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BIOLOGY REVISION > Cell structure > Flashcards

Cell structure Flashcards

1
Q

What is magnification?

A

Magnification is how much bigger an image appears compared with the original object. Magnification produced by microscopes is LINEAR

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2
Q

What is resolution?

A

Resolution is the ability of an optical instrument to see or produce an image that shows fine detail

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3
Q

How do you calculate total magnification?

A

Total magnification = eye piece magnification x objective lens magnification

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4
Q

How do you calculate image size? What is the equation triangle?

A

Image = Actual size x magnification
I
A M

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5
Q

What is a optical microscopes resolution and magnification?

A

Optical microscopes = x1500 and resolution of 200nm (cant distinguish objects closer than this)

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6
Q

What are the advantages and disadvantages of optical microscopes?

A

Optical microscopes advantages:
Cheap, easy to use, portable, can study whole live specimens
Disadvantages:
Low resolution and magnification

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7
Q

What is the resolution of electron microscopes?

A

Electron microscopes have a wavelength of 0.004nm

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8
Q

Discuss transmission electron microscopes

A

Transmission electron microscopes chemically fix their specimens (dehydrate and stain). Electrons [ass through the specimen. They have a magnification of 2-50 million times

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9
Q

What image to transmission electron microscopes produce?

A

Transmission electron microscopes produce a 2D black and white image called an electron micrograph

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10
Q

What type of image does a scanning electron microscope produce?

A

Scanning electron microscopes produce a black and white 3D image

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11
Q

How do scanning ekecetron microscopes work?

A

Scanning electron microscopes use electrons that bounce off the specimen after it has been fixed and covered in a film of metal. This occurs in a vacuum.

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12
Q

How do laser scnanning microsopes work and whatvare their advantages?

A

laser scanning microscopes (confocal) scan the objects point by point. The advantages are:
High resolution and contrast image, theyhave depth electivity and so can study whole live specimens

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13
Q

How would you study a live specimen?

A

Studying a live specimen:

  • School light microscope and adjust the iris diaphragm to reduce illumination of specimen.
  • use light interference and a dark background to observe them
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14
Q

How do you prepare a slide?

A

Preparing slides:

  1. dehydrate
  2. embed in wax
  3. slice sections
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15
Q

What are 5 stains and what do they show?

A

Stains:

  • Methyline blue - general
  • acetic orsein- DNA stained red
  • Eosin- stains cytoplasm pink
  • sudan red- stains lipids
  • iodine- cell walls yellow and starch blue
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16
Q

What is the scale used for microscopes?

A

The scale used is logarithmic meaning it goes up in steps where there is a 10 fold increase

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17
Q

what organisms are eukaryotic?

A

Animal cells, plant cells, fungi cells and protoctista are all examples of eukaryotic cells

18
Q

What are some similarities between animals and plant cells?

A

Similarities between animal and plant:

Nucleus, nucleolus, ribosomes, mitochondria, endoplasmic reticulum Golgi, plasma membrane, vesicles

19
Q

Where are some differences between animal and plant cells?

A

Differences between animal and plant:

  • Plants have vacuole
  • plants have chloroplasts
  • plants have amyloplasts containing starch
  • plants have a cell wall
20
Q

What is the structures and functions of nucleus?

A

Nucleus:

  • nuclear envelope with pores, chromatin, nucleolus
  • stores genetic information, provides instructions for protein synthesis
21
Q

What is the definition of chromatin?

A

Chromatin- DNA packaged with histone proteins

22
Q

What is the structure and functions of Rough ER

A

Rough ER:

  • Cisternae provide large surface area for ribosomes
  • ribosomes for protein synthesis
23
Q

What is the structure and functions of smooth ER

A

Smooth ER:

  • cisternae
  • lipid metabolism, synthesis of cholesterol steroid hormones lipids and phospholipids and absorption and transport of lipids
24
Q

What is Golgi structure and function?

A

Golgi:

  • Near vesicles , membrane bound flattened sacs
  • protein modification (adding sugars or lipids), folding of proteins and packaging into vesicles for storage or movement
25
Q

What is mitochondria structure and functions?

A

Mitochondria:

  • Double membrane, cristae, matrix and 2-5 micrometres big
  • ATP production, self replicate
  • more abundant in active cells
26
Q

What are the features and function of lysosomes?

A

Lysosomes:

  • Contain hydrolytic enzymes, abundant in phagocytic cells
  • Compartmentalise enzymes from the rest if the cell to prevent damage, recycle
  • formed from the golgi
27
Q

What is the structure of chloroplasts?

A

Chloroplast structure:

  • stroma
  • grana made up of thylakoids
  • intergranal lamellae
  • double membrane
  • loops of DNA
  • starch grains
28
Q

What is the function of chloroplasts?

A

Chloroplasts are responsible for photosynthesis

29
Q

What is the structure and function of vacuoles?

A

Vacuoles:

  • membrane called a tonoplast, contains fluid
  • maintain turgidity and therefore support plant structure
30
Q

What si the structure and function of cilia and undolipodia?

A

Cilia and Undolipodia:

  • contain microtubules and formed from the centrioles
  • Move mucus, receptors and movement of sperm
31
Q

Structure and function of ribosomes

A

Ribosomes

  • made of rRNA in the nucleolus
  • free floating ribosomes synthesise proteins used in the cell
  • ribosomes bound to RER synthesise proteins exported out of the cell
32
Q

Structure and function of centrioles

A

centrioles:

  • 2 bundles of microtubules arranged at 90 degrees, made of tubulin and the subunits are arranged to form a hollow cylinder
  • form the mitotic spindle and cilia and undulipodia
33
Q

Structure and function of cell wall

A

Cell wall:

  • Bundles of cellulose in plants
  • chitin in fungi
  • prevents cell from bursting, gives strength and support and is permeable
34
Q

Structure of the cytoskeleton

A

Cytoskeleton structure:
it is a network of protein structures within the cytoplasm
-microtubules made of tubulin (transport, mitotic spindle, cilia and undulipodia)
-microfilaments made of actin (support and strength)
-intermediate filaments made of proteins (anchor the nucleus and aid in cell to cell communication)

35
Q

What are the steps for making and secreting a protein?

A

Making and secreting a protein:

  1. gene is transcribed into mRNA which passes out of nuclear envelope via pores to ribosomes
  2. mRNA translated into a protein and the protein gets assembled
  3. the molecules of protein pass to cisternae of RER and vesicles then pinch off
  4. vesivles move alone microtubules by motor proteins to Golgi
  5. proteins modified at Golgi from cis— trans end and vesicles pinch off and move to plasma membrane
  6. vesicles fuse and protein is released out of the cell by exocytosis
36
Q

What are similarities of prokaryotic and eukaryotic cells?

A

Similarities between prok and euk:

  • plasma membrane
  • cytoplasm
  • ribosomes
  • DNA and RNA
37
Q

What are differences between prokaryotic and eukaryotic cells?

A

Differences between prok and euk:

  • Euk ribosomes are 80S—–prok are 70 S
  • Prok have cell wall of peptidoglycan/miurein
  • prok are smaller
  • euk have well developed cytoskeleton + centrioles and prok have no centrioles
  • prok have no membrane bound organelles
  • euk have nucleus with DNA and prok have naked loop of DNA
  • prok divide by binaery fission—- euk divide by mitosis
38
Q

What are some features of prokaryotic cells that are absent in eukaryotic cells?

A

Prokaryotic cells features:

  • protective waxy capsule
  • plasmids
  • pili (act as passage for plasmid dna to move from plasmid to plasmid)
  • flagella
39
Q

Why could prokaryotic cells and mitochondria be looked at similarly?

A

Mitochondria are thought to be derived from prokaryotic cells as they share similar features. e.g. loops of DNA. (chloroplasts also share these)

40
Q

What is the theory of how eukaryotic cells arose from prokaryotic cells called?

A

The theory of how eukaryotic cells arose from prokaryotic cells is called the endosymbiont theory.

41
Q

Describe viruses

A

Viruses are acellular non living particles.

  • 20-300 nm big
  • contain nucleic acids
  • have a capsid (protein coat)

BIOLOGY REVISION (21 decks)

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