Brainscape's Knowledge GenomeTM

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


See full index

Biology AS > Cells > Flashcards

Cells Flashcards

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

What is active transport?

A

Carrier proteins bind to molecule./ion to be transported
-molecule binds to receptor sites on carrier proteins
On inside of cell ATP binds to protein causing it to change shape to allow molecule into cell
ATP splits into ADP and phosphate
After molecule is released phosphate is released from proteins which means it reverts back to original shape

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

What is facilitated diffusion?

A

Facilitated diffusion is passive
Larger, water soluble molecules have to be taken across plasma membrane by carrier proteins or protein channels

Carrier proteins facilitate movement by physically binding molecules on one side of the membrane and releasing them on the other

protein channels allow ions through

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

Disadvantages of electron microscopes?

A
  • Complex preparation (staining)
  • Preparation kills living (Vacuum)
  • More likely image contains artefacts

TEM only

  • Specimen must be extremely thin
  • Image only in 2D
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Disadvantages of light microscopes?

A
  • Can only see certain objects

- resolution is limited by light wavelength

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

What is endoplasmic reticulum (ER)?

A

Sheet like membranes - flattened sacs and tubules
Inside ER is fluid spaces and cisternae

Rough ER:

  • Has ribosomes on surface (where proteins are synthesised and stored)
  • Provides large SA for synthesis of proteins and glycoproteins
  • Provides pathway for transport of materials especially proteins throughout cell (Vesicles)

Smooth ER:

  • Doesn’t have ribosomes on surface
  • Synthesises, stores and transports lips, phospholipids and steroids
  • Synthesises, stores and transports carbohydrates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a TEM?

A

Transmission electron microscope

  • Uses a beam of electrons instead of light -electrons have much smaller wavelength
  • Beam passes through thin slice of specimen prepared in a vacuum
  • denser parts of specimen are darker (absorb more electrons)
  • Very high resolution allows us to see structure of cell in very high detail
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is an SEM?

A

Scanning Electron Microscope

  • Beam of electrons is directed at surface of specimen
  • Beam bounces off surface of specimen and pattern of scattering electrons allows a 3d image
  • Slightly worse resolution than TEM
  • Doesn’t need to be as thin as TEM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Stages of HIV?

A
  1. HIV binds to CD4 receptor on T helper cells
  2. Lipid envelope fuses with cell membrane of T helper cell
  3. HIV RNA and reverse transcriptase is released into T helper cell
  4. Reverse transcriptase turns RNA into DNA
  5. HIV DNA is inserted into T helper cell DNA -whenever T helper cell divides, it copies HIV DNA . HIV DNA remains inactive for long time
  6. HIV DNA eventually becomes activated resulting in new HIV proteins and RNA (Lots of HIV particles in helper cell)
  7. New HIV is released from cell (which dies) and then infects new T helper cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is Golgi Apparatus?

A
  • Consists of flattened sacs (cisternae) with small rounded hollow vesicles
  • Proteins and lipids produced by the ER are passed through Golgi in a strict sequence
  • Modifies proteins, sorts and packages them into Golgi vesicles which are regularly pinched off
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is functions of Golgi?

A
  • Add carbohydrates to proteins to form glycoproteins
  • Produce secretory enzymes
  • Secrete carbohydrates, such as those used in making cell walls
  • Transport, modify and store lipids
  • Form lysosomes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is cell wall?

A

Consists of microfibrils embedded in a matrix
Consists of a number of polysaccharides
Middle lamella marks boundary between adjacent cell walls / cements cells together

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

What is function of Cell wall?

A
  • Provides strength to stop cell bursting under osmotic pressure
  • Provides mechanical strength to plant as a whole
  • Allows water to pass along it and so contribute to movement of water through the plant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a lysosome?

A

Vesicles formed by Golgi that contain enzymes - lysozymes

Lysozymes -enzymes that hydrolyse cell wall of certain bacteria

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

what is function of lysosome?

A
  • Hydrolyse material ingested by phagocytes
  • release enzymes to outside of cell to destroy material around the cell
  • Digest worn out organelles so that chemicals they’re made of can be reused
  • Completely breaks down cells after they have died (autolysis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Structure of viruses?

A

extremely small
have nucleic acid core (DNA or RNA) with outer protein capsid

some:

  • Lipoprotein envelop outside of capsid
  • Receptors
  • Enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

function of viruses?

A

Do not carry out life processes
No metabolism/no ATP, produce produce proteins
Can only be replicated using metabolism of host

17
Q

How does humeral immunity work?

A
  1. Pathogen invades, surface antigens of an invading pathogen are taken up by a B cell
  2. B cell presents antigen on surface
  3. T helper cells attach to antigens and activate
  4. cells divide by mitosis to give clone of plasma cells
  5. Plasma cells produce antibodies
  6. Antibodies attach to antigen on pathogen and destroy it
  7. Some B cells develop into memory cells -these can respond to future infections by the same pathogen by dividing rapidly and developing into plasma cells to produce antibodies.
18
Q

How does cell mediated immunity work?

A
  1. Lymphocytes respond to antigens attached to body cell
  2. Pathogens invade and are phagocytosed
  3. Phagocytes present antigens on surface
  4. Receptors on specific T helper cells compliment antigens
  5. T helper cells activate other T cells to divide
  6. Cloned T cells:
    i. Develop into B memory cells
    ii. Stimulate phagocytes
    iii. Maturation of B cells into plasma cells that secrete antibodies
    iv. Activation of cytoxic T cells which destroy tumour cells and virus infected cells
19
Q

What are monoclonal antibodies?

A

Antibodies produced from a single clone of plasma cells
Have tertiary structure complimentary to one antigen
Can be used for testing, diagnosis and disease treatment

20
Q

Uses of Monoclonal antibodies?

A
  • Separation of a chemical from a mixture
  • Immunoassay - calculating amount of substance in a mixture
  • Pregnancy/HIV/Urine drug tests
  • Cancer treatment - ‘magic bullet’
  • Transplant surgery
21
Q

How does phagocytosis work?

A
  1. Phagocytes are attracted towards pathogen by chemical products of pathogen - moves along conc. gradient (Chemotaxis)
    - Damaged cells also release chemicals
  2. Phagocyte binds to pathogen
  3. Engulfs pathogen to form vesicle known as phagosome
  4. Lysosomes fuse with phagosome - releasing lysozymes and digestive enzymes
    - This forms a phagolysosome
  5. Lysozymes digest/kill microorganisms
  6. The contents of the phagolysosome are eliminated from phagocytes by exocytosis
22
Q

What are the stages of cell division?

A 
Interphase- G1(cell growth)
                  - S (DNA replicated)
                  -G2 (More organelles)
Mitosis:
 - Prophase
- Metaphase
-Anaphase
- Telophase

Cytokinesis -Cytoplasm divides to form more cells

23
Q

What is prophase?

A

Chromosomes condense and coil (become visible)
protein fibres form spindle
Nuclear envelope disappears

24
Q

What is Metaphase?

A

Chromosomes line up ate equators

Chromosomes are seen to be made up of 2 chromatids

25
Q

What is Anaphase?

A

Sister chromatids are pulled to opposite poles by spindle fibres
Centromere holding each pair of sister chromatids together divides
Spindle fibres shorten and pull one of each pair of sister chromatids to opposite poles

26
Q

What is telophase?

A

Two sets of separated chromosomes
new nuclear envelope forms around each set
chromosomes uncoil

27
Q

What is rough ER?

A

Rough ER:

  • Has ribosomes on surface (where proteins are synthesised and stored)
  • Provides large SA for synthesis of proteins and glycoproteins
  • Provides pathway for transport of materials especially proteins throughout cell (Vesicles)
28
Q

What is smooth ER?

A

Smooth ER:

  • Doesn’t have ribosomes on surface
  • Synthesises, stores and transports lips, phospholipids and steroids
  • Synthesises, stores and transports carbohydrates

Biology AS (4 decks)

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