Brainscape's Knowledge GenomeTM

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


See full index

A-level Biology > Cells and microscopes > Flashcards

Cells and microscopes Flashcards

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

what are eukaryotic cells

A

have a nucleus and organelles enclosed within membranes (e.g. mitochondrion)
can become specialised for specific functions

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

cell membrane

A

phospholipid bilayer is partially permeable so can control substances going in and out of the cell

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

nucleus

A

enclosed by a double membrane

contains chromosomes consisting of protein bound li near DNA and one or more nuclei

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

what does DNA control

A

protein synthesis

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

what do nucleoli make

A

ribosomes

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

mitochondria

A

rod shaped cell consisting of outer and inner membrane
inner membrane folds to form cristae containing ribosomes, enzymes and circular DNA molecule
increases the SA for enzymes and other proteins of respiration
site of aerobic respiration
produces ATP

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

chloroplasts

A

surrounded by two highly selective membranes containing a stroma

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

what does the stroma of a chloroplast contain

A

a system of membranes, circular DNA molecule, ribosomes, starch grains and enzymes of photosynthesis

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

what do the stacked membranes of a chloroplast form and what do they do

A

forms grana containing chlorophyll

provides a high SA for chlorophyll, electron carrier and enzymes of photosynthesis

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

Golgi apparatus

A

stack of flattened membrane bound sacs of cytoplasm
receives and prepares proteins synthesised on the endoplasmic reticulum to be secreted out of the cell
makes glycoproteins = carbohydrates + proteins

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

Golgi vesicle

A

transport glycoproteins and release its contents when fused with cell membrane

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

lysosomes

A

type of Golgi vesicle which contains digestive enzymes called lysozymes
lysozymes hydrolyse cell walls of bacteria
breaks down old organelles and cells and digests contents of vacuole to reuse useful chemicals

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

ribosomes

A

not bound by a membrane and made up of RNA and protein
consists of a large and small subunit
uses information in nucleic acid to synthesise proteins

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

endoplasmic reticulum

A

network of flattened membrane sacs called cirsternae forming a system of channels for transporting materials through the cytoplasm and storing glycoproteins and proteins

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

rough ER

A

transports proteins and contains ribosomes on the cytoplasmic side
provides high SA for glycoprotein and protein synthesis

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

smooth ER

A

does not contain ribosomes

synthesises and transports lipids and carbohydrates

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

cell wall

A

made up of cellulose microfibrils and other polysaccharides
provides mechanical support and protection (prevents cell from bursting from turgor pressure)
allows water to pass along it through the plant

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

vacuole

A

sac bounded by a single membrane (tonoplast) containing cell sap made up of a solution of mineral salts, pigments and organic acid
stores waste products
changes in its volume affects the turgidity of the cell
contains pigments resulting in colour petals which attract pollinating insects

19
Q

centriole

A

spindle-shaped structure of protein fibres on which the chromosomes move during nuclear division

20
Q

how are prokaryotic cells different to eukaryotic cells (8)

A

smaller and contains smaller ribosomes
does not contain membrane bound organelles
no nucleus
contains circular DNA not associated with proteins called a plasmid
cell wall is made of a glycoprotein called murein
contains a capsule - an outer mucilaginous layer
may have one or more flagellum

21
Q

virus (5)

A

acellular and non-living
contains genetic material in the form of RNA or DNA
has a protein coat called a capsid enclosing nucleic acids
can only multiply in living host cells
have attachment proeins

22
Q

what do attachment proteins do

A

identifies and attaches to a host cell

23
Q

magnification definition

A

how many times bigger the image is compared to the real object

24
Q

magnification equation (objects)

A

= apparent size of image/ actual size of object

25
Q

magnification equation (scale bar)

A

= length of scale bar/ length scale bar represents

26
Q

resolution definition

A

minimum distance apart that two objects can be in order to appear as separate items

27
Q

how many lens systems does a optical (light) microscope have

A

3
eye piece
objective lens
condenser

28
Q

properties of an image from a optical (light) microscope

A

coloured, inverted, low resolution

29
Q

why do optical (light) microscopes have a low resolution

A

light has a relatively long wavelength

30
Q

transmissions electron microscope (TEM)

A

parts of the specimen absorb the electrons from below and some let it pass through

31
Q

limitations of transmissions electron microscope (TEM)

A

high energy electrons may destroy the specimen so limits resolution
vacuum so unable to observe living things
specimen needs to be thin to allow electrons to penetrate areas

32
Q

properties of an image from a transmissions electron microscope (TEM)

A

flat, 2D, no colour

33
Q

scanning electron microscope (SEM)

A

beam of electrons from above are passed back and forth at a specific portion so specimen does not need to be thin
contours of specimen scatters the electrons forming a pattern producing a monochromatic, 3D image

34
Q

limitations of scanning electron microscope (SEM)

A

vacuum so no living specimens

has a lower resolution that TEM but higher than optical microscope

35
Q

what is cell fractionation

A

process where cells are broken up and organelles are separated out

36
Q

what are the three processes of cell fractionation

A

placing the tissue in a specific solution
homogenisation
ultracentrifugation

37
Q

what solution is the tissue placed in for cell fractionation

A

cold, buffered, isotonic

38
Q

why is the tissue placed in a cold solution

A

reduces enzyme activity which might break down organelles

39
Q

why is the tissue placed in a buffered solution

A

keeps pH constant so there are no changed in structures of organelles which affect their function

40
Q

why is the tissue placed in an isotonic solution

A

prevents cells from bursting (osmostic gain) or shrinking (water loss)

41
Q

what is homogenisation

A

cells are broken up by a homogenizer (blender)
releases organelles from cells
homogenate is filtered to remove any complete cells

42
Q

what is ultracentrifugation

A

filtered homogenate is put into a centrifuge where the organelles separate
centrifuge spins tubes of homogenate at a high speed to create a centrifugal force
heaviest organelles such as nuclei sink down to form the sediment pellet
lightest organelles make up the fluid at the top called the supernatant

43
Q

how to measure cells

A

Calibrate an eye piece graticule using a stage micrometer
Measure length with eye piece graticule
Each unit on the micrometer scale is 10 µm

A-level Biology (14 decks)

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