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Biology > 2.1 - Microscopy and Cell structure > Flashcards

2.1 - Microscopy and Cell structure Flashcards

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1
Q

What are the pros of a light microscope?

A

Cheap, portable, easy to use, can study living specimens

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2
Q

What are the cons of a light microscope?

A

Limited magnification, poor resolution

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3
Q

What is a laser scanning confocal microscope used for?

A

Use laser light to scan an object point by point ceating a high resolution, different depths of the specimen

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4
Q

What is a transmission electron microscope (TEM) be used for?

A

Observing the internal ultrastructure of cells under high magnification and resolution

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5
Q

What is an eye piece graticule?

A

A small ruler fitted to a light microscope’s eyepiece. It must be calibrated using a stage micrometer before being used to measure specimens.

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6
Q

What is a scanning electron microscope used for?

A

Viewing the surface of objets under high magnification and resolution

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7
Q

What are the pros of an electron microscope?

A

Very high magnification and excellent resolution

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8
Q

What are the cons of an electron microscope?

A

specimen has to be dead, very expensive, very large, needs great skill and training to use

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9
Q

Why do we stain specimens?

A

To provide more contrast, and make it easier to distinguish certain parts (intracellular organelles)

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10
Q

What is the formula to calculate magnification?

A

Magnification = Image size / Actual size

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11
Q

What is magnification?

A

A measure of how much larger the image of a specimen looks under the microscope relative to its actual size

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12
Q

What is resolution?

A

The ability to distinguish between to adjacent individual points as separate

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13
Q

What are the maximum resolutions of the different microscopes?

A

Light: 200nm/0.2micrometres
SEM: 10nm
TEM: 0.2nm

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14
Q

What is the maximum magnification of the different microscopes?

A

Light: 1,500x SEM: 100,000x TEM: 500,000x

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15
Q

What are the main structures of all eukaryotic cells? (10)

A

Nucleus, nucleolus, cytoplasm, cytoskeleton, plasma membrane, mitochondria, Golgi apparatus, smooth endoplasmic reticulum, rough endoplasmic reticulum, ribosomes

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16
Q

What is the structure and function of the nucleus?

A

Structure: Surrounded by a double membrane with gaps called nuclear pores (the nuclear envelope), Contains chromatin (DNA wound around histones)
Function: Stores the human genome, controls the cell by providing instructions for protein synthesis.

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17
Q

What is the structure and function of the nuclear envelope?

A

Structure: A double membrane embeded with channel proteins forming pores.
Function: Separates the nucleus from the rest of the cell, Pores allow ribosomes and mRNA to leave the nucleus.

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18
Q

What is the structure and function of the rough endoplasmic reticulum (RER)?

A

Structure: A system of fluid filled membranes called cisternae studded (Embedded) with ribosomes, continuous with the nuclear membrane
Function: Large surface area formed by folding, enables lots of protein synthesis. Proteins are pinched off in vesicles transported to the Golgi apparatus

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19
Q

What is the structure and function of the smooth endoplasmic reticulum (SER)?

A

Structure: A system of fluid filled membranes. No ribosomes
Function: Contain enzymes for cholesterol, lipid, steroid and phospholipid synthesis

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20
Q

What is the structure and function of the Golgi apparatus?

A

Structure: A stack of flattened membrane bound sacs.
Function: Vesicles from the RER join the sis face of the Golgi apparatus and they move through the Golgi body where they are modified, by adding sugar to make glycoproteins or adding lipids to form glycolipids. The Golgi then folds proteins into their 3D shape. Modified proteins are pinched off from the trans face into transport vesicles where they are sent to outside the cell, the mitochondria or to another organelle

21
Q

What is the structure and function of the ribosomes?

A

Structure: 2 subunits, large and small, Made of rRNA
Function: Proteins synthesis

22
Q

What is the structure and function of the mitochondria?

A

Structure: Double membrane bound, inner membrane folded into cristae (Where oxidative phosphorylation occurs to use up O2 and generate ATP) within a fluid filled matrix (Where the Kreb cycle occurs to produce CO2). Contain own DNA and 70s ribosomes
Function: Site of aerobic respiration

23
Q

What is the structure and function of the lysosomes?

A

Structure: Membrane bound sacs containing hydrolytic (digestive) enzymes
Function: Breaking down old organelles and foreign matter for reuse or, in lymphocytes the lysosomes are responsible for digesting any bacteria that is taken in by phagocytosis

24
Q

What is the structure and function of the chloroplasts?

A

Structure: Double membrane bound, inner membrane forms flat discs filled with chlorophyll called thylakoids (Where the light-dependent stage occurs, using chlorophyll), in stacks called granum that are connected to each other by intergranal lamellae. These are surrounded by a fluid matrix called the stroma (Where the light-independent stage occurs). Contain own DNA and 70s ribosomes.
Function: Site of photosynthesis.

25
Q

What is the structure and function of the plasma membrane?

A

Structure: Phospholipid bilayer, cholesterol, proteins, glycoproteins, glycolipids.
Function: Separates cell contents from external environment. Controls what enters and leaves the cell. Acts as a receptor for various chemicals. site of chemical reactions.

26
Q

What is the structure and function of the centrioles?

A

(Present in animals only)
Structure: Two bundles of microtubules at right angles.
Function: Used as an anchor point to separate chromosomes during cell division. Form the basis of cilia.

27
Q

What is the structure and function of the cell wall?

A

(Present in plants and fungi only)
Structure:
-Bundles of cellulose fibres in plants, the cellulose microfibrils build up into macrofibrils which are cross-hatched and layered on top of each other to make the cell wall more impermeable
-The cell wall is made of chitin in fungi
Function:
-Provides structural support and strength, maintaining the cell’s shape and resists bursting due to turgor pressure from the vacuole, preventing the cell from bursting when turgid
-The cell wall is also semi-permeable to allow solutions through

28
Q

What is the structure and function of the flagella?

A

Structure: 9 pairs of microtubules surround 2 lone microtubules. A membrane covers the whole thing.
Function: Used for moving unicellular organisms around.

29
Q

What is the structure and function of the cillia?

A

Structure: -9 pairs of microtubules surround 2 lone microtubules -Present in great numbers.
Function: move together to waft fluids and
Pathogens such as mucus

30
Q

Which structures are involved in the production of proteins?

A

Nucleus, RER, transport vesicle, Golgi apparatus

31
Q

What is the structure and function of the cytoskeleton?

A

Structure & functions: Microfilaments made of actin - Allows cell movement and cytokinesis. Microtubules made of tubulins scaffold like structures - Give cell shape. Intermediate fibres - mechanical strength, maintaining integrity.

32
Q

What do prokaryotic and eukaryotic cells have in common?

A

Plasma membrane, cytoplasm, ribosomes, DNa and RNA

33
Q

What is different between prokaryotic and eukaryotic cells?

A

Prokaryotes have no: Nucleus, centrioles, membrane bound organelles (Mitochondria, chloroplast, RER, SER, Golgi apparatus)
Prokaryotes also have: peptidoglycan cell walls, smaller 70s ribosomes, naked loop of DNA called a plasmid, cell walls made of peptidoglycan, flagella for movements, a waxy protective cuticle layer to protect bacteria from medicine and pili

34
Q

How do prokaryotes divide?

A

Binary fission

35
Q

Which proteins are fibrous?

A

Collagen
Elastin
Keratin

36
Q

Which proteins are globular?

A

Haemoglobin
Insulin
Catalase

37
Q

What are the sizes of different organelles/biological matters that are used to show the progression of scale?

A 
[Seen by electron microscope] ↓
-Atom: 0.1nm
-Phospholipid: 3.5nm
-Phospholipid bilayer: 7nm
-Ribosome: 10nm
-Flu virus: 100nm
[Seen by light microscope] ↓
-Mitochondria, chloroplasts and prokaryotic cells: 1micrometre
-Human cheek cells: 10micrometres
[Seen by human eye] ↓
-Human egg cells: 100micrometres
-Onion epidermis cell: 200micrometres
-Amoeba: 1mm
-Chicken egg: 5cm
38
Q

What are the sizes of each unit relative to a meter?

A
  • 1nm = 1 x 10^-9
  • 1micrometre = 1 x 10^-6
  • 1mm = 1 x 10^-3
  • 1cm = 1x10^2
39
Q

How many nanometres are there in a micrometre?

A

-There are 1000 nanometres in 1 micrometre

40
Q

How many micrometres are there in a millimetre?

A

-There are 1000 micrometres in 1 millimetre

41
Q

How many nanometres are there in 0.2micrometres

A

-There are 200 nanometres in 0.2 micrometres

42
Q

What organelles are present in plant cells but not animal cells?

A
  • Cell well
  • Vacuole
  • Chloroplast
43
Q

What is the function of the amyloplast?

A

The amyloplast stores starch

44
Q

What is the function of the vacuole?

A
  • Stores cell sap

- Maintains the shape and the structure of a cell as it regulates osmosis and the turgidity

45
Q

Why do antibiotics sometimes target peptidoglycan?

A
  • Antibiotics sometimes work to synthesise and destroy peptidoglycan because only prokaryotes contain peptidoglycan in their cell walls
  • This means, by destroying peptidoglycan it causes prokaryotic cells such as bacteria to be destroyed
46
Q

What are pili?

A
  • Hair-like structures that can be involved with allowing bacteria to lock together in a colony
  • Pili is also responsible to transfer genes from one bacteria to another through horizontal gene transfer
47
Q

If a nucleus has an actual size of 3micrometres and an image size of 22mm what is the magnification of the image?

A 
M = I/A
A = 3micrometres
I = 22mm (22,000micrometres)
M = 22,000/3
M = 7,333x
48
Q

What is the process of the production of a protein in a eukaryotic cell?

A
  • The gene is transcribed into mRNA
  • The mRNA exits the nucleus via the nuclear pore into the cytoplasm
  • mRNA binds to the ribosome and translation occurs, the code on the mRNA is translated into a sequence of amino acids which form a polypeptide chain
  • The protein is then pinched off from the cisternae of the RER to form a transport vesicle
  • The transport vesicle enters the sis face of the Golgi
  • The protein is modified in the Golgi, carbohydrates/lipids could be added and the protein would be folded into a 3D structure
  • The protein exits the trans face of the Golgi and it enters a secretory vesicle
  • The secretory vesicle is targeted for the cell surface membrane
  • The secretory vesicle fuses with the cell surface membrane
  • The protein is released out the cell via exocytosis

Biology (23 decks)

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