Brainscape's Knowledge GenomeTM

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


See full index

Biology A Level > Topic 2: Microscopes and magnification > Flashcards

Topic 2: Microscopes and magnification Flashcards

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

Define resolution.

A

A measure of the microscopes ability to distinguish between two close prints on an object or between two close objects. How clear the image is.

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

Define magnification.

A

The object’s increase in size when observed with a microscope, it is expressed with a ratio.

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

Describe a light microscope.

A

A microscope that requires a might much to work either from an external source reflected by a mirror or by a built in light pointing directly at the lens. Or works by passing light through the object you’re viewing and focusing the light through the lenses which magnifies the image through light refraction. The best light microscopes can magnify up to x1500

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

Describe a scanning electron microscope

A

Its users a beam of electrons to view a magnified image. A beam of electrons is moved back and forth over a cell’s surface which creates the detail. SEMs are able to knock electrons off the object these lost electrons come together to form an image, watch due to this can be 3D

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

Describe a transmission electron microscope

A

REMs use a beam of electrons to create as magnified image. High energy electrons are used to penetrate the cell and provide details of a cell’s internal structure. The sample must be thin.

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

What is the structure of the cell membrane?

A

Consists of a phospholipid bilayer that is about 7nm thick. Hydrophilic heads form the inner and outer surfaces and the hydrophobic tails form the inside of the membrane. The structure is described as fluid mosaic model - made of many constantly moving structures within the bilayer. Cholesterol molecules are embedded between the phospholipids to prevent too much movement. Channel proteins and carrier proteins are found within the bilayer to allow large molecules and ions to be transported across. Therefore the membrane is partially permeable. Receptor proteins, glycoproteins and glycolipids are scattered through the membrane.

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

What is the structure of the cell membrane?

A

Consists of a phospholipid bilayer that is about 7nm thick. Hydrophilic heads form the inner and outer surfaces and the hydrophobic tails form the inside of the membrane. The structure is described as fluid mosaic model - made of many constantly moving structures within the bilayer. Cholesterol molecules are embedded between the phospholipids to prevent too much movement. Channel proteins and carrier proteins are found within the bilayer to allow large molecules and ions to be transported across. Therefore the membrane is partially permeable. Receptor proteins, glycoproteins and glycolipids are scattered through the membrane.

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

What is the function of the cell membrane?

A

Physical barrier - prevents the movement of foreign bodies and other molecules entering the cell.

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

What do the glycoproteins and glycolipids do?

A

Respond to insulin in liver cells resulting in the cells absorbing glucose from the bloodstream.
Establishing blood type.
Immune responses.
Responding to neurotransmitters involved in nervous responses

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

Name the parts of the nucleus.

A

Nucleolus, chromatin, nuclear envelope, nuclear pore

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

What is the structure of the nucleus?

A

Has a double membrane (nuclear envelope ), with small spaces in it (nuclear pores).
Chromatin (contains DNA and protein is scattered throughout.
Nucleolus consists of DNA, RNA, and proteins

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

What is the function of a nucleus?

A

Cousins the functions of the cell through DNA transcription. Controls gene expression, protein synthesis, storing DNA. Protein synthesis and ribosome production occurs in the nucleolus

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

What’s the purpose of the nuclear pores?

A

To allow mRNA to leave the nucleus.

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

What happens to the chromatin when cells divide?

A

Condenses into visible chromosomes

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

What is the structure of a ribosome?

A

Made of two subunits (small subunit and large subunit). Very small. Consists of ribosomal proteins and ribosomal RNA (rRNA). No membrane. Often line RER.

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

What’s the function of a ribosome?

A

Protein synthesis from mRNA during translation

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

What is the structure of the rough endoplasmic reticulum?

A

Network of channel-like structures filled with fluid linked to the nuclear membrane with tubules. Is lined with ribosomes

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

What is the function of the RER?

A

Works with the ribosomes to process and produce the 3D structures of proteins. Site of glycoprotein synthesis.

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

What is the structure of the smooth endoplasmic reticulum?

A

Very similar to RER but no ribosomes. Linked to the RER and nuclear membrane. Large surface area for rate of synthesis of lipids and order molecules.

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

What is the function of the SER?

A

Storing, synthesising, and processing lipids, phospholipids and cholesterol. In skeletal muscle cells it stores calcium ions. Within some endocrine gland it contains enzymes that detoxify harmful substances

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

What is the structure of the mitochondria?

A

Oval shaped with two membranes. The inner membrane is very folded, which forms finger like structures called cristae - increase surface area. The matrix is formed from the folding of the inner cell membrane and contains some of the enzymes involved in aerobic respiration

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

What is the function of the mitochondria?

A

Site of aerobic respiration to produce adenosine triphosphate (ATP)

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

What is the structure of the Golgi?

A

Formed of a Golgi apparatus and several small vesicles. Golgi apparatus is membrane bound and channel-like and filled with fluid. The vesicles are detached fluid filled pockets found at the edges

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

What is the function of the Golgi?

A

Processing and packaging lipids and proteins. Produces lysosomes. The lipids and proteins formed are stored in the vesicles which can transport them out of the cell through the cell membrane

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

What is the structure of a lysosome?

A

Type of Golgi vesicle with no obvious internal structure. Has a membrane and contains digestive enzymes called lysozymes. The pH is acidic in contrast to the alkali pH of the cytoplasm

26
Q

What is the function of the lysosomes?

A

Digesting invading cells old and unwanted parts of cells and complex biomolecules. The membrane ensures the lysozymes are kept separate from the cytoplasm to prevent self digestion

27
Q

What is the structure of a chloroplast?

A

Double membrane that surrounds a gel like stroma. Within the stroma are fluid filled sacs called thylakoids which are stacked to form grana (granum sg). Thylakoid membranes (lamellae) link the grana together. Thylakoid membranes contain photosynthetic pigments that absorb light energy

28
Q

What is the function of the chloroplasts?

A

Site of photosynthesis. Light-dependent reactions occur in the thylakoid membranes, light-independent reactions take place within the stroma

29
Q

What is the structure of the cell wall?

A

Rufus structure. In plants and algae it’s made of cellulose, in fungal cells it’s made of chitin

30
Q

What’s the function of the cell wall?

A

Help maintain cell shape and protect cell from pathogens

31
Q

What is the structure of the permanent vacuole?

A

Permanent pockets of cell sap (solution of sugars, salts, and water) surrounded by a membrane came the tonoplast

32
Q

What’s every function of the permanent vacuole?

A

Maintains osmotic pressure, stores unwanted chemicals that have been discarded from the cell

33
Q

How big are viruses?

A

0.02-0.3 micrometres

34
Q

What type of particles are viruses?

A

Non-cellular

35
Q

What are viruses made of?

A

Genetic material and protein

36
Q

How do antiviral mediations work?

A

But preventing the viruses from replicating

37
Q

How do viruses enter cells?

A

Endocytosis, a vector or some inject their genetic material into the host cell

38
Q

Are viruses living or non-living?

A

Non-living

39
Q

Why are viruses not considered as living?

A

Not cells, don’t grow our respond to their surroundings, can’t make food/take in food, don’t produce waste, lack a metabolism of their own

40
Q

What are the ways of classifying viruses?

A

The type of nucleic acid the contain (DNA or RNA) or they are enveloped our non-enveloped (enveloped have a lining)

41
Q

What is the structure of a virus?

A

All have a protein coat (capsid) and a core (nucleic acid). Some have a protective membrane. Vary in shape, most have a specific host.

42
Q

What do the capsids of viruses do?

A

Protect the nucleic acid

43
Q

What does the virus’s capomere do?

A

Contains genes that allow the virus to transfer its nucleic acid into the host cell

44
Q

What do the tails and spikes off a virus do?

A

Helps the virus attach to the host

45
Q

Name four different viruses.

A

Lambda phage, tobacco mosaic, Ebola, HIV

46
Q

What kind of nucleic acid does lambda phage contain?

A

DNA

47
Q

What type of nucleic acid does tobacco mosaic contain?

A

RNA

48
Q

What type of nucleic acid does Ebola contain?

A

RNA

49
Q

What type of nucleic acid does HIV contain?

A

RNA

50
Q

What type of genetic replication does lambda phage use?

A

DNA transcribed to RNA

51
Q

What type of genetic replication does tobacco mosaic use?

A

RNA copied into mRNA

52
Q

What type of genetic replication does Ebola use?

A

RNA copied to mRNA

53
Q

What type of genetic replication does HIV use?

A

uses reverse transcriptase to make double stranded DNA which is incorporated into host DNA

54
Q

What are the hosts of lambda phage?

A

Bacteria

55
Q

What are the hosts of tobacco mosaic?

A

Tobacco plants

56
Q

What are the hosts of Ebola?

A

Humans and some animals

57
Q

What are the hosts of HIV?

A

Humans

58
Q

What is a key feature of lambda phage?

A

No envelope

59
Q

What is a key feature of tobacco mosaic?

A

Spiral copsid, no envelope

60
Q

What is a key feature of Ebola?

A

No envelope

61
Q

What is a key feature of HIV?

A

Sphericalcapsid, envelope retrovirus

62
Q

Describe the steps to the lytic cycle?

A
  1. Virus lands on cells and attaches to cell receptor
  2. Virus enzyme weakens cell membrane and the genetic material enters the host cell
  3. Virus DNA/RNA replicates and uses ribosomes to make virus proteind
  4. New virus parts are assembled in the cytoplasm
  5. Virus enzyme causes cell membrane to lyse, new viruses are released to find new host.
    The cycle repeats

Biology A Level (2 decks)

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