proteases and lipases and lysozymes

Abundant in secretory cells such as epithelial cells and phagocytic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Lysosome function

A

Hydrolyse material ingested by phagocytic cells

Release enzymes to the outside of the cell (exocytosis) or into a phagocytic vesicle in order to destroy material around the cell

Digest worn out organelles so useful chemicals can be reused

Completely break down cells after they have died (autolysis)

24
Q

Chloroplast structure

A

Disk-shaped

2-10 mm long and 1 mm in diameter

Chloroplast envelope

Grana

Stroma

Contains both DNA and ribosomes so they can quickly and easily manufacture proteins for photosynthesis

25
Q

The chloroplast envelope

A

Double plasma membrane

Highly selective

26
Q

Grana

A

Stacks of up to 100 disk-like structures called thylakoids

Chlorophyll is found in thylakoids

Some thylakoids have tubular extensions that join up with thylakoids in adjacent grana

Where the first stage of photosynthesis occurs (light absorption)

Granal membranes provide a large surface area for the attachment of chlorophyll, electron carriers and enzymes

27
Q

Stroma

A

Fluid filled matrix

Where the second stage of photosynthesis occurs (synthesis of sugars)

Possesses all of the enzymes needed to make sugars

28
Q

Chloroplast function

A

Carry out photosynthesis

29
Q

Cell wall structure

A

Consist of microfibrils of cellulose, embedded in a matrix

Consist of a number of polysaccharides such as cellulose

Thin layer present called the middle lamella which marks the boundary between adjacent cell walls and cements adjacent cells together

30
Q

Cell wall function

A

To provide mechanical strength to prevent cell from bursting due to pressure from osmosis

To give mechanical strength to the plant as a whole

To allow water to pass along it and contribute to the movement of water through the plant

31
Q

Cell wall in algae

A

Made of cellulose and/or glycoproteins

32
Q

Cell wall in fungi

A

Dont contain cellulose but a mixture of a polysaccharide called chitin, glycan and glycoproteins

33
Q

Vacuole structure

A

Fluid filled sac

Bound by a single membrane called the tonoplast

Sac contains mineral salts, sugars, amino acids and pigments such as anthocyanins

34
Q

Vacuole function

A

Supports herbaceous/herbaceous parts of woody plants

Makes cells turgid

The pigments attract pollinating insects

Sugars and amino acids act as temporary food sources

35
Q

Are animals multicellular or unicellular?

A

Multicellular

36
Q

Are plants multicellular or unicellular?

A

Both

37
Q

Are fungi multicellular or unicellular?

A

Both
(e.g. yeast is unicellular)

38
Q

Are protists multicellular or unicellular?

A

Unicellular

39
Q

What are the 3 domains?

A

Eukarya

Bacteria

Archaea

40
Q

Eukarya (structure)

A

Membrane bound organelles

Membrances contain fatty acid chains attached to glycerol via ester bonds

Some have cell walls

All have 80s ribosomes

41
Q

Bacteria (structure)

A

No membrane-bound organelles

Generally unicellular, but xan be clusters

70s ribosomes

Cell walls made of murein, not chitin or cellulose

42
Q

Archaea (structure)

A

Originally classed as bacteria but they are more complex

Membrances similar to eukarya

Complex form of RNA polymerase

Some have cell walls

43
Q

Prokaryotic cell structure

A

No nucleus

Circular, free flowing DNA

No membrane bound organelles

Smaller cells

70s ribosomes

Plasmids

Flagella

44
Q

Eukaryotic cell structure

A

Distinct nucleus

Nuclear envelope

Double membrane bound organelles

Larger cells

80s ribosomes

RER

SER

45
Q

Life cycle of a virus

A
  1. Binding
    - Attachment protein binds onto complementary receptor on the cell
  2. Fusion
    - Lipid envelope/cell membrane fuse together, releasing capsid into cytoplasm
  3. Reverse transcription
    - RNA is converted into DNA
  4. Intergration
    - Viral DNA inserted into host DNA
  5. Replication
    - Use DNA to make parts of virus DNA
  6. Assembly
    - Viruses are assembled
  7. Budding
    - Virus leaves cell and binds onto another receptor and spreads
46
Q

Every virus has

A

Genetic material

Capsid

Attachment protein (for movement)

47
Q

Some viruses have

A

Lipid envelope

48
Q

Membrane structure

A

Flexible

Mainly made of phospholipids

49
Q

Membrane function

A

Allow cellular compartments to have different conditions

50
Q

Phospholipid bi-layer structure

A

Hydrophyllic head:

Phosphate group

Phosphoester bond

Hydrophobic tail:

Glycerol

Ester bond

Fatty acid

O O O O O
|| || || || ||Hydophobic tails facing
|| || || || ||away from water
O O O O O

51
Q

Phospholipid behaviour

A

Form micelles when submerged in water

Protein can move freely through the lipid bi-layer

52
Q

Cell fractionation

A

The process where cells are broken up and the different organelles they contain are separated out

53
Q

The two stages of cell fractionation

A

Homogenation

Ultracentrifugation

54
Q

Conditions before cell fractionation can begin

A

Tissue is placed in a cold buffered isoptopic solution

55
Q

Why does the solution have to be cold?

A

To reduce enzyme activity that might break down the organelles

56
Q

Why does the solution have to be buffered?

A

So the pH does not fluctuate

Any change in pH could alter the structure of the organelles or affect the functioning of enzymes

57
Q

Why does the solution have to be isotopic?

A

To prevent organelles from shrinking or bursting as a result of osmotic loss or gain of water

AQA Biology A level (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions