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Biology Miss Negus > Cell Structure > Flashcards

Cell Structure Flashcards

1
Q

What is magnification?

A

The number of times larger an image appears compared to the size of the object

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2
Q

What is resolution?

A

The clarity of an image, the higher the resolution the clearer the image. How well a microscope distinguishes between 2 points that are close together

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3
Q

What is light/optical microscope?

A

~It has limited resolution (0.2lrm)
~It has a magnification of up to x1500
~Used in schools, colleges, hospitals and research labs
~Can show cell structure like living things but it has limited resolution

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4
Q

What is a laser scanning microscope?

A

~Has a high resolution
~Magnification varies
~Can focus on structures at different depths of a specimen
~Used in medical profession
~Has 3D image
~uses laser beams to scan a specimen usually tagged with fluorescent dye which gives off light

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5
Q

What is a transmission electron microscope?

A

~Has a very high resolution (0.0002lrm)
~Has a magnification of up to x2million (soon 50 million)
~It gives a clear image but has a black and white, 2D image only
~Specimen has be dehydrated and fixed before it is used so can’t be used to look at further after and kills living things
~Only used on thin specimens

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6
Q

What is a scanning electron microscope?

A

~Has a very high resolution (0.002lrm)
~Has a magnification of x200000
~The electrons bounce of the specimen and focus on a screen which gives a 3D image
~The image is black and white but can add colour via computer

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7
Q

What to do before viewing a sample under a optical microscope?

A

~Stain it with dyes like iodine solution
~Take thin slices of the sample like embedding it in wax to get thin slices
~Drug the sample e.g. ethanol

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8
Q

What are the different types of drawings?

A

~Low power plan

~High power drawing

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9
Q

How to draw a low power plan:

A

~only draw areas of cells/tissue

~never individual cells

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10
Q

Hope to draw a high power drawing:

A

~draw individual cells include all details

~include all details

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11
Q

What is the structure of the nucleus?

A

~double cell membrane with pores in the envelope
~mostly spherical, dense contains nucleoplasm
~contains chromatin fibres and DNA

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12
Q

What is the function of the nucleus?

A

~makes ribosomes and stores it
~makes RNA and protein and store it
~controls and regulates cell activities, metabolic and chemical
~controls genetic information of the cell and characteristics
~controls protein and enzyme synthesis
~key role in cellular reproduction

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13
Q

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

A

~system of membranes, containing fluid filled cavities called cistern are
~coated with ribosomes

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14
Q

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

A
  • covered with ribosomes

- folds and processes proteins that have been made at the ribosomes

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15
Q

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

A

~consists primarily of cisternae

~vesicles are round sacs

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16
Q

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

A
  • no ribosomes

- it synthesises and processes lipids

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17
Q

What is the structure of the golgi apparatus?

A

~consists of a stack of membrane-bound flattened sacs

~secretory vesicles bring materials to and from the Golgi

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18
Q

What is the function of the Golgi apparatus?

A

~processes and package proteins and lipid molecules
~proteins are modified
~proteins are packaged into vesicles that are pinched off and then stored or move into the plasma membrane to be used in or exported outside the cell
~makes lysosomes
~sort, pack and transport molecules around the cell

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19
Q

What is the structure of mitochondria?

A

~may be spherical, rod-shaped or branches and are 2-5 micrometers long
~surrounded by 2 membranes with a fluid filled space between them. The inner membrane is highly folded into cristae
~inner part of the mitochondrial is a fluid-filled matrix

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20
Q

What is the function of mitochondria?

A

~site of ATP (energy currency) production during aerobic respiration
-site of aerobic respiration

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21
Q

How do you calibrate a lens?

A
  1. ) select 10x lens

2. ) place the stage graticle on the microscopes stage and turn the eyepiece until the two scales are parallel

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22
Q

Conversions:

A

m—>cm (x100) nm—>lrm (/1000)
cm—>mm (x10) lrm—>mm (/1000)
mm—>lrm (x1000) mm—>cm (/10)
lrm—>nm (x1000) cm—>m (/100)

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23
Q

What is the formula for magnification?

A

magnification= image size/ actual size

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24
Q

How do you find the total magnification?

A

Multiply the magnification for the eyepiece lens and the objective lens

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25
Q

How do you workout the value of each eye graticle division?

A

Length of stage graticle / number of divisions on eye graticle

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26
Q

What is the structure of cytoskeleton?

A

~network of proteins structure in the cytoplasm
~rod-like microfilaments
~straight, cylindrical microtubules made of tubulin

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27
Q

What is the function of cytoskeleton?

A
  • supports the cells organelles
  • strengthen the cell and maintain its shape
  • responsible of movement of materials within the cell
  • proteins of the cytoskeleton can cause the cell to move e.g. flagella
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28
Q

What is the structure of lysosomes?

A

~small bags formed from the Golgi. Each surrounded by a smaller membrane
~contain powerful hydrolytic (digestive) enzymes
~abundant in phagocytes cells e.g. neutrophils and macrophages (white blood cell type) that can ingest and digest invading pathogens e.g. bacteria

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29
Q

What is the function of lysosomes?

A

~keep digestive enzymes separate from the rest of the cells which digest invading cells/ break down worn out components of the cell

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30
Q

What is the structure of the vacuole?

A

~largest organelles found in a cell
~store water, nutrients, and waste before the cell deposits of it
~surrounded by a thin membrane filled with fluid and molecules they take it
~when multiple vesicles together it forms 1 big vacuole

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31
Q

What is the function of the vacuole?

A

~maintains cell stability

~contains cell sap

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32
Q

What is the structure of the chloroplasts?

A

~large organelles 4-10 micrometers long
~surrounded by a double membrane or envelope
~inner membrane is continuos with stacks of flattened membrane sacs (thylakois contain chlorophyll). Each stack of them is called a granyl. The fluid filled matrix is the atom
~contain loops of DNA and starch grains

33
Q

What is the function of chloroplasts?

A

~found in plant cells and in some protoctists
~site of photosynthesis
~in the grana, light energy is trapped by chlorophyll and used to make ATP

34
Q

What is the structure of cilia and undulipodia?

A

~protrusions from the cell and surrounded by the cell surface membrane
~each contain microtubules
~formed form centrioles
~hair-like

35
Q

What is the function of cilia and flagellum?

A

~cilia moves substances along the cell surface

~undulipodium enables cells to move forward

36
Q

What is the structure of centrioles?

A

~2 bundles of microtubules at right angles to each other made of tubulin protein subunits arranged to form a cylinder

37
Q

What is the function of centrioles?

A

Involved in the separation of chromosomes during cell division

38
Q

What is the structure of cellulose cell wall?

A

~cellulose fibres are long and linear polymers of hundreds of glucose molecules
~made from bundles of cellulose fibres
~polysaccharide
~found on the outside of a cell surrounding all the organelles

39
Q

What is the function of cellulose cell wall?

A

~provide mechanical strength to the cell (prevents it from bursting)
~controls the direction of cell growth
~permeable
~maintains cell shape

40
Q

What is the structure of ribosomes?

A

~small spherical organelles, about 20 micrometers in diameter
~made of ribosomal RNA
~made in the nucleolus as 2 separate subunits, which pass through the nuclear envelope into the cell cytoplasm and then combine
~some remain free in the cytoplasm and some watch to the RER

41
Q

What is the function of the ribosomes?

A

~ones that are bound to the RER are mainly for synthesising proteins to be exported out of the cell
~ones that are free in the cytoplasm, either singly or in clusters are primarily the site of assembly of proteins that will be used inside the cell

42
Q

What are similarities of eukaryotic and prokaryotic cells?

A

~a plasma membrane cytoplasm
~ribosomes for assembling amino acids into proteins
~DNA and RNA

43
Q

What are the differences of eukaryotic and prokaryotic cells?

A

~prokaryotic are much smaller
~prokaryotic have a much less well-developed cytoskeleton with no centrioles
~prokaryotic don’t have a nucleus
~prokaryotic don’t have a membrane-bound organelles e.g. mitochondria, RER, chloroplast, Golgi apparatus
~prokaryotic have a wall made of polysaccharide and notcellulose like eukaryotic
~prokaryotic have smaller ribosome
~prokaryotic have naked DNA (plasmids) not linear chromosomes

44
Q

What are some things that some prokaryotic cells have?

A

~a protective waxy capsule surrounding their cell wall
~small loops of DNA, called plasmids, as well as the main large loop of DNA
~flagella- long whip-like projections which enable them to move
~pili- small hair-like projections that enable the bacteria to adhere to host cells or to each other and allow the passage of plasmid DNA for 1 cell to another

45
Q

How do prokaryotic cells divide?

A

By binary fission as they don’t have linear chromosomes so they can’t carry out mitosis. Before they divide, their DNA is copied so that each new cell receives the large loop of DNA and any smaller plasmids

46
Q

What are basophils?

A

Cells that play a part in ‘immune surveillance’ so they detect and destroy some early cancer cells. They are loaded with granules which can be released by inflammator, infectious or allergic triggers

47
Q

What are neutrophils?

A

A type of white blood cell that engulfs foreign matter and traps it in a large vacuole (phagosome), which fuses with lysosomes to digest foreign matter

48
Q

What are lymphocytes?

A

Cells that circulate in your blood that are part of the immune system can destroy or latch on viruses or bacteria

49
Q

What are thrombocytes and what is their function?

A

Platelets and they help form blood clots to slow or stop bleeding and to help wounds heal

50
Q

What are erythrocytes and what is their function?

A

Red blood cells and they carry oxygen from the lungs to the body tissues

51
Q

What is the function of the nucleolus?

A

Makes ribosomes

52
Q

What is the function of the plasma membrane?

A
  • regulates movement of substances in and out of the cell
  • can respond to chemicals from receptor molecules
  • site of cell communication
53
Q

What happens to proteins which are made from ribosomes on the RER?

A
  • They are folded and processed in the RER
  • Then they are transported to the Golgi apparatus in vesicles
  • At the Golgi apparatus the proteins undergo further processing
  • They then enter more vesicles to be transported around the cell
  • They are excreted or attached to the cell membrane
54
Q

What happens to proteins which are created by ribosomes in the cytoplasm?

A

They stay in the cytoplasm

55
Q

What is the magnification equation?

A

magnification=image size
——————
actual size

56
Q

Why are specimens stained?

A
  • Sometimes the object being viewed is completely transparent so light just passes through it.
  • Stains are taken up by some parts of the object more thank others and the contrast makes the different parts show up
  • Different stains are used to make different things show up
57
Q

What are some common stains?

A

Methylene blue and eosin

58
Q

How to prepare a microscope slide?

A

•Dry mount
- taking a thin slice of the specimen to use on the slide
-put the specimen on the middle of the slide with tweezers
-put a cover slip on top
•Wet mount
-put a small drop of water onto the slide then place the specimen on it with tweezers
-put the cover slip upright on the slide and tilt it carefully to cover the specimens without any air bubbles
-then add a stain

59
Q

How to use a light microscope?

A
  • Place the slide with the specimen on the stage
  • Select lowest powered objective lens
  • Adjust the stage with the knob
  • Look into the eyepiece
  • Adjust the stage until the image is clear
  • Can change the magnification
60
Q

What are stage micrometers used for?

A

It is a microcode slide with an accurate scale and is used to work out the value of the divisions on the eyepiece gear curl at a particular magnification

61
Q

What could be used as evidence of the endosymbiotic theory?

A
  • mitochondria contain ribosomes that are smaller than those found in the cell cytoplasm
  • mitochondria are a similar size to bacteria
  • chloroplasts have their own circular DNA
62
Q

What is the endosymbiotic theory?

A

The theory that suggest that the mitochondria and chloroplasts found in eukaryotic cells represent formerly free-living bacteria that were absorbed into a larger cell

63
Q

What is a structure present in animals cells that is not present in plant cells?

A

Centrioles

64
Q

How do the organelles in cells work together to procure and release protein molecules from the cell?

A
  • the nucleus contains genes for protein and is the site of transcription
  • the ribosomes on the rough endoplasmic reticulum are the site of protein synthesis
  • the vesicles then transport the proteins
  • the Golgi apparatus then processes and packages the proteins
  • the vesicles then fuse to the cell surface membrane to be transported out of the cell
65
Q

What is the process called where root epidermal cells absorb minerals from the soil and how they are specialised to achieve absorption?

A

The process is active transport

  • the cells have, extensions/hairs
  • thin cell wall
  • large surface area
  • many mitochondria
  • carrier proteins in cell surface membrane
66
Q

What is the max magnification of a light microscope?

A

X1500

67
Q

What is the max magnification of a scanning electron microscope?

A

X200,000

68
Q

What is the max magnification of a transmission electron microscope?

A

X2,000,000

69
Q

What is the max resolution of a light microscope?

A

0.2 micrometers

70
Q

What is the max resolution of a scanning electron microscope?

A

0.001 micrometres

71
Q

What is the max resolution of a transmission electron microscope?

A

0.0001 micrometres

72
Q

How does a laser scanning confocal microscope work?

A

It uses laser beams to scan a specimen usually tagged with fluorescent dye. The taser causes dye to give off light. It has a computer generated 3D image.
Can look at objects at different depths in thick specimens

73
Q

How does a transmission electron microscope work?

A

Uses electron magnets to focus a beam of electrons, which is transmitted through the specimen
Only used on thin specimens

74
Q

How does a scanning electron microscope work?

A

Scan a beam of electrons across the specimens, knocking off electrons from the specimen which tether in a tube forming an image which can be 3D. It shows the surface of the specimen

75
Q

What is a eukaryotic cell?

A

Animal and plant cell

76
Q

What is a prokaryotic cell?

A

Bacteria cell

77
Q

How to add a stain to a wet mount slide?

A

Put a drop of stain next to one edge of the cover slip and a piece of paper towel next to the opposite edge. The paper towel will draw the stain under the slip, across the specimen

78
Q

What is the arrangement of microtubules in a flagellum?

A

It has an outer ring of microtubule pairs with 2 in the middle

79
Q

What is the function of centrioles?

A

Involved in the separation of chromosomes during cell division

Biology Miss Negus (4 decks)

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