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A Level Biology > Topic 2.1 Eukaryotic cells > Flashcards

Topic 2.1 Eukaryotic cells Flashcards

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1
Q

Define a tissue

A

a group of specialised cells carrying out a particular bodily function

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2
Q

Define an organ

A

a structure made up of several different types of tissues grouped together to carry out a particular function for the body

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3
Q

Define an organ system

A

a group of organs working together to carry out a particular functions in the body

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4
Q

What are epithelial tissues?

A

tissues that from the lining of surfaces inside and outside the body

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5
Q

What are the 4 main types of tissue in the body?

A
  • epithelial tissue
  • muscle tissue
  • connective tissue
  • nervous tissue
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6
Q

Which type of epithelial cells usually line blood vessel surfaces and the walls of alveoli and capillaries?

A

squamous epithelium

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7
Q

What is a light microscope?

A

a tool that uses a beam of light and optical lenses to magnify specimens up to 1500x life size

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8
Q

What is an electron microscope?

A

a tool that uses a beam of electrons and magnetic lenses to magnify specimens up to 500 000 x life size

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9
Q

Define magnification

A

a measure of how much bigger the image you see is than the real object

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10
Q

Define resolution

A

a measure of how close together 2 objects can be before they are seen as one

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11
Q

What is a transmission electron micrograph (TEM)?

A

micrographs produced by the electron microscope that gives 2D images like those from a light microscope, but magnified up to 500 000 X

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12
Q

What is a scanning electron micrograph (SEM)?

A

micrographs produced by the electron microscope that have a lower magnification than the TEMs, but produce a 3D image

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13
Q

Give the equation for total magnification

A

total magnification= magnification of objective lens x magnification of eyepiece lens

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14
Q

State the advantages of a light microscope

A
  • can see living organisms or parts of them, useful as it allows you to compare prepared slides with living tissue
  • relatively cheap so available in schools, unis, hospitals and industrial labs and research labs
  • light and portable
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15
Q

State the disadvantages of a light microscope

A
  • preservation and staining tissue can produce artefacts in the tissues being observed
  • limited powers of resolution and magnification
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16
Q

State the advantages of an electron microscope

A

-huge powers of magnification + resolution

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17
Q

State the disadvantages of an electron microscope

A
  • all specimens examined in a vacuum so can’t see living material
  • specimens undergo treatment resulting in artefacts
  • preparation is very skilled work
  • extremely expensive
  • large and has to be kept under constant temperature and pressure
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18
Q

Define organelles

A

sub-cellular bodies found in the cytoplasm of cells

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19
Q

Define eukaryotes

A

a group of organisms with cells that have genetic material contained in a membrane-bound nucleus and also contain a number of membrane-bound organelles such as mitochondria and choloroplasts

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20
Q

What are prokaryotes?

A

a group of organisms including bacteria that have few organelles and have no nucleus

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21
Q

What is the cell surface membrane?

A

the membrane that forms the outer boundary of the cytoplasm of a cell and controls the movement of substances into and out of the cell

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22
Q

What are vesicles?

A

membrane ‘bags’ that hold secretions made in cells

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23
Q

What are polar lipids?

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A

lipids with one end attached to a polar group e.g. phosphate group that makes one end hydrophobic and one hydrophilic

24
Q

What are gated channels?

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A

protein channels through the lipid bilayer of a membrane that are opened or closed, depending on cell conditions

25
What is the fluid mosaic model?
the current model of the structure of the cell membrane including floating proteins forming pores, channels and carrier systems in a lipid bilayer
26
What is the cytoplasm?
a jelly-like liquid that makes up the bulk of the cell and contains the organelles
27
What is the nucleus?
an organelle containing the nucleic acids, DNA and RNA as well as protein, surrounded by a double nuclear envelope with pores
28
What is the protoplasm?
the cytoplasm and nucleus combined
29
What is the ultrastructure?
the detailed organisation of the cell, only visible using an electron microscope
30
What does intracellular mean?
inside the cell
31
What is chromatin?
granular combination of DNA bonded to histones found in the nucleus when the cell isn't actively dividing
32
What is the nucleolus?
an extra dense area of almost pure DNA and protein found in the nucleus involved in the production of ribosomes and control growth and division
33
What is the mitochondria?
rod-like structures with inner and outer membranes, site of aerobic respiration
34
What are cristae?
the infoldings of the mitochondrial inner membrane which provide a large area for respiration reactions
35
What are eubacteria?
true bacteria, prokaryotic organisms
36
What is the endosymbiotic theory?
suggests that the mitochondria and the chloroplasts originated as independent prokaryotic organisms that began living symbiotically inside other cells as endosymbionts
37
What are centrioles?
bundles of tubules found near the nucleus and involved in cell division by the production of a spindle of microtubules that move the spindles to opposite ends of the cell
38
What is a spindle?
a set of overlapping microtubules running the length of the cell, formed as the centrioles pull apart in mitosis and meiosis
39
What is the cytoskeleton?
a dynamic, 3D web-like structure made up of microfilaments and microtubules that fill the cytoplasm and gives it structure, keeping the organelles in place and enabling cell movements and transport within the cell
40
What are microfilaments?
protein fibres that makes up part of the structure of the cytoskeleton
41
Define a vacuole
a fluid-filled cavity within the cytoplasm of a cell surrounded by a membrane
42
What are contractile vacuoles?
vacuoles that can fill and empty to help control the concentration of the cytoplasm of simple freshwater animals
43
Define 80S ribosomes
main type of ribosomes found in eukaryotic cells, consisting of ribosomal RNA and protein in ratio 1:1. made up of a 40S subunit and 60S subunit, site of protein synthesis
44
Define 70S ribsomes
found in prokaryotes, mitochondria and chloroplasts. consist of ribosomal RNA and protein in the ratio 2:1, site of protein synthesis and transport proteins. made up of 50S and 30S subunits
45
What is the rough endoplasmic reticulum (RER)?
covered in 80S ribosomes and involved in the synthesis and transport of proteins. large surface area, can transport proteins through exocytosis
46
What is the smooth endoplasmic reticulum (SER)?
smooth tubular structure with no ribosomes, involved in the synthesis and transport of lipids and steroids
47
What is exocytosis?
energy-requiring process by which a vesicle fuses with the surface of the membrane so the contents are released to the outside of the cell
48
What is the golgi apparatus?
stacks of membranes that modify proteins made elsewhere in the cell and package them into vesicles for transport, they also produce materials for plant cell walls and insect cuticles
49
What's a lysosome?
an organelle full of digestive enzymes used to break down worn out cells or organelles, or to digest food in simple organisms
50
Define apoptosis
programme cell death- the breakdown of worn out, damaged or deceased cells by the lysosomes
51
What is the tonoplast?
the specialised membrane that surrounds the vacuole in plant cells and controls movement into and out of the cell sap
52
What is cell sap?
aqueous solution that fills the permanent vacuole
53
What's osmosis?
the movement of water molecules from a region of high to lower water concentration, down a concentration gradient through a partially permeable membrane
54
Define a cholroplast
an organelle adapted to carry out photosynthesis, containing chlorophyll (green pigment)
55
What is cholophyll?
the green pigment largely responsible for trapping light energy, making it available for the plant to use in photosynthesis
56
What are amlyoplasts?
plant organelles that store starch

A Level Biology (32 decks)

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