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Biology 2 > Cells and viruses > Flashcards

Cells and viruses Flashcards

(51 cards)

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1
Q

What does the cell theory state

A

New cells are formed from other existing cells and that a cell is a fundamental unit of structure, function, and organisation in all living organisms

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2
Q

What is an exception to the cell theory rule

A

Viruses are an exception because they aren’t made up of cells

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3
Q

In complex organisms, what do cells make

A

Specialised cells –>Tissue–>Organs–>System–>Organisms

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4
Q

Give an example of prokaryotes

A

Bacteria

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5
Q

What is bacteria made up off

A

.Cell wall
.Plasmids
.Nucleotides
.70S ribosome

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6
Q

Describe the cell wall of bacteria

A

.Made up of peptidoglycan which is very thick and protective. Some retain purple stain = gram-positive
.In others the cell wall is thin and does not hold the purple stain. This is known as Gram-negative. The stain turns red

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7
Q

Describe the Plasmids in a prokaryote

A

.Smaller,circular, a single length of DNA

.They often contain genes that aid the bacterium survival

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8
Q

Describe the Nucleoid in a prokaryote

A

.Circular DNA molecule

.DNA is folded in a region which is the nucleoid

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9
Q

Describe the 70S ribosomes in prokaryotes

A

.They make proteins

.Size of the ribosome is 70s in prokaryotes

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10
Q

What are Eukaryotes made up of

A 
.Nucelolous 
.Nucelus
.Centrioles
.Lysosome 
.Golgi apparatus 
.Mitochondria 
.80S ribosome
.sER 
.rER
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11
Q

Describe the nucleolus

A

.Region of dense DNA and protein which makes ribosomes

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12
Q

Describe the nucleus

A

.Surrounded by a double membrane with pores

.Stores DNA

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13
Q

Describe the centrioles

A

.Two hallow cylinders
.Arranged at right angles to each other
Makes a spindle in cell division

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14
Q

Describe the lysosomes

A

.Enclosed by a single membrane
.Containing digestive enzymes
.Destroys old organelles and pathogens

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15
Q

Describe the Golgi apparatus

A

.Seres of single, curved sacs enclosed by a membrane
.Each sac is smaller than the previous one
.Many vesicles luser around it
.Modifies proteins and packages them in vesicles for transport

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16
Q

Describe the 80S ribosome

A

.Site of protein synthesis

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17
Q

Describe the mitochondria

A

.Creates ATP in a process known as cellular respiration
.Can survive on its own as it has its own DNA and ribosome (endosymbiotic theory)
.Contain folded inner membrane = cristae
.Stalked particles and matrix are also within the organelle

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18
Q

Describe the sER

A

.A series of single, tubular sacs made of membrane

.Lipids are made here

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19
Q

Describe the rER

A

. A series of single, flattened sacs enclosed by a membrane
.Ribosomes on the surface
.Protein made here

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20
Q

How is image size calculated

A

Image size = actual size X magnification

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21
Q

What is meant by resolution

Study These Flashcards
A

Being able to see two objects as distinct

22
Q

What is the resolution of the following:

a) Human
b) Light microscope
c) Electron microscope

Study These Flashcards
A

a)0.1mm
b)0.2 micrometer
C)1 nanometer

23
Q

What’s the wavelength of:

a) Light
b) electron beam

Study These Flashcards
A

a) 500nm

b) 1nm

24
Q

When does light microscope work

Study These Flashcards
A

When light passes through a specimen so that it can enter the eye
The specimen must be thin

25
What is staining used to do
To give structure color and contrast and allow identification
26
What are 4 common stains used | what are they used for
1) Iodine solution -stains starch blue-black 2) Ethanoic orcein - stains DNA reddish-purple 3) Methylene blue - stains nuclei and chromosomes blue 4) Phloroglucinol - Stains lignin, found in plant cells, red
27
Explain the disadvantage of the EM
1) All specimens are examined in a vacuum so it is impossible to look at living material 2) The treatment is likely to result in artefacts 3) EMs are still extremely expensive to buy, run and maintain
28
What is a light microscope
LM is a relative sample piece of equipment but it must be set up and used correctly to get the best results
29
What is the set-up of the light microscope
1) Revolve the turret so that the low power lens is pointing down 2) Place the slide on the stage 3) Look through the eyepiece and adjust the mirror to bring light into the field of view 4) Turn the coarse focus knob until the specimen is in the focus 5) Adjust condenser for best lightening 6) Move to a higher power lens when necessary by revolving the turret, readjusting the condenser if needed
30
How is the eye-piece lens calibrated
1) Place a stage micrometer slide on the microscope stage 2) Focus on the scale under a low power lens 3) Align the scales of the eyepiece graticule in and the stage micrometer in the field of view 4) Count the number of divisions of the eyepiece graticule equivalent to a known length on the stage micrometer 5) Work out the length of each eyepiece unit 6) Repeat for the other objective lenses
31
What happens after the calibration in a light microscope
Simply count the number of eyepiece graticule divisions the objects occupies when looking at it and convert to actual units from your calibration
32
Give three rules you need to follow when recording the findings of a light microscope (drawings)
1) Use a sharp pencil 2) Keep lines clear 3) State magnification on drawing
33
How are viruses classified
according to their structure
34
Give three types of viruses
1) DNA viruses -acts as a template for the manufacture of new DNA and mRNA to viral proteins 2) RNA virus- Contains RNA and make new RNA from it (no DNA made) 3) Retrovirus -DNA is incorporated into a host cell and used to make more viral proteins and RNA genomes
35
What are three structural features that would distinguish any virus from any bacterium
1) A virus has no cytoplasm 2) The virus has no ribosome 3) The virus has a protein coat
36
What are viruses
They are not living however they can reproduce within the cells of a living organism
37
What are antivirals
Drugs against viruses that target the process of viral replication
38
What is the Lytic cycle
In which the viral genetic material replicates independently of host DNA New viruses are released by lysis Such viruses are said to be disease-causing (Virulent)
39
What stages do some viruses go through in their lifetime
1) Lytic | 2) Lysogenic
40
What is a Lysogenic cycle
A viral nucleic acid is incorporated into the host cell genetic material and spread through host-cell reproduction. The viral nucleic acid may remain inactive (latent) for years before it starts to replicate. Such viruses are termed non-virulent A host cell that is damaged may trigger activation of viral genetic material, which then enters the lytic cycle and becomes virulent
41
What is the retrovirus cycle
A special case of the lysogenic cyclic
42
How is the RNA in virus transcribed to DNA
Reverse transcriptase
43
How do viruses leave the cell
By exocytosis
44
What causes Ebola symptoms
Ebola viruses symptoms include fever, headache, joint and muscle pain, vomiting and diarrhea
45
How can you prevent the spread of the virus Ebola
1) Affected areas should be isolated 2) Protective equipment such as face masks, goggles, etc 3) Careful hand washing and use of alcohol-based sanitizing gels should be routine 4) Medical equipment must be sterilised and disposed of carefully
46
What are the 4 stages of mitosis
1) Prophase 2) Metaphase 3) Anaphase 4) Telophase
47
What happens during cytokinesis
The cytoplasm divides to form 2 new cells
48
What is the interphase
It has three stages: G1- When growth and protein synthesis occurs S-When the events of DNA replication occurs G2-Wen further growth and protein synthesis occurs
49
What happens during prophase
.Centrioles begin to move to opposite poles. they appear as star-like asters as microtubules form .Chromosomes become coiled up and become visible as 2 chromatids .Nucleolous disappear
50
What happens during Metaphase
.Chromosomes attach to spindle fibre by centromeres
51
What happens during Anaphase
.Centromeres split so sister chromatids can be pulled towards opposite poles .Spindlefibre contracting

Biology 2 (1 decks)

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