Unit 2: Food and Health Flashcards
(130 cards)
0
Q
What are nutrients needed for?
A
Better health
Stronger immune system
Learn more effectively
To increase productivity
1
Q
What is a balanced diet?
A
Provides all nutrients and energy needed to sustain life
2
Q
What are the 7 main food groups and what do they provide for the body?
A
Carbohydrate-main source of energy
Proteins-growth and repair of muscle and tissues
Fats-biggest source of energy, cell membranes, waterproofing, absorption of fat soluble vitamins
Vitamins-roles in chemical processes
Minerals- inorganic elements essential to normal functions
Water-transporting substances around body
Fibre-essential for healthy functioning of digestive system
3
Q
What does changes to weight show about energy in the diet?
A
Losing weight= too little energy in diet
Gaining weight= too much energy in diet
4
Q
What are the body categories for BMI?
A
Less than 18.5 = underweight 18.5-25= healthy 25-30= overweight 30-35=obese (class 1) 35-40= obese (class 2) Over 40= morbidly/ severely obese (class 3)
5
Q
Why is BMI not an accurate measure of body mass?
A
Person may be pregnant
Person may have lots of muscle-make them heavier than average person
BMI not suitable for children
6
Q
What is obesity?
A
When the body weight of a person is 20% or more above the weight recommended for your height
7
Q
Why is obesity classed as a form of malnutrition?
A
The person is not getting the right amounts of each food group
Increased amounts of fatty foods
Little exercise
Social and economic stress lead to comfort eating
Physiological problems eg underactive thyroid gland
8
Q
What diseases are so societies with obesity?
A
Coronary heart disease High blood pressure Angina (sufficient blood flow to heart but coronary arteries can't cope with exercise, results in chest pains) Varicose veins Type 2 diabetes Osteoarthritis Gall stones
9
Q
How is salt linked to heart disease?
A
Salt-excess salt levels decrease water potential of blood=high diastolic pressure
- > hypertension
- > damage to artery walls, starting atheroscerlosis leading to HD
10
Q
How is fat linked to heart disease?
A
Balance of fats needed (sat fats and unsat fats)
An excess of sat fats can lead to atheroscerlosis, leading to HD
11
Q
What is the difference between low density lipoproteins and high density lipoproteins?
A
LDL= sat fat, cholesterol and protein HDL= unsat fat, cholesterol and protein
12
Q
How are polyunsaturated fats and monounsaturated fats useful to us?
A
Polyunsaturated fats=increase the number of receptors available for LDLs so more cholesterol enters tissues
Monounsaturated fats=remove LDLs from blood
13
Q
Short term effects of tar? (4)
A
Settles in airway and alveoli linings- increases diffusion distance for gaseous exchange
Chemicals in tar can cause allergic reactions-causes smooth muscle contract
Tar paralyses/destroys cilia and stimulates goblet cell production
Trapped bacteria in mucus means lungs more susceptible to infection
14
Q
Long effects of tar? (3)
A
Smokers cough
Frequent infections
Lung cancer
15
Q
What does a smokers cough do to the airways?
A
Caused by tar irritating the airways and the need to clear blocked airways
- > Cough damages airway and alveoli lining which gets replaced with scar tissue=thicker and less flexible
- > layer of smooth muscle in bronchioles thickens, lumen narrows and flow of air permanently restricted
16
Q
How do frequent infections, caused by smoking, result in damage to lining and layer of epithelium?
A
Infections attract WBC to deal which pathogens
- WBC have to enter airways
- to enter airways, enzyme used to break through lining walls (elastase), damaging elastic tissue of lining of lungs
17
Q
How does smoking cause lung cancer?
A
Cigarettes contain carcinogenic compounds which cause cancer-found in tar lying on surface of lungs
Carcinogens enter lung tissue cells, enter nucleus and mutate the genetic material
-> if mutation affects genes for cell division, leads to uncontrollable cell division
18
Q
Where does lung cancer often start developing?
A
At the entrance to the bronchi as this is where smoke deposits tar in the airways
19
Q
Why are cancers difficult to detect?
A
Lung cancer can take 20-30 years to develop, meaning it might be years before the cancer is actually discovered
20
Q
Name 4 diseases associated with smoking
A
Chronic bronchitis
Emphysema
Chronic obstructive pulmonary disease
Lung cancer
21
Q
What are the causes and symptoms of chronic bronchitis?
A
Causes= inflammation of airways with damage to cilia and overproduction of mucus lead to mucus collecting in lungs
Symptoms= lung irritation, continued coughing, coughing up mucus with bacteria and WBC
22
Q
What are the causes and symptoms of emphysema?
A
Causes=loss of elasticity in alveoli causing alveoli to burst -> decreases SA for gaseous exchange
Symptoms=shortness of breath especially when exerting themselves, in extreme cases breathing is shallow and rapid leading to fatigue
23
Q
What is chronic obstructive pulmonary disease?
A
Combination of chronic bronchitis emphysema and asthma
24
What are the symptoms of lung cancer?
Continual coughing, shortness of breath, chest pain and blood coughed up in sputum
25
What effect does nicotine have on smokers?
It's the addictive chemical. The smoker gets used to the effects and becomes addicted.
26
What are the specific effects of nicotine on a smoker and why?
Increased sensitivity, feel more alert-nicotine mimics action of transmitter substances at synapses between nerves
Increased blood pressure-nicotine releases adrenaline, increased heart rate and constriction of arterioles
Restricted blood flow to extremities-nicotine causes constriction of arterioles=decreased blood flow and oxygen delivery
Increased risk of blood clot or thrombus-nicotine makes platelets more sticky
27
What effect does carbon monoxide have on smokers?
Decreases affinity for oxygen
Forms carboxyhaemoglobin (more stable and combines more readily than oxygen)
Lower oxygen levels may cause heart rate to rise
Can also damage lining of arteries
28
Name 4 problems caused by changes to blood system
Atheroscerlosis
Thrombosis
Stroke
Coronary heart disease
29
How des athersclerosis occur?
Carbon monoxide can damage the inner lining of the arteries, this is worsened by high blood pressure
Movement of WBC plus high blood pressure causes deposition of LDLs in arteries
Deposits (atheromas) May include fibres, dead BCs, platelets- this process is called atherosclerosis
30
Where do atheromas build up?
Build up inside artery wall, under endothelium and form a place that sticks out into the lumen
-> wall becomes rougher and less flexible, lumen becomes smaller decreasing blood flow
31
How does thrombosis form? What effect can it have on blood flow?
Blood flowing past an area of plaque is more likely to clot, especially if platelets are more sticky (a side effect of nicotine)
If blood exposed to plaque->exposed to fatty deposits = blood clot
Clot can stop blood flow-> Clot or part of one can be carried in blood, can lodge in narrow artery
32
How does a stroke occur and what is the cause?
Caused by loss of blood flow to brain-can be vr sudden
Blood clot can block small arteries leading to brain
Or
Artery leading to brain bursts (haemorrhage)
33
What is the cause of CHD (coronary heart disease)?
Lumen of coronary arteries narrowed by plaque=decreased blood flow=less oxygen for respiration
Coronary arteries branch off close to heart carrying blood at high pressure
-> prone to damage and atheroscerlosis
34
What 3 forms can CHD take?
Angina-severe chest pain, may extend into neck/down left arm
Heart attack-death of heart muscle (usually caused by blocked coronary artery)
Heart failure-heart can't sustain pumping action due to blockage of major coronary artery
35
What are cardiovascular diseases?
Diseases that affect the heart and circulatory system
36
What is arteriosclerosis?
Deposition of minerals eg calcium in hue lining of the artery: they become less elastic and less flexible
37
What is the difference between arteriosclerosis and atherosclerosis?
Arteriosclerosis=hardening of artery walls
| Atherosclerosis=build up of fatty deposits in artery walls
38
What is a risk factor?
Something that contributes to the development of a disease
39
Name at least 4 risk factors for CHD
```
Age-risk increases as age does
Sex-more common in males
High blood pressure/cholesterol concentration
Smoking
Obesity
High animal fat/salt intake/Absence of healthy fats
Physical inactivity
Genetic factors
Stress
Diabetes
```
40
Why is CHD more common in MEDCs?
Fatty foods and cigarettes more readily avaliable
41
What is epidemiology?
Study of distribution of a disease in populations and factors that influence it's spread
42
What factors will be considered in an epidemiology study?
Who is most at risk? Eg country, age group, sex, lifestyle factors
43
Using epidemiology, how has smoking been linked to lung cancer?
25% smokers die of lung cancer
| Smoker x18 and heavy smokers x25 more likely to develop lung cancer than non-smokers
44
Using epidemiology, how has smoking been linked to lung diseases?
COPD rare in non-smokers
30% smokers have emphysema
98% of all people with emphysema are smokers
45
Why is it difficult to link Cardiovascular disease and smoking?
CD has many risk factors, not just smoking
46
What is health? (WHO definition)
A state of complete mental, physical and social well being and not merely the absence of disease and infirmity
47
What is disease?
Anything that impairs the normal functioning of the body and that leads to a departure from good health
48
How is HIV caused?
By Human immunodeficiency virus
- enters body, remains inactive (host is HIV-positive)
- becomes active, attacks T helper lymphocytes vital to immune system
- > leads to contraction of other disease eg skin cancer, pneumonia, TB
49
How is HIV transmitted?
```
Exchange of bodily fluid
Unprotected sex
Unscreened blood transfusion
Unsterilised surgical equipment
Sharing of hypodermic needles
'Needle-stick' accidents
Across placenta in birth
From mother to baby in breast feeding
```
50
How can HIV cases be reduced?
Free condoms
Education
Provide clean needles for drug addicts
Use drugs for early diagnosis-target at-risk groups
51
How is TB caused?
Mycobacterium tuberculosis bacteria reaches alveoli, not damaged by macrophages
-> divide and release new bacterium
Spreads to new cells
Causes tissue damage in lungs and rest of body
Leads to night sweats, weight loss, coughs/coughing up blood and likely death
52
How is TB transmitted?
Infected person breathes out bacteria in droplets
```
Need close proximity eg sleeping in crowded conditions/poor ventilation
Malnutrition
Living with people from infected areas
HIV and weakened immune system
Milk/meat of infected cattle
```
53
Why are TB cases increasing?
Antibiotic courses long and not always completed
Mutated forms of bacteria resistant to vaccines
Lack of education
80% people are carriers but unaware
Poorer areas/countries can't afford vaccine
54
What is a vector (in terms of disease)?
A carrier for disease
55
Name 1 species of plasmodium that can carry malaria
P. Vivax
P. Ovale
P. Falciparum
P. Malariae
56
How is malaria transmitted from person to person?
Person with malaria bitten by mosquito-sucks parasite gametes into stomach
Gametes fuse-zygotes develop in stomach then move to salivary glands
Mosquito bites healthy person-saliva injected as coagulant (blood doesn't clot)
Saliva contains active stage of parasite
In human host, infective stages enter liver, multiply, pass into blood
In blood, enter RBC feed on haemoglobin protein, gametes produced
THE CYCLE CONTINUES...
57
How can malaria be prevented?
Drugs to prevent infection
| Nets and repellents cheap method
58
What is immunity?
Protection against disease provided by the body's defence or immune system
59
What are primary defences?
Ones which attempt to prevent pathogens entering the body
60
Describe the process of keratinisation
Epidermis contains keratinocytes cells
Keratinocytes produced by mitosis at base of epidermis and migrate towards surface
Cells dry out and die as they migrate, cytoplasm eventually replaced by keratinocytes
Layer of dead cells acts as effective barrier to pathogens
61
How do the ciliated epithelium and goblet cells act as part of our primary defences?
Goblet cells produce mucus and traps pathogens
Ciliated epithelium have cilia which waft mucus up airway towards back of throat, gets swallowed into stomach where any pathogens get broken down by acidic conditions
62
Name 3 examples of primary defences
Eyes protected by antibodies in tear fluid
Ear Canal lined with wax
Vagina protected by acidic conditions
63
What happens if pathogens make it past our primary defences?
Phagocytes released as a secondary defence
| -kill pathogens before they can reproduce and cause disease
64
What are neutrophils?
Most common phagocytes, produced in bone marrow
Travel in blood (sometimes in tissue fluid)
Also found on epithelial surfaces
Short-lived but released in large numbers
65
What are macrophages?
Larger cells, made in bone marrow
Travel in blood as monocytes (large, phagocytic WBC)
Tend to settle in body organs, particularly lymph nodes where they develop into macrophages
Important role in specific immune response
66
How do phagocytes work?
Pathogens have anti-gens (chemical markers on outer membrane)- specific to them, identify as foreign
Foreign antigens trigger anti-body response and attach to foreign antigens
Phagocytes have receptors (membrane bound proteins) which attach to anti-bodies
Pathogen engulfed and digested by lysosomes, releasing harmless digestion products
67
Why a happened to neutrophils after ingesting a few pathogens?
Since they are often short lived, they may die
| -collect in an infected area as pus
68
What happens when infected cells release the chemical histamine?
Neutrophils attracted to the cell and capillaries become more leaky
- more fluid leaves capillaries=redness and swelling
- more tissue fluid enters lymphatic system-pathogens led towards macrophages in lymph nodes
69
What is an anti-gen?
Large molecules that have a specific shape and can stimulate an immune response
70
What is an anti-body?
Molecules produced by the lymphocytes in the immune system
71
How are antibodies specific to particular bacteria?
They have complementary shapes to a particular antigen
72
Describe the shape of an antibody?
4 polypeptide chains (2 heavy, 2 light) joined by disulfide bridges
Constant region-same in all antibodies
Variable region-septic shape
Hinge regions-allow for some flexibility
73
What are the roles of the constant, variable and hinge regions?
Constant-enables antibody to attach to phagocytic cells and help phagocytosis
Variable-different amino acid sequence means complementary shape to right antigen
Hinge-allows branches of y-shaped molecule to move further apart->allows more than one antigen to attach
74
How do antibodies kill pathogens?
Neutralise by blocking antigens-unable to bind to host cell
Larger antibodies (look like many y-shaped molecules joined together) with many specific regions can attach to a number of pathogens at one time=agglunation
75
How do primary and secondary immune response differ?
Primary (infected first time)
- over a few days, number of antibodies begins to rise slowly
- once pathogen is dealt with, antibodies in blood decreases
Secondary (infected a second time)
- immune system acts much more quickly
- concentration of antibodies rises sooner, reaches a higher concentration
76
What is a vaccination?
Deliberate exposure to antigenic material which activates the immune system to make an immune response and provide immunity
77
What forms of vaccination are there?
- whole, live microorganisms eg smallpox vaccine
- harmless version of pathogenic material eg TB
- dead pathogens eg typhoid
- preparation of antigens from pathogen eg hepatitis B
- a harmless toxin (toxoid) eg tetanus
78
How does the body react to a vaccine?
Immune system produces antibodies and memory cells in response to pathogenic material
-provides long term immunity
79
What is a herd vaccination?
Provides immunisation to almost all at risk
| Once enough are vaccinated disease can no longer spread and dies out
80
What is a ring vaccination?
If a new disease is reported, all in immediate vicinity of new cases are vaccinated
Used in livestock diseases eg foot and mouth disease
81
How could the influenza virus become a potential threat in the future?
If new strains appear resistant to vaccination, may cause epidemic (affects large population) or pandemic (spreads worldwide/over continents)
To avoid, people most at risk may be immunised
Eg in uk where flu vaccination changes each year
82
What is active immunity?
| What forms can it take?
Immunity developed after contracting pathogens inside the body
Natural-infection
Artificial-injection of live/attenuated pathogen
83
What is passive immunity?
| What forms can it take?
Immunity provided by antibodies or antitoxins provided outside the body
Natural-antibodies from mothers milk/across placenta
Artificial-injection of antibodies or antitoxins
84
What is artificial immunity?
Immunity required as a result of deliberate exposure to antigens or injection of antibodies
85
What is natural immunity?
Immunity acquired hot rough exposure to disease during the normal course of life
86
How do plants make food?
Photosynthesis
Most plants store energy as carbohydrate stretch
Can absorb minerals from soil and other biological molecules
87
What is a herbivore?
An animal that eats plant material
88
What is an omnivore?
An animal that eats plant and animal material
89
How can we increase food production in plants?
```
Improve growth rate
Increase size of yield from each plant
Decrease crop loss due to disease/pests
Make harvesting easier by standardising plant size
Improve plant response to fertilisers
```
90
How can food production in animals be improved?
Improve rate of growth
Increase productivity
Increase resistance to disease
91
What is selective breeding?
Where humans select the individual organisms that are allowed to breed according to chosen characteristics
92
What are the 3 stages of selective breeding?
Isolation
Artificial selection
Inbreeding/line breeding
93
How can we increase efficiency in selective breeding?
Detailed records of breeding to help selection
Marker assisted selection-section of DNA used as a marker to recognise a characteristic, offspring checked for this marker
-allows early selection
94
Give an example of animal selective breeding
Cattle bred for greater milk yield or meat production-dairy cows can produce 40+ litres a day
Farmed salmon grow quicker, greater disease resistance and meat quality improved (less fatty), better colour and texture
Chickens bred for egg/meat production-egg layers can produce up to 300+ eggs a year
95
Give an example of plant selective breeding
Tomatoes with greater disease resistance
Apples with improved resistance, flavour and texture
96
How do we use chemicals in food production? (3)
Fertiliser-increases fertility by providing minerals for plant growth
eg Mg+=chlorophyll, NO2+=proteins, K+=flowers
Pesticides-chemicals that kill pests
Eg Funghicides=kill funghi
Antibodies-chemical kills/prevents production of bacteria
97
What 4 main ways can microorganisms spoil food?
Visible growth on food
Food reduced to mush by action of enzymes
Toxins in bacteria growing on food
Prescience of microorganisms can cause infection
98
How does cooking prevent food spoilage?
It denatures enzymes and proteins within bacteria
99
How does pasteurising prevent food spoilage?
Involves heating to 72c for 15s then cooling to 4c
| -kills harmful microorganisms
100
How does drying, salting and coating in sugar prevent food spoilage?
Water leaves via osmosis, dehydrates microorganisms
101
How does smoking prevent food spoilage?
Food develops a hard,dry outer layer and smoke has antibacterial chemicals
102
How does pickling prevent food spoilage?
Acidic pH denatures enzymes and other proteins in microorganisms
103
How does irradiation prevent food spoilage?
Ionising radiation disrupts DNA structure of microorganisms
104
How does cooking and freezing prevent food spoilage?
Slows enzyme activity-metabolism, growth and reproduction slowed
105
How can packaging be used to prevent food spoilage?
Canning-airtight seal
Vacuum wrapping-air excluded, microbes can't respire aerobically
Plastic/paper packaging
106
How is yogurt made?
Lactobacillus bacteria
- uses lactose sugar in milk to make lactic acid-> milk protein thickens
- bacteria partially digest milk=easily digestible for humans
107
How is cheese made?
Curdled milk
-lactobacillus act on curds (solid part of milk)
-can make blue cheese by contaminating with penicillium
108
How is bread made?
Aerobically respiring yeast produce co2
| -gas collects in dough and causes it to rise
109
How is alcohol made?
Anaerobic respiration of yeast
- for beer: maltose sugars in cereal grains respired by yeast
- for wine: fructose and glucose sugars in grapes respired by yeast
110
What is mycoprotein?
A protein made from fungus (Fusarium Venenatrium)
111
What are the advantages to mycoprotein?
- faster than plant/animal proteins
- production can be increased/decreased due to demand
- no animal welfare issues
- good source of protein for vegetarians
- no animal fat/cholesterol
- production can be combined with removal of waste products
112
What are the disadvantages to mycoprotein?
- people might not want to eat it
- grown in huge fermenters and need to be isolated
- protein needs purification
- conditions for fungus also ideal for pathogens
- protein doesn't have taste/texture of traditional protein sources
113
What is a parasite?
An organism that lives in/on another organism, causing harm by taking nutrition form the host
114
What is a pathogen?
An organism that causes disease by taking nutrition from a host, causing damage in the process
115
How do bacteria cause disease?
They reproduce rapidly in the body and damage cells by releasing toxic waste products
-eg TB (mycobacterium tuberculosis bacteria)
116
How do viruses cause disease?
They invade cells and take over genetic mechanism and organelles to produce more copies of itself
-host eventually bursts and releases more virus
Eg HIV/AIDS
117
How do funghi cause disease?
Lives in skin and sends out reproductive hypae (strands making up the body of the fungus)
Spores are released at the skin surface
-can cause redness and severe irritation
Eg athletes foot/ringworm caused by tinea microsporum
118
How do protocists cause disease?
Entering host cells and feeding on contents as they grow
Eg malaria
119
How are disease transmitted?
```
Pathogens travel from one host to another
Enter host tissue
Pass through any defences in the body
Reproduce
Damage host tissue
```
120
What are the most common forms of transmission?
Through a vector (any organism that carries pathogens from one host to another)
Through physical contact
Through droplet infection
121
Give the 3 main reasons new drugs needed
New disease emerging
Still many disease without effective treatment
Microorganisms evolving with increased resistance
122
Why is streptomycin rarely used nowadays to make antibiotics?
Most bacteria is now resistant to it
123
How did Fleming discover antibiotics?
He left a Petri dish by an open window before going away
| When he returned he found penicillium mould growing the dish
124
What is meant by transitional medicines?
| -how much of our drugs come from these?
Medicines made from plants
| -80%
125
What is the most common use of poppies in medicine? How does this work?
Opium from poppies is used as an anaesthetic
- works as opiate drugs decrease nervous action in the central nervous system
- > if nerves can't carry nerve impulses no pain is felt
126
How has observing animals given us an insight into new medicines?
Monkeys and bears rub citrus oils onto their coats
-insecticides and antiseptics
Chimps swallow leaves folded in a particular way
-removes parasites from digestive tract
Elephants will roam for miles to find a clay that counteracts dietary toxins
127
Why do biologists want to study the bacterium streptomyces?
To find out what its genes do and potentially develop current production methods of HIV vaccination
128
How are pharmaceutical companies using cell surface receptors to find a new HIV vaccine?
HIV uses CD4 receptor which can be isolated and sequenced
- once we know he amino acid sequence, molecular modelling can be used to determine the receptor shape
- can create a drug to block that receptor without causing major side effects
129
How can sequencing the CD4 or other receptors help vaccine technology?
Once the tech is developed, we can compare human and plant/microorganism DNA
- this could help identify potential medicinal drugs
- could help develop vaccines, by sequencing the genes of microorganisms
- > can help us find a range of candidates from which new drugs can be made
