B3 Flashcards

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1
Q

What is DNA

A

DNA is two strands coiled together to form a double helix. Each of the strands contains chemicals called bases and there are for different types. There are cross links between the strands to for pairs of bases..

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2
Q

Each gene has coded…..

A

genetic information

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3
Q

What are chromosomes?

A

They are long, coiled up molecules of DNA - they are divided into sections called genes

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4
Q

What do genes contain? What do they code for?

A

The genetic code consist of different sequences of base pairs in a particular length of DNA. Each gene codes for a particular protein

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5
Q

Where are the proteins made and why is a copy of the gene needed?

A

The Proteins are made in the cytoplasm. A copy of the gene is needed as the gene cannot leave the nucleus; they are in chromosomes

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6
Q

What are the four bases of DNA?

A

A, T, G, C

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7
Q

Describe complementary base pairing

A

A always pairs with T, and G always pairs with C

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8
Q

How does protein structure determine the DNA base code?

A

The base sequence determines the amino acids and each amino acid is coded by a sequence of base triplets

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9
Q

How does the code needed to produce a protein carried?

A

The code is carried from the DNA to the ribosomes by a molecule called mRNA

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10
Q

How does DNA control cell functions?

A

It control the production of proteins, some of these are enzymes.

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11
Q

How did Watson and Crick use data from other scientists to build the model of DNA?

A

W and C used x-ray data showing there were two chains wound in a helix. They also obtained data indicating the bases occurred in pairs.

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12
Q

Why are new discoveries not accepted or rewarded immediately?

A

They need to be repeated and tested by other scientists to test the work; they need verify it

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13
Q

What are proteins made of?

A

They are made from long chains of amino acids

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14
Q

What is collagen?

A

Collagen - structural protein makes up structure of body.

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15
Q

What is an enzyme?

A

They are biological catalysts as they catalyse chemical reactions occurring in living cells e.g respiration, photosynthesis, protein synthesis. They also have high specificity in for the substrate molecule

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16
Q

Describe the lock and key mechanism

A

The substrate molecule fits into the active site. This is called specificity as the substrate has to be the right shape, like a key

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17
Q

What will change the rate of the reaction in an enzyme catalysed reaction?

A

pH and temperature change away from optimum

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18
Q

How is enzyme activity affected by temperature and pH?

A

Low temperatures mean lower collision rates
Extremely high pH and temperature means enzymes denature
Denaturing is irreversible and damages enzymes (active site)

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19
Q

What is temperature coefficient? (Q10)

A

Rate at higher temperature / rate a lower temperature

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20
Q

What is insulin?

A

Hormone made in pancreas. Traces in blood stem to target irfan. It regulates blood sugar level.

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21
Q

What is haemoglobin?

A

In red blood cells. Carries octane from lungs to resourcing cells. Carrier protein.

22
Q

What can gene mutations lead to?

A

Occurs spontaneously. And can cause production of different proteins.

23
Q

How do mutations occur?

A

Spontaneously but can occur more with radiation and chemicals

24
Q

What are the three possibilities of mutations?

A

They can be harmful, beneficial or have no effect

25
Q

How many genes are used in any one cell?

A

Only some ill sets are used as some are switched off.

26
Q

What types of genes determined the functions of a cell?

A

Genes that are switched on

27
Q

How do changes to genes alter the production of protein that is normally made?

A

Changes to gene changes base code of DNA which changes order of amino acid in proteins

28
Q

What is the symbolic equation of aerobic respiration?

A

C6H12O6 + 6O2 -> 6CO2 + 6H2O

29
Q

What happens as the rate of respiration increases?

A

The rate of respiration increase means the oxygen consumption increases. More carbon dioxide is produces.

30
Q

What is the respiratory quotient (RQ)?

A

Carbon dioxide produced/oxygen produced

31
Q

What does the respiration produce, and what is the product used for?

A

ATP is produced and this is the main energy source for many processes in cells

32
Q

What can the rate of oxygen be used for?

A

It can be used to estimate the metabolic rate because aerobic respiration requires oxygen.

33
Q

How is the rate of respiration influenced by changes in temperatures and pH?

A

This happens because of enzyme activity and respiration is controlled by enzymes.

34
Q

Why does anaerobic respiration take place during hard exercise?

A

As muscles need to receive sufficiently gem supply.

35
Q

What does anaerobic reputation produce and what does it cause?

A

It produces lactic acid, and pain and fatigue as it accumulates in the muscle.

36
Q

What is the more equation for anaerobic respiration?

A

Glucose -> lactic acid

37
Q

What is a disadvantage of anaerobic respiration?

A

It released less energy per glucose molecule than aerobic respiration

38
Q

What are the advantages of being multicellular?

A

It allows organisms to be larger. It allows cell differentiation and it allows the organisms to be more complex.

39
Q

What does mitosis produce?

A

It produces new cells for growth.

40
Q

Why are new cells of mitosis genetically

A

The new cells are genetically identical as DNA replication has taken place; each cell produced has two copies of each chromosome.

41
Q

In mammals, body cells are…

A

Diploid - they have two copies of each chromosome

42
Q

Why must DNA replication take place before cells divide?

A

So that each of the cells produced haas two copied of the same chromosome

43
Q

How does DNA replication happen (before mitosis)?

A

Two strands of the DNA molecule unzips to form single strands . New double strands are formed by complementary base pairing

44
Q

What happens in mitosis?

A

The chromosomes line up along the centre od the cell. They then divide. The copies move to the opposite poles of the cells.

45
Q

What does meiosis produce?

A

Gametes

46
Q

What are gametes

A

They are haploid; they contain one set of chromosomes in each pair

47
Q

How does fertilisation result in genetic variation?

A

The games combine to form a diploid zygote. The games on the chromosomes combine to control the characteristic of the zygote.

48
Q

How if the sperm cell adapted for its functions?

A

it has many mitochondria to provide energy. It has an acrosome that releases enzymes to digest the egg membrane

49
Q

How are the structure of the red blood cells adapted to their functions?

A

They are very small meaning they can pass through the smallest blood vessels. They are shaped like a biconcave disk so they have a large surface area to exchange oxygen quicker. They lack nucleus so more haemoglobin can fit in.

50
Q

How is the red blood cells are adapted to their functions

A

It is shaped like a biconcave disc, providing it with a large surface area to volume ratio

51
Q

What does haemoglobin react with to form oxy haemoglobin and how is this reaction irreversible?

A

The haemoglobin in the red blood cells react with oxygen on the lungs to form oxyhaemoglobin. The reaction is irreversible as when this reaches the tissue, the oxygen is released.