Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology Module 1 > Chapter 2: Basic Components Of Living Systems > Flashcards

Chapter 2: Basic Components Of Living Systems Flashcards

(86 cards)

Start Studying
1
Q

Microscope

A

An instrument that allows you to magnify cells and see details of their ultrastructure

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

Advantages of light microscopes

A

Can observe living and dead things
Does not use harsh chemicals
Easy to setup and use
Cheap and portable

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

Disadvantages of light microscopes

A 
Low magnification (x2000)
Low resolution (200nm)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is transmission electron microscopy?

A

Beam of electrons
Transmitted through a specimen
Focused to produce an image

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

Advantages of transmission electron microscopy

A 
High magnification (x 5 000 000)
High resolution (0.5nm)
Can see internal cell structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is scanning electron microscopy?

A

Beam of electrons
Sent across surface of specimen
Electrons reflected and collected to produce image

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

Advantages of scanning electron microscopy

A 
High magnification (x 500 000)
High resolution (3-10nm)
Can see the surface of cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Disadvantages of transmission electron microscopy

A

Can only see dead material
Harsh chemicals used in prep
Expensive

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

Disadvantages of scanning electron microscopy

A

Can only see dead material
Harsh chemicals used (damaging to cell stature)
Expensive

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

What is laser scanning confocal microscopy?

A

Single spot of focused light
Moves across thin section of specimen
Light re-emitted is filtered through a pinhole aperture

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

Advantages of laser scanning confocal microscopy

A

Can see living cells - non invasive
Can observe cell processes - tracking
Higher resolution than light microscopy

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

Disadvantages of laser scanning confocal microscopy

A

Low magnification (x 2000)
More expensive than light microscope
Only a 2D image is produced

… 3D by creating images at different focal planes

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

Three cell theory statements

A

Plants and animals are composed of cells
Cells are the basic unit of all life
Cells can only develop from existing cells

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

What is brightfield microscopy?

A

Sample is illuminated from below

Observed from above

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

What is whitefield microscopy?

A

Whole sample is illuminated at once

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

Disadvantages of using microscopes

A

Organelles have low contrast in images

Cells do not absorb much light

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

How the general disadvantage of using microscopes can be overcome

A

Use stains

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

What is the purpose of staining cells?

A

Increase contrast
Different components absorb different amounts
Easier to differentiate between organelles

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

What are the four methods of preparation for sample light microscopy?

A

Dry mount
Wet mount
Squash slides
Smear slides

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

What is a dry mount?

A

Solid specimen
Sectioned
Placed between slide and cover slip

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

What is a wet mount?

A

Specimens are suspended in liquid

Cover slip is placed on top of slide

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

What is a squash slide?

A

Wet mount is prepared

Lens tissue is used to press down cover slip on slide

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

What is a smear slide?

A

Edge of a slide
Smears sample thinly and evenly on another slide
Cover slip is placed on top of slide with the smear

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

What are the two lenses in a compound microscope called?

A

Objective lens - placed near the object to produce a magnified image

Eyepiece lens - used to view the object and further magnify the object - reducing chromatic aberration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How do you prepare a sample for staining?
``` Sample placed on slide Allowed to air dry Passed through flame Sample adhered to slide Able to take up stains ```
26
What happens when positively charged dyes are used to stain cells?
Attracted to negatively charged materials in the cytoplasm
27
Name two common dyes
Methylene blue | Crystal violet
28
What is the charge of cystosol in cells?
Negative
29
What happens when negative dues are used to stain cells?
Negative charged components in the cytoplasm repel the dye | Cells are left unstained and so stand out against stained background
30
What is the purpose of differential staining?
Used to differentiate between two types of organisms that are somewhat similar Used to differentiate between different organelles of a single organism in a tissue sample
31
Describe the gram stain technique
Separates bacteria into positive and negative groups Crystal violet used to stain cells -> Iodine fixes the dye -> Sample is washed with alcohol -> Positive bacteria retain the stain (thicker cell walls)
32
What does a counterstain do?
Safranin dye makes gram-negative bacteria turn red, whereas the crystal violet left them colourless Due to their thinner cell walls, gram-negative bacteria do not retain due and are not susceptible to penicillin ... inhibits cell wall formation
33
Describe the acid-fast technique
Used to separate different species of Mycobacterium -> Lipid solvent carries carbolfusion dye into the cells -> Cells are washed with a dilute acid-alcohol solution -> Mycobacterium retain the stain and turn red -> Other bacteria are exposed to the blue methylene stain
34
What are the four methods of producing slides?
Fixing - chemical, preserve cells, near-natural state Sectioning - alcohols, dehydrate cells, placed in mould, sliced thinly Staining - dyes, multiple ones used to show multiple structures Mounting - sample being secured between a slide and cover slip
35
What do scientific drawings include?
``` Title Magnification Smooth continuous line No shading Straight lines parallel to page ```
36
What is an artefact?
A visible structural detail caused by processing the specimen but is not a feature of it E.g. Bubbles trapped under a cover slip
37
What is the purpose of a dichroic mirror in a laser scanning confocal microscope?
It reflects one wavelength but allows other wavelength to pass through - non blurred image
38
What is the purpose of antibodies with fluorescent tags?
Laser scanning confocal microscopy allows specific features to be targeted and studied with more precision than when using staining and light microscopy
39
How do fluorescent tags work?
They emit bright green light when illuminated by UV light Genetically engineered to fluoresce different colours so different structures can be studied Non invasive technique - gene is isolated and attached to the genes coding for proteins Allows study of production and distribution of proteins in cells and organisms
40
Define magnification
By how many time the image has been enlarged Objective lens
41
Define resolution
How much detail the object can be viewed in - limited by diffraction
42
Define diffraction
The tendency of light waves to disperse as they pass close to physical structures in the specimen being studied - causing loss of detail
43
Define resolved
Seen separately
44
How can resolution be increased?
Using beams of electrons which have wavelengths thousands of times shorter than light ... beams can be closer together before overlapping
45
Magnification formula
Magnification = image / object
46
What is the use of an eyepiece graticule?
Used to measure the size of a sample under a microscope Glass disk marked with a fine scale of 1 to 100 which has no units and remains unchanged Relative size of division increases with each magnification factor
47
What is the use of a stage micrometer?
A microscope slide with a very accurate scale in micrometers (um) 100 divisions = 1mm 1 division a 0.01mm
48
Measurement equation
Measurement = graticule divisions X magnification factor
49
Define prokaryote
Single-celled organism
50
Define eukaryote
Multicellular organism
51
What is metabolism?
The rate at which molecules are synthesised or broken down
52
What is a membrane?
Controls what substances enter and exit the cell | Selectively permeable to maintain the cell environment
53
Definition of nucleus
Contains DNA - > directs synthesis of proteins - > controls metabolic activities
54
What is the nuclear envelope?
Double membrane with pores | Protects DNA from damage from the low pH of the cytoplasm in a cell
55
What is the nucleolus?
In the nucleus Produces ribosomes Composed of RNA (which make proteins)
56
What is a mitochondrion?
Double membrane organelle Inner membrane is highly folded (cristae) Cristae contain the matrix (fluid) and enzymes - for the production of ATP
57
What is a vesicle?
Singular membranous sac with storage and transport roles
58
What are lysosomes?
Specialised vesicle Contains hydrologic enzymes Break down waste materials and pathogens Apoptosis 'programmed cell death'
59
What is the cytoskeleton?
Network of fibres Provide shape and stability Microfilaments - contractile fibres, made of protein actin, responsible for cell movement and contraction Microtubules - compose spindles fibres (segregate chromosomes in cell division), formed by the polymerisation of globular tubular proteins
60
What are intermediate fibres?
Fibres made of proteins Provide mechanical strength Help maintain cell integrity
61
What are centrioles?
Components of the cytoskeleton that are composed of micro tubules 2 associated centrioles form a centrosome ...involved in the assembly and organisation of spindle fibres
62
What is a flagella?
Primary function - cell movement Secondary function - sensory organelle, fetch change in cell environment
63
What are cilia?
Stationary - present on surface - sensory organelle Mobile - beat in a rhythmic manner creating a current to move fluids with trapped pathogens
64
Which four organelles coordinate the production of proteins in cells?
Ribosomes ER Golgi apparatus Cytoskeleton
65
What is the endoplasmic reticulum?
A network of membranes enclosing cisternae which is connected to the nuclear envelope
66
What is the smooth ER?
Responsible for lipid and carbohydrate synthesis and storage
67
What is the rough ER?
Has ribosomes bound to the surface | Responsible for the synthesis and transport of proteins
68
What is a ribosome?
Organelle where protein synthesis occurs | Contrasted of RNA made in the nucleolus used to make proteins
69
What is the Golgi apparatus?
Organelle which modifies and packages proteins into vesicles for transport
70
Define exocytosis
Vesicles fuse with the cell surface membrane for secretion out of the cell Some form lysosomes
71
Define endocytosis
Movement of substances into the cell
72
Define phagocytosis
Movement through solid e.g. Lysosomes engulfing something
73
Define pinocytosis
Movement through liquid e.g. Vesicle through the cytoplasm
74
Define transcription
The copying of DNA so mRNA can exit the nucleus and cell and go to the ER ribosomes
75
Define translation
The assembly of amino acids into proteins in the ribosomes of the ER
76
What is the cell wall?
Give plants shape and support (turgor from vacuole) | Freely permeable membrane made of cellulose which acts as a barrier
77
What is a vacuole?
Membrane lined sacs in cytoplasm | Contains cell sap which maintains turgor
78
What is a chloroplast?
Organelle with a double membrane (containing stroma, DNA and ribosomes) Responsible for photosynthesis Thylakoids -> Granum (joined by lamellae)
79
What is chlorophyll?
A green pigment from which photosynthesis occurs and produces starch
80
What are extremophiles?
Organisms that can survive in extreme environments
81
How do flagella move?
Filament is attached to the cell me ante by a basal body and rotates by a molecular motor by the energy supplied by chemiosmosis
82
What form is DNA in cells?
Supercoiled -> Histones -> Chromatin
83
How does DNA structure differ in P and E cells?
P - circular (proteins fold and condense) | E - linear (associated proteins, Histones)
84
What are cell walls made of?
P - peptidoglycon | E - chitin=fungi, cellulose=plants, none in animal
85
How do the size of ribosomes differ in P and E cells?
70s - P | 80s - E
86
How do cells in P and E cells reproduce?
P - binary fission | E - asexual or sexual

Biology Module 1 (1 decks)

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