Brainscape's Knowledge GenomeTM

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


See full index

Biology > Cell Structure > Flashcards

Cell Structure Flashcards

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

What’s magnification?

A

The number of times larger an image appears, compared with the size of the object. Produce linear magnifications. X100 image is 100 times wider and 100 times longer than the original object

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

What’s an organelle?

A

Small structures within cells, each of which has a specific function

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

What’s a photomicrograph?

A

Photograph of an image seen using an optical microscope

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

What’s resolution?

A

The clarity of an image. The ability of an optical instrument to see or produce an image that shows fine detail clearly

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

Why are optical microscopes still used?

A

Relatively cheap
Easy to use
Portable and able to be used in the field as well as labs
Able to be used to study while living specimens

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

What magnification do optical microscopes allow?

A

Up to x1500

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

What’s an electron micrograph?

A

Photograph of an image seen using an electron microscope

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

Why is an optical microscopes resolution low?

A

Uses visible light which is part of the electromagnetic spectrum. It has a wavelength between 400 and 700 nm therefore structures closer than 200 nm will appear as one object

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

How to set up a optical microscope?

A

Place slide with specimen on the stage and clip into place
Rotate the nosepiece so lowest power lens is over slide.
Adjust the coarse focus know while looking into the eyepiece, until you see a clear image
Whilst viewing, adjust the iris diaphragm for optimum light
Rotate the nosepiece and bring x10 objective into place over the specimen. Look down the ocular tube and use knob to focus the image

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

How to calculate magnification?

A

Total magnification= magnifying power of objective lens x magnifying power of the eyepiece lens

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

About laser scanning microscopes?

A

Use laser light to scan object point by point, assembled by computer into one image
High resolution and high contrast
Depth selectivity and can focus on structures at different depths with specimens
Can observe while living specimens
Used in medical profession and biological research

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

What’s the wavelength of electron microscopes?

A

0.004nm

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

How do electron microscopes work?

A

Electrons fired from a cathode and focused by magnets rather than glass lenses on to a screen or photographic plate

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

About the transmission electron microscope?

A

Specimen has to be chemically fixed by being dehydrated and stained
Beam of electrons pass through specimens. Some pass through and are focused onto screen
Form 2D black image
Magnification of x2000000

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

About the scanning electron microscope?

A

Electrons don’t pass through specimen.
Cause secondary electrons to bounce off the specimens surface and be focused on to a screen
3D image with magnification up to x200000
Black and white
Specimen has to be in vacuum
Coated with fine film of metal

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

Draw backs of an electron microscope?

A

Large and very expensive
Need a great deal of skill and training
Specimens have to be dead
Metallic salt stains may be potentially hazardous to the user

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

What’s the wavelength of electron microscopes?

A

0.004nm

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

How do electron microscopes work?

A

Electrons fired from a cathode and focused by magnets rather than glass lenses on to a screen or photographic plate

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

About the transmission electron microscope?

A

Specimen has to be chemically fixed by being dehydrated and stained
Beam of electrons pass through specimens. Some pass through and are focused onto screen
Form 2D black image
Magnification of x2000000

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

About the scanning electron microscope?

A

Electrons don’t pass through specimen.
Cause secondary electrons to bounce off the specimens surface and be focused on to a screen
3D image with magnification up to x200000
Black and white
Specimen has to be in vacuum
Coated with fine film of metal

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

Draw backs of an electron microscope?

A

Large and very expensive
Need a great deal of skill and training
Specimens have to be dead
Metallic salt stains may be potentially hazardous to the user

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

Examples of specimens that can be viewed by an optical microscope?

A

Living organisms such as Amoeba
Smear preparations or human blood and cheek cells
Thin sections of animals, plant and fungal tissue

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

Observing unstained specimens

A

Some organisms are colourless or transparent. Some microscopes use light interference, rather than light absorption, in order to produce a clear image without staining
Some use a dark background

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

Why stain specimens?

A

Coloured chemicals that bind to molecules on or in the specimen. Some stains bind to specific structures so they can be easily identified
This is called differential staining

Iodine stains cellulose yellow and starch granules blue/black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How to make permanently fixed slides?

A

Dehydrating the specimens
Embedding them in a wax to prevent distortion during slicing
Using a special instrument to make very thin slices called sections
These are stained and mounter in a special chemical to preserve them

26
Q

What’s the magnification formula?

A

Magnification = image/actual

27
Q

What’s an eyepiece graticule?

A

A measuring device. It is places in the eyepiece of a microscope and acts as a ruler when you view an object under the microscope

28
Q

What’s a stage graticule?

A

A precise measuring device. It is a small scale that is placed on a microscope stage and used to calibrate the value of eyepiece divisions at different magnifications.

29
Q

Using a stage graticule to calibrate eyepiece graticule

A

Insert eyepiece graticule into x10 eyepiece or microscope
Place stage graticule on the stage and bring it into focus using lowest power objective
Align the 2 graticules
Check the value of one eyepiece division at the magnification
Divide the stage graticule by the amount of eyepiece units that fit into it
This gives how much each division is worth

30
Q

What is division of labour?

A

Every cells can carry out its many functions efficiently

31
Q

Structure of nucleus, nuclear envelope and nucleolus

A

Nucleus surrounding by double membrane called nuclear envelope. There are pores in the nuclear envelope
Nucleolus has no membrane. Contains RNA
Chromatic(genetic material) consisting of DNA wound around histone proteins

32
Q

Nucleus, nuclear envelope and nucleolus function

A

Envelope separates contents of nucleus from rest or cell.
Outer and inner nuclear membrane fuse. Here some dissolved substances and rips ones can pass through
Pores enable larger substances to leave
Nucleolus is where ribosome r made
Chromosomes contain organisms genes

Nucleus 
Control centre of cell 
Stores organisms genome 
Transmits genetic information 
Provides instructions for protein synthesis
33
Q

Structure of rough endoplasmic reticulum

A

System of membranes containing fluid filled cavities that are continuous with nuclear membrane
Coated within ribosomes

34
Q

Function of rough endoplasmic reticulum

A

Intercellular transport system
Cisternae form channels for transporting substances from one area to another
Provides large surface area for ribosomes

35
Q

Smooth endoplasmic reticulum structure

A

System of membranes, containing fluid filled cavities that are continuous with the nuclear membrane
No ribosomes on its surface

36
Q

Function of smooth endoplasmic reticulum

A

Contains enzymes that catalyse reactions involved with lipid metabolism
Synthesis of cholesterol, lipids, steroid hormones
Involved with absorption, synthesis and transport of lipids

37
Q

Structure of Golgi apparatus

A

Consists of a stack of membrane bound flattened sacs

Vesicles bring materials to and from here

38
Q

Function of Golgi apparatus

A

Proteins are modified
Packaging and pinching of vesicles
Then stored in cell
Or exported out of the cell

39
Q

Structure of mitochondria

A

Spherical rod shaped or branched
2-5 microm.
Surrounded by 2 membranes with fluid filled space between them
Inner membrane highly folded into cristae
Inner part is a fluid filled matrix

40
Q

Mitochondria function

A

Site of ATP production during aerobic respiration
Self replicating
Abundant in cells where much metabolic activity takes place

41
Q

Chloroplast structure

A 
4-10microm 
In plants and some protoctists
Double membrane 
Inner membrane is continuous with thylakoids which contain chlorophyll 
Contains loops of DNA and starch grains
42
Q

Chloroplast function

A

Site of photosynthesis

43
Q

Vacuole structure

A

Surrounded by membrane called tonoplast and contains fluid

44
Q

Vacuole function

A

Plants have large permanent vacuoles
Maintains cell stability
Helps support the plant

45
Q

Lysosomes structure

A

Small bags formed by Golgi. Surrounded by signs membrane

Contain powerful hydrolytic enzymes

46
Q

Lysosomes function

A

Keep powerful hydrolytic enzymes separate from cell

Engulf old cell organelles and foreign matter, digests them and returns parts to be reused

47
Q

Structure of cilia and undulipodia

A

Protrusions from the cell and surrounded by cell surface membrane
Contains microtubules
Formed from centrioles

48
Q

Function of cilia and undulipodia

A

Epithelial cells lining has cilia to move band of mucus
Act as an antenna. Acts as receptor and allows cells to detect signals
Undulipodium allows spermatozoon to move

49
Q

Ribosome structure

A 
Small spherical 
20nm 
Made of ribosomal RNA 
Made in nucleolus as 2 separate subunits which combine outside envelope 
Either free in cytoplasm or on RER
50
Q

Ribosome function

A

Protein synthesis

51
Q

Centriole structure

A

Consists of 2 bundles of microtubules at right angles to each other
Microtubules made of tingling protein subunits

52
Q

Centriole function

A

The spindles

Involved in the formation of undulipodia and cilia

53
Q

Cytoskeleton structure

A

Network of protein structures
Rod like microfilaments made of subunits of protein actin
Intermediate filaments
Straight cylindrical microtubules made of protein subunits called tubulin
Cytoskeleton motor proteins

54
Q

What are cytoskeleton motor proteins?

A

Enzymes that have a site that binds to and allows hydrolysis of ATP as their energy source

55
Q

Cytoskeleton function

A 
Give support and mechanical strength. 
Cell stability
Movement of organelles 
Movement of vesicles
Spindles before cell division 
Cilia undulipodia and centrioles 
Anchor the nucleus 
Enables cell signalling
56
Q

Cellulose cell wall structure

A

Made of bundles of cellulose fibres

57
Q

Cellulose cell wall function

A

Strong and prevents bursting
Support
Maintains cell shape
Permeable

58
Q

How is a protein made and secreted

A

Gene that has code for protein is transcribed into a length of mRNA
Pass out nuclear pores to ribosome
Instructions are translated into polypeptide chain
Pass into cisternae of RER and pinched off
Travels to Golgi with motor proteins aid
Modification
Pinched off again and fuses to cell wall

59
Q

How are prokaryotic cells similar to eukaryotic

A

A plasma membrane
Cytoplasm
Ribosomes
DNA and RNA

60
Q

How are prokaryotic cells different to eukaryotic

A 
Much smaller 
Less well developed cytoskeleton  and no centrioles 
No nucleus 
No membrane bound organelles 
Smaller ribosomes 
Naked DNA 
Some have-
Protective waxy capsule 
Plasmids
Flagella 
Pili
61
Q

How do prokaryotic cells divide?

A

Binary fission

Biology (6 decks)

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