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A Level Biology Y1 > Cells and Cell Transport > Flashcards

Cells and Cell Transport Flashcards

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1
Q

what are prokaryotes

A

very small single celled organisms with no nucleus and no membrane bound organelles in their cytoplasm.

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2
Q

prokaryotes will always have? (5)

A
  • a cell wall
  • a cell surface membrane
  • a circular DNA that’s free in the cytoplasm
  • ribosomes
  • cytoplasm
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3
Q

prokaryotes might have? (3)

A
  • a capsule surrounding the cell wall
  • one or more plasmids
  • one or more flagella
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4
Q

what are eukaryotes

A

Single or multicellular organisms containing a nucleus a cytoplasm and other organelles

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5
Q

differences between prokaryotes and eukaryotes

A
  • prokaryotes have smaller 70s ribosomes , eukaryotes have bigger 80s ribosomes
  • prokaryotes have no nucleus, eukaryotes do
  • DNA is circular in prokaryotes, DNA is linear in eukaryotes
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6
Q

similarities between prokaryotes and eukaryotes

A
  • both have ribosomes
  • both have a cell membrane
  • both are alive
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7
Q

what is binary fission

A

A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size

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8
Q

function and structure of a nucleus

A

Contains the genetic material determining the development structure and function of the cell

-bound by a double membrane, a nuclear envelope which has nuclear pores

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9
Q

function and structure of ribosomes

A

-made of protein and ribosomal RNA

  • site of protein synthesis
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10
Q

structure of the endoplasmic reticulum

A

flattened membrane sacs which form an internal transport system in the cell

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11
Q

smooth Endoplasmic reticulum function

A

-involved in the production and transport of lipids

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12
Q

what are lysosomes

A

simple sacs containing hydrolytic enzymes surrounded by a single membrane formed by the Golgi apparatus

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13
Q

lysosome’s function? (4)

A
  • fuse with the vesicles during phagocytosis releasing hydrolytic enzymes which digest the material inside
  • engulfs and digests non functioning organelles
  • release of enzymes outside cell
  • autolysis
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14
Q

Rough Endoplasmic Reticulum function

A
  • has ribosomes that produce secretory proteins which are sent to the Golgi apparatus for packaging and/or modification
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15
Q

3 functions of the Golgi Apparatus

A
  • adds carbohydrates to proteins received from RER to form glycoproteins
  • packages proteins/glycoproteins into Golgi vesicles for secretion
  • Produces lysosomes
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16
Q

function of mitochondria

A
  • involved in aerobic respiration which produces ATP
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17
Q

Mitochondria structure

A
  • bound by two membranes forming an envelope around an inner matrix
  • the folds of the inner membrane = cristae

-matrix contains enzymes for respiration, also contains DNA and ribosomes

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18
Q

function of chloroplast

A

Site of photosynthesis

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19
Q

Chloroplast structure (4)

A
  • flattened biconvex discs surrounded by an envelope consisting of two membranes
  • flattened sacs called thylakoids form stacks called grana
  • grana provides a large SA for the chlorophyll molecules
  • membrane system is surrounded by the stroma which contains enzymes sugars and starch granules
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20
Q

function of cell wall

A

Provides support, strength and shape to the cell

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21
Q

Cell Wall Structure

A

-consists of cellulose microfibrils embedded in a matrix containing other polysaccharides

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22
Q

Algae Cell Wall consists of? (3)

A
  • cellulose
  • glycoproteins
  • a mixture of both
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23
Q

Fungi Cell Wall contains? (3)

A
  • chitin (nitrogen containing polysaccharide)
  • glucan
  • glycoproteins
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24
Q

vacuole contains? (3)

A
  • soluble sugars
  • salts
  • sometimes pigment
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25
Q

What is cell differentiation?

A

The process in which cells become specialized.

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26
Q

What are tissues?

A

-groups of similar cells which perform a specific function

27
Q

What is an organ?

A

A group of different tissues that work together to perform a certain function.

28
Q

What is an organ system?

A

A group of organs working together to perform a particular function

29
Q

What is an organ system?

A

A group of organs working together to perform a particular function

30
Q

What is an epithelial cell?

A

cells in the small intestine specialised for the absorption of digested food products

31
Q

Epithelial cell adaptations? (2)

A
  • folded cell surface membrane into microvilli to increase surface area
  • numerous mitochondria to provide ATP for the release of energy. (active transport)
32
Q

What is ultracentrifugation?

A
  • centrifugation is a method used to separate structures of different density
33
Q

Optimal conditions for UC (3)

A

-Isotonic solution as it prevents osmotic movement in or out of organelles

-Ice cold temperature to minimalize/ stop enzyme activity (preventing autolysis of the organelles)

  • buffer solution to maintain the pH so the proteins aren’t denatured
34
Q

Describe the process of Ultracentrifugation

A

-cells are broken open by homogenising a tissue in optimal conditions using a blender

-resulting suspension may be filtered to remove cell debris eg. cell walls or unburst cells

-the homogenate is centrifuged at a low speed which makes the densest organelles form a pellet at the bottom

  • the supernatant (the liquid) is centrifuged again at a higher speed for longer where the 2nd densest organelles forms a pellet

-repeat process by increasing speed and duration of centrifugation of in order to get several other pellets

35
Q

Order of pellet formation

A

-nuclei

-chloroplast( if plant cell)

-mitochondria

-endoplasmic reticulum

-ribosomes

36
Q

In a light microscope the specimen must be?

A

-thin so that light passes through it and it is visible

-be stained in order to make structures visible

37
Q

How does an electron microscope work?

A

It uses a beam of electrons which are focused using electromagnets.

38
Q

Differences between Scanning Electron Microscope and Transmission Electron Microscope

A
  • TEM has a higher resolution than SEM
  • TEM produces images of internal structures, SEM produces images of external structures
  • TEM gives 2d image, SEM gives 3d image
39
Q

Similarities between Scanning Electron Microscope and Transmission Electron Microscope

A
  • Both use electron beams focused by electromagnets
40
Q

Advantage of electron microscope

A

-uses electrons which have a shorter wavelength and therefore greater resolution than light microscopes

-unlike electron microscopes, light microscopes get blurred at higher magnification

41
Q

I AM equation?

A

Image size = Actual Size x Magnification

42
Q

Why is the cell-surface membrane described as a fluid-mosaic?

A

-the phospholipid molecules in the bilayer are constantly moving about giving a fluid structure

  • the protein molecules are unevenly distributed throughout the membrane forming a mosaic
43
Q

How are phospholipids arranged in a membrane?

A
  • hydrophilic heads of phospholipids oriented either inwards towards the cytoplasm or outwards towards the watery extra-cellular fluid
  • hydrophobic tails are oriented towards each other away from water.
44
Q

What passes through a membrane during simple diffusion?

A

-very small molecules e.g, carbon dioxide and oxygen

45
Q

What does a phospholipid bilayer prevent from going through?

A
  • water soluble ions and polar molecules
46
Q

Cholesterol in the cell membrane does what?

A
  • provides strength and regulates fluidity of fatty acid chain
47
Q

Channel Proteins in the cell membrane does what?

A
  • Helps molecules be transported through the membrane by Facilitated Diffusion
48
Q

Carrier Proteins in the cell membrane does what?

A
  • Helps molecules be transported through the membrane by facilitated Diffusion and active Transport
49
Q

Glycoproteins and Glycolipids Function

A

involved in cell to cell recognition and able to act as receptors

50
Q

Intrinsic and Extrinsic Protein

A

intrinsic - spans the whole membrane

extrinsic - doesn’t span the whole membrane

51
Q

What is diffusion?

A
  • the net movement of molecules from a high concentration to a low concentration until the molecules are equally distributed
52
Q

Rate of Diffusion equation (Fick’s Law)

A

Surface Area x Concentration Difference/Diffusion Distance

53
Q

What factors increase Rate of Diffusion?

A

Increased Surface Area

Increased Concentration Difference

Decreased Diffusion Distance

54
Q

What is facilitated diffusion

A
  • Diffusion aided by Carrier and Channel Proteins without the use of energy
55
Q

What is Active Transport?

A
  • the movement of ions or molecules across a cell membrane against the conc gradient through carrier proteins and requiring energy.
56
Q

How do carrier proteins work?

A
  • the carrier protein has a complementary shape to the polar molecule being transported
  • they bind which causes the carrier protein to change shape and transport molecules across the membrane
57
Q

Factors that decrease Active Transport

A
  • Lowering of temperature
  • Lack of Oxygen
  • Metabolic and Respiratory Inhibitors
58
Q

What is Osmosis?

A

Diffusion of water through a selectively permeable membrane

59
Q

What is Water Potential?

A

The potential tendency of water molecules to leave a solution by osmosis

60
Q

Cell turgor during osmosis?

A
  • as water enters the cell, the vacuole enlarges and the vacuole, cytoplasm and cell membrane exert an outward turgor pressure on the cell wall
61
Q

What happens to red blood cells in a hypertonic solution?

A
  • the cell has a higher water potential than the solution so water moves out of the cell and into the solution which makes the cell shrivel and become flaccid.
62
Q

What happens to red blood cells in a isotonic solution?

A
  • the solution has the same water potential as the cell so there is no net movement of water.
63
Q

What happens to red blood cells in a hypotonic solution?

A
  • the cell has a lower water potential than the solution and so water moves into the cell which causes swelling and eventually bursting of the cell

A Level Biology Y1 (8 decks)

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