Biology Alevel > Unit 2 > Flashcards

Unit 2 Flashcards

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1
Q

What are the components of an animal cell

A

. Nucleus
. Mitochondria
. Vacoule
. Cytoplasm
. Golgi aparatus
. Vesicles
. Lysosomes
. Centriols
. Plasma membrane (cell membrane)
. Rough Endoplasmic reticulum
. Smooth Endoplasmic reticulum
. Ribsomes
. Micro tubules

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2
Q

Describe the function of the squamous epithelial cell

A

. Helps protect from tissues
. Helps with diffusion
. It is in the alvioli. It helps oxygen diffuse through as it has thin layers

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3
Q

Describe the function of an epithelium cell with microvilli

A

In the small intestine, adds more surface area so faster diffusion and active transport

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4
Q

What are the components of a plant cell

A

. Cell membrane
. Smooth Endoplasmic reticulum
. Ribsomes
. Chloroplast
. Nucleus
. Rough Endoplasmic reticulum
. Golgi aparatus
. golgi vesicle
. Mitochondria
. Vacoule
. Cytoplasm
. Nuclear envelope
. Cell wall

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5
Q

Describe the functions of the route hair cell

A

. Has a large surface area for active transport and diffusion.
. It takes in nutrients, minerals and water from the soil that the plants need.
. They have lots of Mitochondria as it needs energy for active transport

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6
Q

Describe the function of the paliside cell

A

Helps with photosynthesis as it has many chloroplasts

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7
Q

What is the function of the plasma membrane

A

Regulates movement of substances in and out of the cell. It also has receptors which allows it to respond to chemicals like hormones

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8
Q

What is the function of the nucleus

A

Controls the cells activités (by controlling transcription of DNA). The DNA contains instructions to make proteins. The nucleus has pores to help substances like RNA move between the nucleus and cytoplasm. The nucleus also makes ribsomes

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9
Q

What is the function of the mitochondria

A

. Sight of aerobic respiration where atp is produced and energy is released. They are found in large numbers in cells that are very active and require energy

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10
Q

What is the function of the chloroplast

A

This is the sight where photosynthesis takes place. Some parts of photosynthesis happen in the thylaloid and other parts happen in the stroma (a thick fluid found in the chloroplasts)

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11
Q

What is the function of the golgi aparatus

A

It packages and processes new lipids and proteins. It also makes lysosomes

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12
Q

What is the function of the golgi vesicle

A

Stores lipids and proteins made by the golgi aparatus
. transports them out of the cell via the cell surface membrane

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13
Q

What is the function of the lysosomes

A

Contains digestive enzymes called lysozymes. These are used to digest invading cells or break down worn out components of the cell

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14
Q

What is the function of the ribsomes

A

Where protien synthesis occurs

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15
Q

What is the function of the rough Endoplasmic reticulum

A

Folds and processes proteins that has been made at the ribsomes

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16
Q

What is the Fuction of the smooth Endoplasmic reticulum

A

Synthesises and processes lipids

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17
Q

What is the function of the cell wall

A

Supports the cell and prevents them from changing shape

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18
Q

What is th function of the vacoule

A

Helps to maintain pressure inside the cell. It stores waste products and other substances. Changes in volume effect turgidity of the cell

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19
Q

What is the function of the centriols

A

Form a spindle shaped structure of protien fibres on which the chromosomes move during nuclear divison

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20
Q

What is the structure of the nucleus

A

. Large organelle
. enclosed by a double membrane (an envelope)
. perforated by pores.
. Contains chromosomes and one or more nuclei

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21
Q

What is the structure of the ribsomes

A

. Very small organelle not bound to a membrane
. Consists of a large and a small subunit
. Made of protein and RNA

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22
Q

What is the structure of the golgi aparatus

A

Stack of membrane bound flattened sacs in the cytoplasm

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23
Q

What is the structure of the mitochondria

A

. Has an outer membrane and an inner one which is folded to form cristea
. The inner membrane is the matrix containing enzymes, a circular DNA molecule and ribsomes

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24
Q

What is the structure of the cell wall

A

Consists of cellulose microfibrils and other polysaccharides

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25
What is the structure of the chloroplast
. Surrounded by 2 membranes . Contains matrix called stroma containing grans which have cholorphyl in them . Stroma contains circular DNA, ribsomes and start grains
26
What is the structure of the centriols
. A pair of cylinders . Each cylinder is made up of 9 fibres
27
What is the structure of the lysosomes
A vesicle containing digestive enzymes
28
What is the structure of the rough Endoplasmic reticulum
. A complex network of flattened, membrane bound sacs called cisterea. . Often has ribsomes on the cytoplasmic side
29
What is the structure of the cell membrane
. A phospholipid bilayer with intrinsic and extrinsic protien molecules
30
What is the structure of the vacoule
. A sac bound by a single membrane . Contains cell sap wich is a solution of mineral salts, pigments, organic acids and other substances
31
What is a tissue
A group of similar cells working together to perform a particular function
32
What is An organ
A group of different tissue working together to perform a particular function
33
What is an organ system
A group of organs working together to perform a particular function in the body
34
What is unicellular
An organism consisting of only 1 cell
35
What is multicellular
An organism consisting of many cells
36
Why may cells contain many mitochondria
. Cells require energy for metabolic reactions and processes such as atp and protein synthesis . Active transport
37
Why may cells contain ribsomes
Cells need protien and need to produce protein
38
What are the similarities and diferences between plant cells and algae cells?
. Plant cells are multicellular, algae cells are unicellular . Plant cells are prokaryotic where as algae cells are ukaryotic olthough they are not always ukaryotic . Not all algae have same chloroplast . Plant cell have nucleus whereas not all algea have nucleus . Have same flagella . Both produce glucose from photosynthesis
39
What are the similarities and diferences between plant cells and fungal cells
. Both have plant cells . Plant cells have cellulose cell wall where as fungal cells have karatine cell wall . Both ukaryotic
40
What are the components of a prokaryotic cell
. Loop of DNA . Plasmids . Flagellum . Slime capsule . Cell wall made of murein . Cell membrane . 70s ribsomes
41
What is the function of the single loop of DNA
Stores genetic info for replication
42
What is the function of the flagellum
For locomotion/movement
43
What is the function of the slime capsule
. Protects from immune cells . Prevents cell from drying
44
What is the function of the cell wall made of murein
Protects against mechanical damage
45
What is the function of the plasmids
. Is rings of DNA. The DNA contains genes for survival eg: antibiotic resistant genes
46
Describe the process of binary fission
. Circular DNA and plasmids is replicated and DNA replicated once. Plasmids can replicate many times . The cell increases in size. The DNA loop moves to oposite poles of the cell . Cytoplasm begins to divide and new cell wall begins to form . Cytoplasm divides and 2 new daughter cells are produced. Each daughter cell has a loop of DNA and multiple plasmids
47
What are the components of a HIV virus particle
. Attachment protein/glycoprotein - helps HIV attach to the host helper Y cells . Viral envelope - extra outer layer made of lipid, made of membrane stolen from the cell membrane of a previous host cell . Reverse transcriptase - enzyme needed for virus prelipcation. Allows RNA to be copied into DNA . Genetic material - RNA . Capsid - outer costing of protien
48
What are the steps of virus replication?
1. Attachment 2. Fusion 3. Reverse transcription 4. Integration 5. Replication 6. Assembly 7. Budding
49
What is the definition of magnification
The ability to make small objects seem larger
50
What is the definition of resolution
The ability to distinguish 2 objects that are closer together
51
What is the equation for magnification
Image size = actual size × magnification
52
What are the diferent components to a light microscope
. Eyepiece . Coarse focus . Handle . Stage . Objective lenses . Specimen slide . Base
53
Describe how light microscope forms images What are pros and cons
. Use light to form an image. + gives image in colour + can view living organisms - lower resolution and magnification than electron
54
Describe how TEM microscope forms images What are the pros and cons
. Uses electromagnets to focus a beam of electrons, which is then tranmitted through the specimen. . Denser parts of the specimen absorb more electrons that make them look darker on the image you end up with + high resolution images, so u can see internal structure of organelles - can only he used on thin specimens - can only view dead organisms - not in colour
55
Describe how SEM microscope forms images What are the pros and cons
. Scan a beam of electrons across a specimen. This nocks electrons off specimens which are gathered in a cathode ray tube to form an image + image can be 3D + can be used on thick specimens - gives lower resolution images compared to TEM - can only view dead organisms
56
What are the 3 steps to cell fractionation
. Homogenisation . Filtration . Ultracentrifugation
57
What happens during homogenisation
. Can be done in diferent ways eg: by vibrating or grinding I'm a blender . This breaks up the plasma membranes releases organelles into the solution . Solution should be ice cold to reduce activity of the enzymes that break down organelles . Solution should be isotonic - meaning it should have the same concentration of chemicals as cells being broken down, to prevent osmosis damaging organelles . Buffet Solution should be added to maintain PH
58
What happens during filtration
. Cell solution should be filtered through a gauze to separate large tissue or dead cells . The much smaller organelles pass through the gauze
59
What happens during ultracentrifugation
. Cell fragments are put into a tube. The tube is out in s centrifuge and is spun at low speed. Heaviest organelles go to the bottom of the tube due to the centrifuge. They create a thick sediment at the bottom of the tube called a pellet. . The rest of the solution is put back into the centrifuge and is spun at a higher speed. This is repeated at higher speeds until the desired product is obtained
60
What are the diferent phases of mitosis
. Interphase . Prophase . Metaphase . Anaphase . Telophase . Cytokenisis
61
What happens during interphase
. Cell grows . Dna replicates . Proteins are synthesised . Organelles are synthesised . Cell does not divide yet .
62
What happens during prophase
. Chromosomes condense and become visible . They become shorter and thicker . Centriols start moving to opposite ends of the cell, forming a network of protein fibres called spindle. . The nuclear envelope then breaks down, and chromosomes lie free in the cytoplasm
63
What happens during metaphase
Chromosomes (each with 2 chromatids) line up in the middle of the cell and become attached to the spindle by the centromere
64
What happens during anaphase
. The centriols divide, separating each pair of chromatid. . The spindles contract . Pulling each chromatid to the opposite end of the cell, centromere first, making the chromatids appear v shaped
65
What happens during telophase
. Chromatids reach the opposite end of the spindle and uncoil, becoming long and thin again . Nuclear envelope forms around each group of chromosomes, so there are now 2 nuclie
66
What happens during cytokenisis
Devision of cell membrane and cytoplasm takes place, leaving 2 genetically identical daughter cells
67
What is cancer
A tumour, made as a result of uncontrollable cell devision, that invades surrounding tissue
68
What is a tumour
A group of cells grouped together. Made due to uncontrollable cell devision
69
What is a mutation
Mutations are changes in the base sequence of an organisms dna
70
What is the mitotic index
It is the proportion of cells undergoing mitosis
71
How do you calculate mitotic index
Mitotic index = number of cells with visible chromosomes ÷ total number of cells observed
72
What are the different components of a cell surface membrane
. Glycolipid . Cholesterol . Extrinsic protein . Phospholipids . Glycoprotien . Intrinsic protein . Unsaturated fatty acid . Amino acids
73
What is the function of phospholipids in the cell surface membrane
. Allows small non polar substances to enter and leave the cell . Prevents large substances from entering and leaving the cell . Gives the membrane fluidity/flexibility
74
What is the function of cholesterol in the cell surface membrane
. Limits movement of other molecules including phospholipids . Makes membrane less fluid at high temperatures . Prevents leakage of water and disolves ions from the cell
75
What is the function of intrinsic proteins in the cell surface membrane
. It is protein on the inside of the cell surface membrane . Is channel protein . Is carrier protein . Acts as hormone receptors . Helps to transport substances
76
What is the function of extrinsic proteins in the cell surface membrane
. These are proteins on the outside of plasma membrane . Functions to give mechanical support to the membrane . Can associate with glycolipids to act as hormone receptors
77
What is the function of glycoprotiens in the cell surface membrane
. It is made up of carbohydrate protein . Maintains stability of membrane . Acts as a cell recognition sight eg: self antigens . Receptors for hormones and neurotransmitters
78
What is the function of glycolipids in the cell surface membrane
. It is made up of lipid and carbohydrate covelently bonded . It maintains the stability of the membrane . Acts as a cell recognition site eg: blood groups . Helps cells attach to eachother to form tissues
79
What is simple diffusion? Give an example
The passive movement of molecules from a high concentration to a low concentration, down a concentration gradient, directly across the phospholipid bilayer Eg: CO² and O² moving directly through the cell membrane of alveoli and capillaries
80
What is facilitated diffusion? Give an example
The passive movement of molecules from a high concentration to a low concentration down a concentration gradient using a channel protein Eg: glucose, amino acid absorption in digestive system
81
What are some features that simple diffusion has
. Only works with small, non polar molecules
82
What are some features of facilitated diffusion
. Uses carrier or channel proteins . Works with polar molecules
83
What are some aspects simple and facilitated diffusion have in common
. Both work down a concentration gradient . ATP is not required
84
Explain how carrier proteins work
. Molecule attaches to carrier protien in the membrane . The protein changes shape . The molecules move from an area of high concentration to an area of low concentration, working down a concentration gradient . The molecules are released to the opposite side of the membrane . This does not require energy
85
What is the definition of water potential
The likelihood of water molecules to diffuse out of or into a solution
86
What is the definition of osmosis
Water molecules move from an area of an area of high concentration to an area of low concentration through a partially permeable membrane
87
What is the definition of a concentration gradient
The path from an area of high concentration to an area of low concentration. Particles diffuse down a concentration gradient
88
What is a eukaryotic cell
Complex cell containing a nucleus enclosed in a nuclear envelope with membrane bound organelles
89
Name 3 examples of eukaryotic organisms
Animal, plant, fungi
90
What does the nucleolus do
Makes ribosomes and ribosomal rna
91
What is the function of cell walls in prokaryotes
Provides structure and protection, made of murine (a glycoprotien)
92
What is the structure of a virus
Genetic material (DNA and RNA) , a capsid and attachment proteins
93
What is the function of attachement protiens
They binds to complementary receptors proteins on the hosts cell surface
94
How do viruses replicate
. Attach to host cell using attachment proteins . Inject genetic material into host cell . The host cells DNA is used to make virus DNA and make new viral components . New viruses are assembled and released, often destroying the host cell
95
Why are viruses not considered living
They can't reproduce or carry out metabolism without a host cell
96
Hat is the difference between prokaryotic and viral genetic material
Prokaryotes have circular DNA, viruses have either DNA or RNA which can either be single or double stranded
97
How can mitosis be observed in a lab?
By preparing a root tip squash and viewing cells under a microscope after staining the chromosomes
98
Why are root tips used to observe mitosis
They are regions of active cell devision (Merristem tissue), so many cells will be in stages of mitosis
99
What stain is commonly used to observe chromosomes in mitosis
Acetic orcein or toluidine blue, which binds to DNA to make chromosomes visible under the microscope
100
How is the mitotic index useful
It indicates the proportion of cells undergoing mitosis, useful for studying growth, cancer or the effect of treatments
101
How is a root tip squash slide prepared
. Cut root tip . Soften it in acid . Stain it . Place it on a slide and squash gently under cover slip
102
Why must the root tip be squshed gently
To spred out the cells so chromosomes in each nucleus can be seen clearly
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