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Flashcards in Topic 1 Deck (92)
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1
Q

List the two polysaccharides that make up starch

A

amylose and amylopectin

2
Q

Describe the sequence of events in the cardiac cycle. Name the stages and describe the pressure changes, opening and closing of valves and direction of blood flow through chambers

A

The blood enters the right atrium through the vena cava. This is the atrial and ventricular diastole, as the pressure lowers in the atria the blood flows through into the atria. The atrioventricular valve (tricuspid) is closed at this point, and the semi-lunar valve close as the ventricle relaxes. As the pressure in the atria increases the atrioventricular valves are forced open and the blood flows through into the ventricle, this is the Atrial systole. After a delay the ventricle contracts increasing the pressure and the blood is forced through the semi-lunar valve (pulmonary) into the pulmonary artery. it then returns from the lungs from the pulmonary vein into the left atrium. The heart continues in atrial systole, as the blood passes through the atrioventricular valve (bicuspid) into the left ventricle. The heart then undergoes ventricular systole and the blood passes through the semi-lunar valve (aortic) and into the aorta.

3
Q

Explain how high blood pressure can lead to CVD and myocardial infarction

A

High blood pressure causes strain on the arteries and veins throughout the body, this could be due to atherosclerosis or another disorder. The high pressure could lead to an increase in atherosclerosis or an aneurisms which in turn could cause blockages. This then leads to higher increase of risks to CVD and heart attack

4
Q

Describe the process of blood clotting

A

When a blood vessel is damaged a series of reactions take place which lead to the formation of a blood clot. Thromboplastin is released from the damaged blood vessel. Platelets stick together and form a platelet plug over the wound. The thromboplastin causes the conversion of prothrombin into thrombin. This thrombin catalyses the conversion fibrinogen into fibrin. The fibrin tangles together into a mesh and over the damaged area, causing platelets and red blood cells to be caught and form a blood clot.

5
Q

Describe the sequence of events leading to atherosclerosis

A

As an atheroma develops in the walls of arteries, they have the possibility to rupture. This causes a Thrombosis and the site of the rupture. This blood clot can cause a blockage in the artery, causing the blood flow to the surrounding tissue to be lessened resulting in damage, thus increasing the risk of heart attack and DVT

6
Q

Explain the difference between and monounsaturated, polyunsaturated and saturated lipids

A

monounsaturated: Lipid with only one carbon to carbon double bond.
polyunsaturated: Lipid with more than one carbon to carbon double bond.
saturated: Lipid with no carbon to carbon double bonds

7
Q

State the formula of a Glucose molecule

A

C6H12O6

8
Q

Describe the basic structure of a triglyceride

A

A Glycerol molecule which is attached to three fatty acids via an ester bond

9
Q

Describe how a triglyceride is formed and broken

A

the reaction which takes place during the formation or breaking down of a triglyceride is a condensation reaction. This is due to the formation of an ester bond. To break this bond a condensation reaction occurs.

10
Q

Describe the structure of a water molecule

A

A water molecule is a V-shaped molecule of one oxygen joined by two hydrogen atoms. It is a dipolar molecule, meaning the negatively charged oxygen atom attracts the positively charged hydrogen atom, also known as hydrogen bonding

11
Q

Describe how hydrolysis of maltose occurs and why water is needed

A

The water molecules are required for the hydrolysis of any molecule, as for an ester bond to break a hydrogen atom is required to bond to the molecule still containing a oxygen and the other molecule bonds with a hydrogen and oxygen atoms

12
Q

Why are glycosidic bonds either called 1,4 or 1,6 glycosidic bonds

A

The carbons in Hydrocarbon chains are numbered in a circle. The 1,4 or 1,6 indicate which carbons the glycosidic bonds are between

13
Q

Why do animals have a heart and circulatory system

A

Allows for transportation of blood around the body in a mass flow system, rather than the use of diffusion. Thus oxygen and other minerals can travel around the body

14
Q

Define mass flow

A

The transportation of large amounts of useful minerals and recourses around the body

15
Q

Define diffusion

A

The movement of particles from a region it high concentration to lower concentration

16
Q

Describe the features of a mass flow system

A
  • modes of transportation - blood vessels
  • exchange surface - lungs
  • pump - heart
  • transportation medium - blood
  • one way valves to prevent back flow
17
Q

Describe an open circulatory system

A

Open circulatory systems are made up if chambers which full with blood rather than being stored and transported in blood vessels

18
Q

Describe a closed circulatory system

A

Closed circulatory systems transport blood via vessels and do not fill body cavities

19
Q

Identify key features of a single circulatory system

A
  • two chambers are present in the heart
  • lower blood pressure than double circulatory systems
  • blood only enters the heart once
20
Q

Identify key features of a double circulatory system

A
  • the heart has four chambers, splitting the heart into two section
  • systemic circulation
  • pulmonary circulation
  • higher blood pressure than single circulatory systems
21
Q

State the difference between pulmonary circulation and systemic circulation

A
  • Pulmonary circulation is the circulation of blood to and from the lungs, oxygenating the blood.
  • systemic circulation is the circulation of blood to the body and vital organs.
22
Q

List the structure of arteries, veins and capillaries

A
  • arteries - thick muscular walls with no valves allowing for the blood flows at high speeds and pressure. The blood is rich with oxygen
  • veins - less muscular walls with valves to prevent back flow. The blood is rich with carbon dioxide
  • capillaries - transport blood from arteries to veins. Very small blood vessels, with a cell wall of a thickness of one cell; to allow for easy diffusion of oxygen Into the body
23
Q

Explain why the walls if the ventricles are thicker than the walls of the atria

A

Ventricles have thicker walls than the atria, as the atria only have to pump blood to the ventricles, whereas the ventricles pump blood to the lungs and the rest of the body.

24
Q

Why is the left ventricle thicker than the right ventricle?

A

The aorta, leaving the left ventricle, is part if systemic circulation, which is a much larger area for the blood to travel, requiring more pressure and speed of blood flow. To keep this demand the left ventricle is thicker to pump harder than the right ventricle which undergoes pulmonary circulation.

25
Q

State the three main stages of the cardiac cycle

A

1) diastole
2) atrial systole
3) ventricular systole

26
Q

What causes the valves to open and close

A

The build up In pressure causes the valves to open and close.

As the pressure in the ventricle is higher than that of the atrium, the atrioventricular valve closes, but as the pressure builds higher than the artery, the semi-lunar valve opens.

27
Q

Define a myocardial infarction

A

Medical/biological name of a heart attack. Caused when blood does not flow effectively to the heart, and the heart muscle is damaged due to the lack of oxygen, eventually causing the tissue to die

28
Q

Define a stroke

A

A stroke is the loss of brain function due to a disruption of blood reaching the brain. The lack of oxygen causes the brain cells to begin to die

29
Q

Define an angina

A

Angina is chest pain caused by obstruction or a spasm oft he coronary arteries, thus the pain is caused as the heart works harder to pump more blood to the body

30
Q

Define an aneurysm

A

An aneurysm is a ballon shaped bulge filled with blood in the side of an artery.

31
Q

Define thrombosis

A

Thrombosis is medical/biological name given to blood clotting and is the formation of blood clots in blood vessels

32
Q

Define hypertension

A

Hypertension, or high blood pressure, is a condition where the blood pressure in the arteries rises.

33
Q

Define systolic pressure and diastolic

Pressure

A

During a heartbeat, the pressure of the blood varies. It is measured at its maximum, systolic, and minimum, diastolic.

34
Q

Define sphygmomanometer

A

A sphygmomanometer is a device used for measuring blood pressure

35
Q

What is the normal range of blood pressure in adults

A

90/50 to 120/90

36
Q

Define a monosaccharide

A

The most basic carbohydrate unit, comprising of a single carbohydrate molecule

37
Q

Define a disaccharide

A

A carbohydrate unit, made up from two carbohydrate molecules

38
Q

Define a polysaccharide

A

A carbohydrate unit made from three or more carbohydrate molecules

39
Q

What compound is needed for a hydrolysis reaction between saccharides and why?

A

Water - H2O

The water is needed to break down the two hydroxyl groups on the sugars, to form an ester link or glycosidic bond

40
Q

What compound is needed for a hydrolysis reaction between saccharides and why?

A

Water - H2O

The water is needed to break down the two hydroxyl groups on the sugars, to form an ester link or glycosidic bond

41
Q

Name 1 monosaccharide

A

Glucose

42
Q

Name 3 disaccharides

A

Maltose, lactose, sucrose

43
Q

Name 3 polysaccharides

A

Amylopectin, amylose, glycogen

44
Q

Describe how amylose is beneficial for the storage of starch

A

The angles of the glycosidic bonds give it a coiled structure. This makes it more compact, so it is good for storage because you can fit more into a small space

45
Q

Describe how amylopectin is beneficial for the storage of starch

A

Its side beaches allow the enzymes that break down the molecule to get at the glycosidic bonds easily. This means that the glucose can be released quickly

46
Q

Why is starch good for storage?

A

It is insoluble in water, so doesn’t cause water to enter cells my osmosis (which would make them swell)

47
Q

Describe the structure of triglyceride

A

1 glycerol molecule with 3 fatty acids attached to it. These are joined together by ester bonds

48
Q

Describe how triglyceride is formed

A

This is a condensation reaction

A hydrogen at on the glycerol molecule bonds to a hydroxyl group on the fatty acid, releasing a water molecule

49
Q

Describe how triglyceride is broken up

A

This is hydrolysis

A molecule of water is added to each ester bond in triglyceride to break it apart

50
Q

What do antihyoertensives do and what are the benefits and risks?

A

Reduces blood pressure
Benefits - different types work in different ways, so they can be given in combination. Blood pressure can be measured at home, so the patient can see if the drugs are working

51
Q

What do plant statins do and what are the benefits and risks?

A

Reduce cholesterol in the blood
Benefits - reduce the risk of developing CVD
Risks - can reduce the absorbtion of some vitamins from the gut

52
Q

What do anticoagulants do and what are the benefits and risks?

A

They reduce the formation of old clots
Benefits - can be used to treat people who already have blood clots or CVD
Risks - if a person taking the drugs is seriously injured, the reduction in blood clotting can lead to excessive bleeding. Can also damage the fetus if taken during pregnancy

53
Q

What do platelet inhibitory drugs do and what are the benefits and risks?

A

They reduce the formation of blood clots
Benefits - they can be used to treat people who already have blood clots or CVD
Risks - if a person taking them has a serious injury, reduction of blood clots can lead to excessive bleeding. Side effects also include rashes and nausea

54
Q

How can an imbalance in energy can lead to weight gain?

A

If energy intake is higher than energy output, the excess energy will be turned into fat reserves by the body so the person will gain weight
If energy difference is a lot and sustained over a long period of time, the person could become obese

55
Q

Describe how an imbalance in energy can lead to weight loss

A

If energy intake is lower than energy output, the body will have to get more energy from somewhere, so it’ll turn some of its fat reserves into energy, so the person will lose weight
If this energy difference is large and sustained over a long period of time, the person is likely to become underweight

56
Q

What are membranes composed of?

A

Lipids, proteins and carbohydrates

57
Q

Describe how scientific evidence led to the fluid mosiac model of the cell membrane

A

Before the 1970s, most scientists believed cell membranes were composed of a phospholipid layer between 2 continuous layers of proteins. This was because electron microscope images appeared to show 3 layers in a cell membrane
In time, improved electron microscope techniques showed a bilayer of phospholipids, and new methods for proteins showed that they were randomly distributed in cell membranes, not a continuous layer
Scientists also carried out experiments that proved the cell membrane is a fluid

58
Q

What is osmosis?

A

The movement of free water molecules through a partially permeable membrane

59
Q

Describe the mechanism of action of specificity of enzymes

A

Enzymes are very specific and usually only catalyse one reaction
This is because only one substrate will fit into the active site
The active sight’s shape is determined by the enzyme’s 3D structure, which is determined by the enzyme’s primary structure
Each different enzyme has a different 3D structure and so a different shaped active site. If the substrate shape doesn’t match the active site, the reaction won’t be catalysed
If the 3D structure of a protein is altered in any way, the shape of the active site will change. This means the substrate won’t fit into the active site and the enzyme will no longer be able to carry out it’s function

60
Q

What are enzymes?

A

Globular proteins

They are biological catalysts that reduce activation energy

61
Q

DNA and RNA are…

A

Polynucleotides - they are made up of lots of mononucleotides joined together

62
Q

What are mononucleotides is made from…

A

A pentose sugar, a phosphate group and a nitrogenous base

63
Q

What are the 4 possible bases of DNA?

A

Adenine, thymine, cytosine, guanine

64
Q

What are the 4 possible bases of RNA?

A

Adenine, uracil, cytosine, guanine

65
Q

How is a DNA double-helix formed

A

2 complementary DNA strands join together by hydrogen bonding between the bases
The 2 DNA strands wind up to form the DNA double-helix

66
Q

What are the complementary pairings of bases?

A

Adenine and thymine

Guanine and cytosine

67
Q

Describe DNA replications

A

The DNA helix unzips to form 2 single strands
Free-floating mononucleotides join to each original strand by complementary base pairing
The mononucleotides on the new strand are joined together by the enzyme DNA polymerase. Hydrogen bonds form between the bases on the original and new strand
Each new DNA molecule contains 1 strand from the original DNA molecule and 1 new strand
This is semi-conservative replication

68
Q

Describe Meselson and Stahl’s experiment and how is provides evidence for semi-conservative replication

A

2 samples of bacteria were grown, one in a nutrient broth containing light nitrogen, one in a broth containing heavy nitrogen. As the bacteria reproduced, they took up nitrogen from the broth to help make mononucleotides for new DNA. So the nitrogen gradually became part of the bacteria’s DNA
A sample of DNA was taken from each batch of bacteria, and spun in a centrifuge. The DNA from the heavy nitrogen bacteria settled lower down the centrifuge tube than the DNA from the light nitrogen bacteria, because it’s heavier
Then the bacteria grown in the heavy nitrogen broth were taken out and put in a broth containing only light nitrogen. The bacteria were left for 1 round of DNA replication, and then another DNA sample was taken out and spun in the centrifuge
The DNA settled out in the middle, showing that the DNA molecules contained a mixture of heavy and light nitrogen. The bacterial DNA had replicated semi-conservatively in the light nitrogen
This disproved DNA replication as conservative

69
Q

What is a gene?

A

A sequence of bases on a DNA molecule that codes for the sequence of amino acids on a polypeptide chain

70
Q

What determines the order of amino acids in a protein?

A

The order of mononucleotide bases in a gene

71
Q

Describe the first stage of protein synthesis

A

Transcription
The hydrogen bonds between the 2 DNA strands in a gene break, separating the strands, and the DNA molecule uncoils
One of the strands is then used as a template to make an RNA copy, called messenger RNA. The template strand is called the antisense strand
Free RNA mononucleotides line up alongside the template strand. Once the RNA mononucleotides have paired up with their complementary bases on the DNA strand they’re joined together, forming and mRNA molecule
The RNA moves out of the nucleus through a nuclear pore, and attaches to a ribosome in the cytoplasm
Once enough mRNA has been produced, the hydrogen bonds between the uncoiled strands of DNA reform, and the strands cool back into a double helix

72
Q

Describe the second stage of protein synthesis

A

Translation
This occurs in the cytoplasm
The mRNA attaches itself to a ribosome and transfer RNA molecules carry amino acids to the ribosome
A tRNA molecule, with complimentary bases to the first triplet of bases on the mRNA, attaches itself to the mRNA by complementary base pairing
A second tRNA molecule attaches itself to the next triplet of bases on the mRNA in the same way
The 2 amino acids attached to the tRNA molecules are joined together by a peptide bond. The first tRNA moves away, leaving it’s amino acid behind
A third tRNA molecule binds to the next triplet on the mRNA. it’s amino acid binds to the first 2 and the second tRNA molecule moves away
This process continues, producing a chain of linked amino acids (a polypeptide chain), until there is a stop signal on the mRNA molecule
The polypeptide chain moves away from the ribosome and translation is complete

73
Q

How can errors in DNA replication lead to mutation

A

Mutations are changes to the base sequence of DNA

74
Q

Substitution

A

One base is substituted with the other

75
Q

Deletion

A

One base is deleted

76
Q

Insertion

A

An extra base is added

77
Q

Duplication

A

One or more bases are repeated

78
Q

Inversion

A

A sequence of bases is reversed

79
Q

Allele

A

A different version of a gene. Most plants and animals have 2 copies of each gene, one from each parent. The 2 copies can be the same or they can be different. Different versions have slightly different base sequences, which code for different versions of the same characteristic. Eg brown eyes and blue eyes

80
Q

Genotype

A

The alleles a person has

Eg BB, bb, Bb for eye colour

81
Q

Phenotype

A

The characteristics the alleles produce

82
Q

Dominant

A

An allele whose characteristics appear in the phenotype even when there only one copy

83
Q

Recessive

A

An allele whose characteristic only appears in the phenotype if 2 copies are present

84
Q

Homozygote

A

An organism that carries 2 copies of the same allele

85
Q

Heterozygote

A

An organism that carries 2 different alleles

86
Q

Carrier

A

If a recessive allele can cause a disease, a carrier is someone who has one dominant and one recessive allele. They won’t have the disease but they carry a copy of the allele for the disease

87
Q

Is the allele for a smooth seed dominant or recessive?

A

Dominant (S)

88
Q

Is the allele for a wrinkled seed dominant or recessive?

A

Recessive (s)

89
Q

Is the allele for tall plants dominant or recessive?

A

Dominant (T)

90
Q

Is the allele for dwarf plants recessive or dominant?

A

Recessive (t)

91
Q

Is the allele for cystic fibrosis recessive or dominant?

A

Recessive (f)

92
Q

Is the allele for thalassaemia recessive or dominant?

A

Recessive (t)