Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology As > Cell structure > Flashcards

Cell structure Flashcards

(65 cards)

Start Studying
1
Q

How do light microscopes work?

A

By projecting light through a specimen, then focusing it with a series of lenses to magnify the image.

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

What is the equation for magnification?

A

Magnification = image size + object size

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

What will happen if you increase the magnification?

A

it may not be useful due to the lists of resolution of light

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

symbol for meters?

A

m

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

symbol for decimeters?

A

dm

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

symbol for centimeters?

A

cm

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

symbol for millimeters?

A

mm

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

symbol for micrometers?

A

um

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

symbol for nanometers?

A

nm

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

What must you do when using the magnification equation?

A

You must ensure that all the units are the same

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

What do you decimetre metres by to convert it into meters?

A

x10-1

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

What do you centimetre metres by to convert it into meters?

A

x10-2

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

What do you millimetre metres by to convert it into meters?

A

x10-3

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

What do you micrometer metres by to convert it into meters?

A

x10-6

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

What do you nanometre metres by to convert it into meters?

A

x10-9

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

What is resolution?

A

It is the ability to distinguish between 2 separate points. Increasing the resolution allows you to see more detail (unlike magnification which shows you the image at a bigger or smaller scale)

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

What is the laser scanning confocal microscope?

A

The still use a light beam to produce an image, but scan each object point by point, then use a computer to assemble the entire image. They produce good resolution and can be used at different depths on the specimen

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

How does an electrons microscope work?

A

It generates a beam of electrons with a wavelength 100, 000 times smaller than that of light. This means that they have maximum resolution of 0.2nm, allowing much smaller structures to be seen. The beam is focused with a series of magnets.

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

What are the two types of electron meters?

A

Transmission electron microscopes (TEM)

Scanning Electrons Microscopes (SEM)

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

What does the transmission electron microscope do?

A

They pass the beam of electrons through a prepared sample, producing a 2D image called an electron micrograph
The maximum magnification is x2,000,000 (possibly up to x50 million)

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

What does the scanning electrons microscope do?

A

They bounce the electron beam off of the sample, producing a 3D image.
The maximum magnification is x200,000

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

What are the advantages of electron microscopes?

A

Much higher magnification than light microscopes
Much higher resolution than light microscopes
Colour can be added later by computer software, producing false-colour micrographs which are easy to study

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

What are the disadvantages of electron microscopes?

A

Electron beams are stopped by air / water molecules, so the specimens must be dried out (killed) and placed in a vacuum
EMs are very expensive and difficult to prepare specimens for

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does the cell theory state?

A

All living things consist of cells
New cells can only be formed from the division of pre-existing cells
All cells contain information that instructs for the growth of that cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Describe the plasma membrane
Description: Surrounds the cell. Has a fluid mosaic structure Function: Selective barrier, retaining cell contents Size: 7-10nm thick
26
Describe the rough endoplasmic reticulum (rough ER)
Description: intercellular membrane system cared with ribosomes Function: Carries out protein synthesis due to the ribosomes. Intercellular transport Size: variable
27
Describe the smooth endoplasmic reticulum (smooth ER)
Description: Intercellular membrane system without ribosomes Function: synthesis of lipids (fats), including steroids Size: variable
28
Describe the Golgi apparatus
Description: Specialised smooth ER. Consists of a stack of membrane-bound flattered sacs Function: Modification and packaging of molecules such as glycoproteins, polysaccharides, hormones which are released by the rough ER Size: variable
29
Describe the ribosomes
Description: Small, complex structures. Either attached to rough ER or free in cytoplasm Function: carry out protein synthesis Size: 25nm diametre
30
Describe the nucleus
Description: major cell organelle containing chromatin (DNA and histones) Function: Regulates activities of cells. Carries hereditary information Size: 20 um diametre
31
Describe the nuclear envolope
Description: double membrane surrounding nucleus, with nuclear pores Function: Regulates exchange between nucleus and sutoplasm. Some Protein synthesis then continues into the Rough ER Size: 2 x10 nm
32
Describe the nucleolus
Description: Specialised region of the nucleus, not surrounded by a membrane Function: Synthesis of RNE and ribosomes Size: 2 um diametre
33
Describe the mitochondria
Description: Double-membrane organelle containing enzymes on their surfaces for respiration folded inner membrane formes finger-like projections called cristal with a fluid in the spaces called the matrix Function: carries out respiration to produce ATP Size: 2-5 um diameter
34
Why may mitochondria look different?
- They may be seen in different sections - They may have been damages during the reparation of he slide - They may be of different ages - They will vary in size naturally, even within the same cell
35
Describe the chloroplast
Description: plant cell organelle with double membrane. Inner membrane continuous with flattened membrane sacs called thylakoids. A stack of these is called a grain. They are connected by lamellae. The fluid filled region in the middle is called the storm. It may contain a number of starch grains or lipid droplets Function: carries out photosynthesis - chlorophyll molecules on the inner membrane capture sunlight, which is used to make carbohydrates from water and CO2 Size: 4-10 um
36
Describe the cell wall
Description: Plant structure of cellulose mircofibrils Function: Support and protection of the ell Size: 5 micrometers thick
37
Describe the lysosome
Description: Spherical membrane - bound vesicles containing enzymes Function: carries out intercellular digestion Size: 50nm diameter
38
Describe the vacuole:
Description: it is surrounded by a membrane called tonoplast, and contains fluid Function: Helps support the plant Size: variable
39
Describe the Flagella and Celia
They re hair like extensions from which the surface of the cell. Each one is made up of a ring of 9 microtubules, with 2 microtubules in the center - called a 9 + 2 arrangement
40
Where is flagella found and what is its function
It is usually fund in ones or twos on a cell and are much longer than Celia. They can be used to move a cell around e.g. bacteria often have the (although microtubules arrangement is different)
41
Where is Celia found and what is its function
Usually found in large numbers on the cell surface and around 10um long. They sweep substances across the cell surface e.g. eggs in the oviduct mucus in the trachea
42
What is the cytoskeleton and what does it do?
The are a network of rotten fibres found in all cells, which provide an internal framework ro keep the cell's shape
43
What are the main fibres in cytoskeleton calles, and what are they?
They are called, microtubes, which are cylinders of protein called tumbling and are 25nm in diameter.
44
What can microtubes be used for?
It can be used to move a micro-organism through a liquid or to move organelles around inside the cell. e.g. They form centrioles, which move chromosomes during mitosis They help vesicle move from the endoplasmic reticulum to the Golgi apparatus The proteins which cause the movement are called mirotuble motor, and use energy (ATP) to drive the movements
45
Each different organelle has a ........ ........ within the cell. This is called a ....... .... ......, as each organelle contribute to the overall survival of the cell
specific function | division of labour
46
What are the two cell groups?
Eukaryotic and prokaryotic
47
Describe prokaryotic cells and how they differ from prokaryotic cells
They are bacteria which do not have a separate nucleus, or any member bound organelles They are are much smaller than eukaryotic cells. There DNA is 'naked' as it is not wound around portions called histones Some structures are common to all prokaryotic cells but others are only found in some species
48
Can you find a nucleus in eukaryotic/prokaryotic cells
Eukaryotic: Usually present (surrounded by a nuclear envelope and containing nucleolus) Prokaryotic: NO
49
Can you find a mitochondria in eukaryotic/prokaryotic cells
Eukaryotic: usually present Prokaryotic: NO
50
Can you find a rough ER and smooth ER) in eukaryotic/prokaryotic cells
Eukaryotic: always Prokaryotic: NO
51
Can you find a ribosomes in eukaryotic/prokaryotic cells
Eukaryotic: Yes, relatively large Prokaryotic: Yes, relatively small
52
Can you find a cytoskeleton in eukaryotic/prokaryotic cells
Eukaryotic: Always Prokaryotic: NO
53
Can you find chromosome in eukaryotic/prokaryotic cells
Eukaryotic: Yes, DNA arranged in several long strands, associated with histones Prokaryotic: Yes, DNA circular
54
Can you find a cell wall in eukaryotic/prokaryotic cells
Eukaryotic: Yes, in plants Prokaryotic: Always, made up of peptidoglycan
55
Can you find cilia and flagella in eukaryotic/prokaryotic cells
Eukaryotic: Sometimes Prokaryotic: Some flagella
56
Can you find chloroplast in eukaryotic/prokaryotic cells
Eukaryotic: Present in some plant cells Prokaryotic: NO
57
What structure contains RNA and not DNA?
ribosomes
58
What is the maximum magnification of a light microscope?
x1500
59
What is the maximum resolution for a light microscope?
200 nm
60
What is the maximum magnification of a TEM?
x2 million
61
Convert 0.15 micrometres into nanometres
150nm
62
Which process involves mRNA instructions being used to create proteins at the ribosomes?
translation
63
Why do we need staining for light and electron microscopes?
- Very high contrast. The stain absorbs electrons in much higher amounts than the surrounding medium. Therefore, different regions of the sample have different electron densities and can be differentiated easier in the resulting projections. - The radiation damage from the absorbed electrons is mostly irrelevant because it does not affect stain salts at the same rate as the organic molecules of the sample. - The sample is easy to prepare. Generation of a negative stained grid takes less than four minutes and no fancy apparatus.
64
Describe the structure and functions of centrioles
Structure: They consists of two bundles of microtubes at right angles from each other. the microtubules are made of tubulin protein subunits and are arranged to fork a cylinder. Function: The main function of the centriole is to help with cell division in animal cells. Celiogenesis is simply the formation of cilia and flagella on the surface of cells. Before the cilia is formed the centrioles multiply and line up beneath the cell surface membrane. Microtubules then sprout outwards from each centriole, forming a cilium or undulipodium
65
Why si the cytoskeleton important?
It forms a framework for the movement of organelles around the cytoplasm - most of the organelles are attached to the cytoskeleton. The network consists of protein microfilaments, intermediate filaments, and microtubules. The cytoskeleton provides an important structural framework for: Cell shape

Biology As (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions