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B1 Flashcards

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1
Q

What is the main characteristic of a eukaryotic cell?

A

It contains genetic information in the nucleus

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2
Q

What is the main feature of a prokaryotic cell?

A

It does not have a nucleus

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3
Q

What sub cellular structures do all eukaryotic cells contain?

A

Cytoplasm, cell membrane, nucleus and mitochondria

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4
Q

What is the purpose of the vacuole in a plant cell?

A

It helps to keep the plant rigid.
It supports the cell and keeps it upright
It is full of cell sap

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5
Q

What is the purpose of a cell wall?

A

It surrounds the cell and is made of cellulose. It supports the cell

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6
Q

What is the purpose of chloroplasts?

A

Chloroplasts contain chlorophyll.
Chlorophyll transfers energy from the sun to the plant as light, which is used in photosynthesis.
Chloroplasts are the only green part of the plant

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7
Q

What is the role of the nucleus?

A

It controls the cells activities and contains the organisms genetic information (this determines the cells appearance and function)
Contains instructions on how to make new cells or organisms

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8
Q

What is the role of the cell membrane?

A

It is a selective barrier that controls which substances pass in and out of the cell the cell membrane also contains receptor molecules

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9
Q

What is the role of the cytoplasm?

A

It is a ‘jellylike’ substance where the chemical reactions take place

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10
Q

What is the role of the mitochondria?

A

It is where respiration happens. Enzymes, code and oxygen to react together. The reactions transfer vital energy to the organisms

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11
Q

Where is the genetic material min a prokaryotic cell?

A

Floating freely in the cytoplasm. It is one long strand of DNA called the arterial chromosome. It is normally rather circular ( it an exact circle)

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12
Q

What is the role of the slime capsule?

A

It is a later outside the cell wall. It protects the bacterium form drying out and from poisonous substances. It also helps bacteria to stick to smooth surfaces

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13
Q

What is the role of the pili?

A

The pili is tiny hair like structures that enable the cell to attach to structures like the cells that line your digestive tract. Pili are also used to transfer genetic material between bacteria

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14
Q

What is the role of the plasmid?

A

It is a circular piece of DNA that is used to store extra genes. The genes are not normally the bacterium’s day to day survival, but may help the cell in times of stress. For example, this is where antibiotic resistant genes are normally found

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15
Q

What is the role of the flagella?

A

They are ‘tail-like’ structures that allow the cell to move through liquids

(Similar to a sperms tail)

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16
Q

How does staining a cell with iodine help to highlight the cells subcellular structures?

A

It can make it easier to see plant nuclei

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17
Q

How does staining a cell with methylene blue help to highlight the cells subcellular structures?

A

It makes it easier to see the nucleus of an animal cell

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18
Q

How does staining a cell with crystal violethelp to highlight the cells subcellular structures?

A

It stains bacteria cell walls and makes them more visible

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19
Q

What is the equation for magnification?

A

Total magnification =

eyepiece lens magnification x objective lens magnification

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20
Q

What are the advantages/disadvantages/features of a light microscope?

A

It is cheap to buy
It is small and portable
Samples for light microscopes are simple to prepare
Natural colour of sample can be seen (unless staining is used)
Specimens can be both living and dead
Resolution of up to 2x10^-7

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21
Q

What are the advantages/disadvantages/features of an electron microscope?

A

Expensive to buy and operate
Large and difficult to move
Sample preparation is complex
Black and white images produced (however false colour can be added to the image)
Specimens are dead resolution up t 1x10^-10

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22
Q

What is a Transmission electron microscope?

A

A TEM is a microscope that can produce highly magnified images of cells

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23
Q

What is a Scanning electron microscope?

A

An SEM is a microscope that can produce a three dimensional image of a surface

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24
Q

What is the structure of DNA (what are the nucleotides that make up DNA)?

Study These Flashcards
A

Phosphate — deoxyribose — base

25
What are the complentary base pairs for A T C G U?
``` A-T T-A C-G G-C U-A ```
26
What type of helix structure is DNA?
Double helix structure
27
How is a copy of DNA made?
1. A copy of DNA is made called mRNA. This process is called transcription. The DNA unzips and one strand acts like a template. Then complementary base pairs join to the template. There is no thymine (T) so uracil (U) binds with adenine (A) 2. The mRNA detaches itself from the DNA and the mRAN travels through the cell membrane to the ribosomes. This is where the protein is made. 3. Then translation happens
28
What is translation?
1. The mRNA attaches itself to a ribosome 2. Then the proteins are made. The ribosome reads the nucleotides in groups of three (triplets). Each triplet is called a codon 3. Each codon codes for its own amino acid 4. The ribosom continues to read the codons and adds amino acids 5. The amino acids joins to form a chain. This chain is a protein
29
What are enzymes?
Enzymes are proteins that are catalysts in a reaction. They speed up a reaction without being used up themselves
30
Why don’t all enzymes bind to all molecules
Enzymes have specific shaped active sites and can only bind to the type of substrate that fits EXACTLY into the active site. The substrate has to be the exact shape to fit into the enzyme and for the enzyme to denature it, in a similar way that a key has to fit exactly into a lock for the door to open. This is known as the lock and key hypothesis
31
What are the factors that affect enzyme activity?
Temperature, pH, enzyme concentration, substrate concentration
32
How does temperature affect enzyme activity?
Each enzyme has its own optimum temperature. At high temperatures, enzyme and substrate molecules move faster and collide more often. If the temperature becomes too high the amino acid chains in the protein start to unravel, changing the shape of the active site. Then the substrate can no longer bind it the enzyme because it no linger ‘fits’ (lock an key hypothesis). This means that the enzyme has denatured. Once all the enzyme molecules have denatured the reaction stops
33
How does the pH affect enzyme activity?
Each enzyme has its own optimum pH. If the pH is higher or lower than the optimum pH, then the enzyme may unfold and the active site may change shape
34
How does the enzyme concentration affect enzyme activity?
The higher the concentration of enzymes, the faster the rate of reaction. This would be shown as a steepening curve on a graph. Then the graph would start to level off and then the would be a straight verticals line because eventually all the substrate will have been broken down made into larger molecules
35
How does the substrate concentration affect enzyme activity?
The higher the substrate concentration, the higher the rate of reaction, however after a while the graph will level off because the point of saturation would have been reaches (all the enzymes would be blinded to a substrate so adding more substrate wouldn’t make a difference and the substrate would just be waiting for the enzyme to finish its reaction and move onto it.)
36
Which base does A represent?
Adenine
37
Which base does T represent?
Thymine
38
Which base does C represent?
Cytosine
39
Which base does G represent?
Guanine
40
Which base does U represent?
Uracil
41
What are carbohydrates?
Carbohydrates are polymers that are made from molecules such as sugars
42
What is the metabolic rate?
The rate at which your chemical reactions that release energy from food occur
43
What are proteins?
Proteins are polymers. They are formed from amino acids
44
What are lipids
Lipids are the fats and oils that you eat
45
What happens once food is fully digested into soluble glucose, amino acids, fatty acids and glycerol?
The soluble glucose, amino acids, fatty acids and glycerol is then absorbed into your blood stream
46
What is respiration?
Getting energy from food
47
What is the word and chemical equation for aerobic respiration?
glucose + oxygen —> carbon dioxide + water (+energy) | C6H6O6 + 6O2 —> 6CO2 + 6H2O (+ATP)
48
What is the energy produced in respiration used for?
The ATP energy produced during respiration is used: - to stay war, - to move - to make new cells
49
Where does respiration occur in a cell?
In the mitochondria
50
Is respiration exothermic or endothermic?
Exothermic reaction
51
What is equation for anaerobic respiration?
glucose —> lactic acid
52
Why would you want to respire anaerobically?
Anaerobic respiration usually produces energy faster. However lactic acid is produces which is poisonous. The only thing that can break down lactic acid is oxygen so then you start breathing heavily to supply your body with enough oxygen to break down the lactic acid. This is known as oxygen debt.
53
What is the word and symbol equation for fermentation?
glucose —> ethanol + carbon dioxide | C6H12O6 —> 2C2H5OH + 2CO2
54
What happens to the glucose produced in photosynthesis?
- it is used in plant respiration - it is stored in fruit as sucrose - it is turned into starch which acts as the plants food store - it is turned into cellulose which is used in the cell walls - when added with nitrogen it forms proteins which are used for growth and repair - it is turned into fats and oils which are used for growth and as a food store
55
Is photosynthesis an exothermic or endothermic reaction?
Endothermic
56
What is the word and chemical equation for photosynthesis?
carbon dioxide + water —> glucose + oxygen | 6CO2 + 6H2O (+ATP) —> C6H6O6 + 6O2
57
How can you test for starch in a plant?
1. Take a leaf using forceps and place it on a beaker of boiling water to kill the leaf 2. Then place the leaf in boiling ethanol to remove all the chlorophyll 3. Then wash the leaf to remove ethanol off the leaf and to soften the leaf and spread the leaf on a white tile 4. Add a few drops of Iodine and if there is starch present then the Iodine will turn form yellow-Brown blue-black
58
What is the equation for the rate of photosynthesis?
Rate = 1/t
59
What is the inverse square law equation for light intensity?
Relative light intensity = 1/distance from light source squared

Biology (7 decks)

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