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Biology paper 1 > Topic 2 cells > Flashcards

Topic 2 cells Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Give the 5 key structure points of the nucleus

A
  1. Nucleus envelope - double membrane
  2. Nuclear pores
  3. Nucleoplasm - jelly like material
  4. Chromosomes - protein bound linear DNA
  5. Nucleolus - smaller sphere inside site of rRNA production and makes ribosomes
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2
Q

What is the function of the nucleus
(2)

A

Sure of DNA replication and transcription

Contained the genetic code for each cell

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3
Q

Give the structure of the endoplasmic reticulum

A

Rough and smooth endoplasmic reticulum both have folded membranes called CISTERNAE

Rough ER have ribosomes on the cisternae

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4
Q

Give the function of the Endoplasmic reticulum

A

Rough endoplasmic reticulum- protein synthesis

Smooth endoplasmic reticulum- synthesis and store lipids and carbohydrates

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5
Q

Give the structure of the Golgi apparatus

A

Folded membranes making cisternae

Secretary vesicles which pinch off from cisternae

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6
Q

Give the function of the Golgi apparatus
(7)

A
  1. Adds carbohydrates to proteins forming glycoproteins
  2. Produced secretory enzymes
  3. Secrete carbohydrates
  4. Transports, modifies and stores lipids
  5. Forms lysosomes
  6. Molecules are ‘labelled with destination
  7. Finished products are transported to cell surface in golgi vesicles where they fuse with membrane and release the contents
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7
Q

What is the structure of lysosomes?

A

Bags of digestive enzymes - contain 50 different enzymes

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8
Q

Give the function lysosomes
(4)

A
  1. Hydrolyse phagocytic cells
  2. Completely break down dead cells
    (Autolysis)
  3. Exocytosis - release enzymes outside cell to destroy material
  4. Digest work out organelles are reuse the materials
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9
Q

Give the structure of mitochondria
(4)

A
  1. Double membrane
  2. Inner members be called Cristae
    3.fluid centre (mitochondrial matrix)
  3. Loop of mitochondrial DNA
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10
Q

Give the function of mitochondria
(3)

A
  1. Site of AEROBIC respiration
  2. Site OF ATP production
  3. DNA to code for enzymes needed in respiration
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11
Q

Give the structure of ribosomes

A

Small
Made up of 2 sub units of protein and rRNA
80s which are larger found in eukaryotic cells

70s smaller found in prokaryotic cells as well as mitochondria and chloroplasts

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12
Q

What is the function of ribosomes

A

Site of protein synthesis

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13
Q

What is the structure of the vacuole

A

Filled with fluid surrounded by single membrane called tonoplast

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14
Q

What is the function of the vacuole
(3)

A
  1. Makes cell turgid providing support
  2. Temporary store of sugars and amino acids
  3. Pigment colours petals to attract pollinators
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15
Q

What is the structure of chloroplasts

A

Surrounded by a double membrane
Contains thylakoids
Fluid filled storms contains enzymes for photosynthesis

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16
Q

What is the function of chloroplasts

A

Site of photosynthesis

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17
Q

What is the structure of a cell wall

A

Plants - made up of microfibrils amid cellulose

Fungi - made of chitin

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18
Q

What is the function of cell walls

A

To provide structure an strength to the cell

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19
Q

What is the structure of the plasma membrane

A

Found in all cells

Contains phospholipid bilayer - molecules embedded within and attached on outside such as proteins, carbohydrates and cholesterol

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20
Q

What is the function of cell membrane

A

Controls the entrance and exit the molecule

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21
Q

What are the key differences in prokaryotic cells compared to eukaryotic
(5)

A

Much smaller
No membrane bound organelles
Smaller ribosomes
No nucleus
Cell wall made of murein

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22
Q

What 3 additional features Can a prokaryotic cell contain

A
  1. Plasmids
  2. A capsule
  3. Flagella
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23
Q

What is the structure of a virus?

A

Genetic material a capsid an envelope surrounding this and then attachment proteins

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24
Q

How do viruses replicate

A

Replicate inside of host cells

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25
Q

What are the 3 types of microscopes

A

Optical (light)
Transmission electron
Scanning electron

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26
Q

Define magnification

A

The magnification of a microscope refers to how many times larger the image is compared to the object

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27
Q

Define resolution

A

Minimum distance between the two objects on which they can still be viewed as separate, the resolution on an optical microscope is determined by the wavelength of light and the wavelength of beams of electrons in the electron microscopes

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28
Q

Give 5 properties of the optical microscope

A
  1. Bean of light condensed to create an image
  2. Poor resolution due to light having lower wavelength
  3. Lower magnification
  4. Colour images
  5. Can view living samples
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29
Q

Give 5 properties of electron microscopes

A
  1. Beam of electrons condensed to create image
  2. Higher resolution as electrons have shorter wavelength
  3. Higher magnification
  4. Black and white images
  5. Sample must not be living as it need to be in a vacuum
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30
Q

Why must specimens be kept in a vacuum for the electron microscope

A

As electrons are absorbed by air

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31
Q

Explain the difference between the scanning electron (SEM) and transmission electron microscope (TEM)

A

SEM creates 3D images as the electrons don’t go through the specimen they scatter in different ways producing a black and white 3D image

TEM has to have a think sample as electrons had to pass though specimen where some parts absorb electrons more and so are darker

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32
Q

What is the equation for magnification?

A

IAM

Magnification = Image size
Actual size

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33
Q

How do you convert from metres to millimetres

A

X1000

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34
Q

How do you convert from mm to micrometers

A

X1000

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35
Q

How do you convert from micrometers to manometers

A

x1000

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36
Q

What is the first step of cell fractionation

A

Homogenisation

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37
Q

What happens in homogenisation
(4)

A
  1. Cells are broken open to release contents and organelles then separated
  2. The cells must be prepared in a cold isotonic buffered solution
  3. Cell is then homogenised (broken up) using a blender
  4. The solution is then filtered to remove large cell debris
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38
Q

Why must cells be prepared in a cold solution for homogenisation?

A

To reduce enzyme activity

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39
Q

Why must cells be prepared in a isotonic solution for homogenisation?

A

Must be the same water potential to prevent osmosis as this could cause the organelles to shrivel or burst

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40
Q

Why must cells be prepared in a Buffered solution for homogenisation?

A

The solution had a PH buffer to prevent damage to organelles

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41
Q

Give the 2 steps of ultracentrifugation

A
  1. The filtered solution is spin at different speeds in the centrifuge
  2. Organelles separate according to densities
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42
Q

What is differential centrifugation
(3)

A

Centrifuge spine and creates a pellet of most dense organelles as bottom

Centrifuge is first spun at allow speed and increasingly gets faster after the removal of each pellet

Each time supernatant (liquid) removed leaving behind pellet or organelles

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43
Q

Give the order of organelles from most to least dense
(6)

A

Most dense
1. Nuclei
2. Chloroplasts
3. Mitochondria
4.lysosomes
5.endoplasmic reticulum
6.ribosomes

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44
Q

How do eukaryotic cells divide?

A

Mitosis or meiosis

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45
Q

How do prokaryotic cells replicate

A

Binary fission

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46
Q

What are the 3 Key stages in the cell cycle

A

Interphase

Nuclear division

Cytokinesis

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47
Q

What is interphase

A

The longest stage in the cell cycle
When the organelle doubles the cell grows and DNA replicates

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48
Q

What is nuclear division?

A

Can either be mitosis or meiosis creating 2 identical diploid cells or meiosis creating 4 t different haploid cells

Mitosis creates cells with identical DNA for growth and repair

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49
Q

What is cytokinesis

A

Final stage, division of cytoplasm to create new cells

50
Q

What are the 4 stages of mitosis

A

Prophase
Metaphase
Anaphase
Telophase

51
Q

What is a haploid cell?

A

The presence of a single set of chromosomes in an organisms cell

52
Q

What is a diploid cell?

A

2 complete sets of chromosomes

53
Q

Give the 4 key facts about mitosis

A
  1. One round of division
  2. Genetically identical cells are made
  3. Diploid cells are made
  4. Used for growth and repair
54
Q

Explain the process of prophase

A

Chromosomes condenser and become visible
Nucleus disappears

Chromatin condense into chromosomes

Centrioles separate and move to opposite poles of the cell

These centrioles are responsible for creating spindle fibres

55
Q

Explain the process of metaphase

A

Chromosomes align along the equator

The spindle fibres released form poles attach to centromere and chromatid

56
Q

Explain process of anaphase

A

The spindle fibres retract pull away from centromere and chromatids they are bound to words opposite poles causing centromere to divide into 2 and individual chromatids pulled to each side

This stage requires energy in the form of ATP

57
Q

Explain process of telophase

A

Chromosomes are now at each pole and elongate and thin out

Spindle fibres disintegrate
Nucleus reforms

Cytoplasm splits in 2 creating 2 genetically identical Cells

58
Q

What is the mitosis index and how can it be calculated

A

Count how many visible cells are in a particular stage of mitosis

59
Q

What is the equation for mitotic index

A

Number of cells in mitosis
The total number of cells x100

60
Q

Give the 2 steps of binary fission

A
  1. Replication of the circular DNA and of plasmids
  2. Division of the cytoplasm to produce 2 daughter cells each single copy of circular DNA and variable number of plasmids
61
Q

How do viruses replicate

A

They inject their nucleus acid into host and the host cell then replicated the virus particles

62
Q

What model describes a plasma membrane and why?

A

Fluid mosaic model
As the mixture and movement of phospholipids create a mosaic like structure

63
Q

What does the presence of cholesterol in the membrane do?

A

Cholesterol restricts lateral movement of other molecules

This can be useful as makes the membrane less fluid at high temps and prevents water and dissolved ions leaking out

64
Q

What is the purpose of a peripheral protein?

A

Provides mechanical support or connected to proteins or lipids to make glycoproteins and glycolipids act as receptors

65
Q

What is the purpose of integral proteins

A

Protein carriers or channel proteins

66
Q

What is the difference between Carrier proteins and channel proteins

A

Channel proteins from tubes that fill with water allowing water soluble ions to diffuse

Carrier proteins will bind to other ones and large molecule such as glucose and change shape in order to transport them across the membrane

67
Q

What’s meant by membrane partially permeable

A

Only lipid soluble molecules and very small molecules can pass through the membrane

68
Q

What are the 4 key types of transport across membranes

A
  1. Diffusion
  2. Facilitated
  3. Active transport
  4. Osmosis
69
Q

What is simple diffusion?

A

A net movement of molecules from area of high concentration to an area of lower concentration until equilibrium is reached

Does not require ATP

70
Q

What is facilitated diffusion?

A

Proteins used to transport molecules they movement of ions and polar molecules are transported via channel and carrier proteins

71
Q

What is osmosis

A

Movement of water from an area of higher water potential to area of lower water potential across a partially permeable membrane

72
Q

What is meant by isotonic?

A

Water potential is same as the solution and the cell within the solution

73
Q

What is meant by hypOtonic

A

The water potential of a solution is more positive (closer to 0) than the cell

Plump cells full of water

74
Q

What is meant by hypERtonic

A

Water potential of a solution is more negative than the cell

Shrivelled cell as all water has left it

75
Q

What is active transport?

A

The movement of a substance from a low concentration to a high concentration using metabolic energy and a CARRIER protein

76
Q

Give the 5 steps of active transport

A
  1. Transport through carrier protein
  2. Molecule bonds to complementary receptor on Carrier protein
  3. ATP bonds to the carrier protein from inside cell and is hydrolysed
  4. Causes carrier protein to change shape and release molecule on other side
  5. Phosphate ion released and protein returns to its original shape
77
Q

Explain why co transport is needed for glucose and sodium

A

To absorb glucose from the lumen to the gut requires high concentration of glucose in the lumen compared to epithelial cell

But there is more glucose in the epithelial cells

78
Q

Explain co transport of glucose and sodium in 5 steps

A
  1. Sodium ions actively transported out of epithelial valley into the blood
  2. This reduces the sodium ion conc in epithelial cell
  3. Sodium ions can diffuse from Lumen down their conc gradient into epithelial cell
  4. Protein the sodium ions diffuse through is a co-transported protein so glucose or amino acids are also attached and transported into epithelial cell against their concentration gradient
  5. Glucose moves by facilitated diffusion from epithelial cell into blood
79
Q

What are the 2 main adaptions for rapid transport

A

An increase in surface area

An increase in number of carrier and channel proteins

80
Q

What are lymphocytes

A

Cells that can identify the presence of pathogens and foreign harmful substances and deftly them

81
Q

How can lymphocytes distinguish between pathogens and self - cells

A

Each type of cell has specific molecule on its surface that identifies it, these molecules are proteins as true 3D tertiary structure enables lots of unique and identifiable shapes

82
Q

What are the 4 different non-self cells that lymphocytes can recognise

A
  1. pathogens
  2. Cells from tiger organisms
  3. Abnormal body cells such as cancer
  4. Toxins
83
Q

What is an antigen

A

Molecules that generate an immune response by lymphocyte cells when detected in the body

84
Q

What is antigen variability

A

Pathogenic DNA mutates so shapes of the antigen will change so any previous immunity will no longer be effective

85
Q

Give 2 examples of physical Barrier

A

Eyelashes and skin

86
Q

Give 2 examples of chemical barrier

A

Stomach acid and tears

87
Q

What are the 2 responses of white blood cells?

A

Phagocytosis - non-specific

Lymphocytes- specific

88
Q

What is a phagocyte?

A

A macrophage (white blood cell)

89
Q

Describe the process of phagocytosis in 6 steps

A
  1. Any chemicals or debris released by pathogens attract phagocytes
  2. Many receptor binding points on surface of phagocytes they will attach chemicals or antigens on the pathogen via these receptors
  3. Phagocyte changes shape to move around and Engulf the pathogen
  4. Once engulfed the pathogen is contained in a phagosome vesicle
  5. A lysosome within phagocyte will fuse with the phagosome and release its contents
  6. Lysozyme enzyme released into phagosome which then hydrolysed the pathogen destroying it and so liable products are then absorbed
90
Q

Where do T cells mature

A

Thymus

91
Q

What response involves T cells

A

Cell mediated

92
Q

What is an antigen presenting cell
Give 4 examples

A

Any cell that presents a non self antigen on their surface

Infected body cells present these viral antigens

A macrophage which has engulfed and destroyed a pathogen will present these

Cells that have been transplanted

93
Q

Describe the cell mediated response in 4 steps

A
  1. Once pathogen engulfed and destroyed by phagocyte antigens are now cell surface antigens
  2. Helper T cells have receptors on their surface and attach to the antigens of APC
  3. Once attached activated the helper T cells to divide by mitosis
  4. Cloned helper T cells differentiate
    Some remain as helper T cells and active B lymphocytes
    Others stimulate macrophages to perform phagocytosis
94
Q

How do cytotoxic T cells destroy cells

A

They release a protein called perforin which embeds into cell surface membrane makes a pore so substances can enter or leave the cell

95
Q

What are B lymphocytes

A

White blood cells that mature in the bone marrow

96
Q

What is the response involved with B lymphocytes

A

Humoral

97
Q

How are B cells activated

A

There’s 10 million different B cells in your body which are complementary to 10 million different antigens

Antigens in the blood collide with their complementary antibody on a B cell B cell then takes in the antigen by endocytosis and presents it on its cell surface membrane

When B cells collide with helper T cells activated B cells to go through clonal expansion and differentiation

98
Q

What can B cells differentiate into

A

Plasma cells or memory B cells

99
Q

What is the role of plasma cells

A

To make antibodies

100
Q

What is the role of memory B cells

A

Divide rapidly into plasma cells when re infected with the same pathogen

Can live decades

Don’t make antibodies
This is a form of active immunity

101
Q

Explain the graph you would see for primary and secondary immune response

A

So when your initially exposed to a new pathogen the number of antibodies your body makes would be small as it’s a new foreign pathogen and then you would eventually make more and overcome the illness but he number of this specific antibody wouldn’t go to 0 it would just lower so that when you are reinfected with a secondary exposure your body creates lots of specific antibodies to fight the illness before you get ill

102
Q

What is an antibody

A

A protein produced in response to counteracting a specific antigen

103
Q

What is agglutination

A

Antibodies are flexible and so can bind to multiple antibodies and so can clump together

104
Q

What is passive immunity

A

When antibodies are introduced to body

105
Q

Give an example if passive immunity

A

Breast milk

106
Q

What is active immunity

A

Immunity created by your own immune system following exposure to pathogen

107
Q

What is natural active immunity

A

Following infection and creation of antibodies and memory cells

108
Q

What is artificial active immunity

A

Vaccine

109
Q

What is a vaccine

A

A small amount of weakened antigen introduced usually by injection

110
Q

What is herd immunity

A

If enough of population is vaccinated pathogen cannot spread easily amongst the population

111
Q

What is the core of HIV

A

Genetic material (RNA) and the enzyme reverse transcriptase which is needed for viral replication

112
Q

What is the capsid of HIV

A

Outer protein coat

113
Q

What is the envelope for HIV

A

Extra outer layer made from membrane of host cell

114
Q

What are the protein attachments on HIV

A

Exterior of envelope allows virus to attach to host helper T cells

115
Q

How does HIV replicate in helper T cells
(4)

A

1.HIV transported around in blood until attached to a CD4 protein on helper T cell

  1. HIV protein capsule fuses with helper T cell membrane enabling RNA and enzymes from HIV to enter
  2. HIV enzyme reverse transcriptase copies thee viral RNA into DNA copy and moves to helper T cell nucleus
  3. mRNA is transcribed and helper T cell starts to create viral proteins and make new viral particles
116
Q

What is AIDS

A

when a replicating virus in the helper T cells interfere with normal functioning immune system left vulnerable to cancer and infections

117
Q

What are monoclonal antibodies

A

Single type of antibody that can be isolated and cloned

118
Q

How can cancer be treated by monoclonal antibodies

A

Some monoclonal antibodies complementary to the shape of the antigens on outside of cancer cells so they will attach preventing chemicals binding to inhibit uncontrollable cell division

119
Q

What does the ELISA test stand for

A

Enzyme linked immunosorbent assay

120
Q

How does the pregnancy test work

A
  1. First mobile antibody, complementary to the antigen being tested for and has coloured dye attached
  2. A second antibody complementary in shape to the antigen immobilised in the test
  3. A third antibody is immobilised and complementary in shape to the first antibody
121
Q

How does ELISA test work
(7)

A
  1. Add sample at bsd if beaker
  2. Wash to remove unbound test sample
  3. Add antibody complementary in shape to the antigen you are testing the presence of
  4. Wash to remove unbound antibody
  5. Add 2nd antibody that is complementary to the first antibody and binds to the first.
    The 2bd antibody has an enzyme attached to it rinse any unbound antibodies
  6. Substrate for enzyme is added (colourless) this substrate produces coloured products with the enzyme
  7. Presence of colour indicates presence of antigen
122
Q

What are the ethical issues of monoclonal antibodies

A

Animal testing

Biology paper 1 (4 decks)

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