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Lolo > Biology - Saturday 8th April > Flashcards

Biology - Saturday 8th April Flashcards

1
Q

The heart is an organ that pumps blood around the body in a double circulatory system. What does this mean?

A

Two circuits:

heart —> lungs —> heart

heart —> body —> heart

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2
Q

What are the three types of blood vessels?

A

Vein - wide lumen, valves

Artery - narrow lumen, thick wall (muscle, elastic fibres)

Capillary - thin, one cell thick wall

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3
Q

How are the arteries adapted for their function?

A

Thick walls made of muscle and elastic fibres.

The muscle helps the arteries withstand high blood pressure.

The elastic fibres allow the arteries to stretch and recoil.

They have a narrow lumen, maintaining high blood pressure.

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4
Q

How are the capillaries adapted for their function?

A

Their walls are only one cell thick - super thin, to allow a short diffusion distance, to speed up the rate of diffusion and active transport of substances across their walls.

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5
Q

How are the veins adapted for their function?

A

Thin walled, with very wide lumen. The wide lumen lowers the resistance to the blood flow.

They have valves to prevent backflow of blood.

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6
Q

What controls the natural resting heart rate?

A

A pacemaker in the right atrium of the heart.

Sinoatrial Node: The natural pacemaker that sits in the right atrium in the heart and controls the heart rate, by making the heart contract when it releases an electrical signal

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7
Q

Describe the 4 components of blood

A

Red blood cells

White blood cells

Platelets

Plasma

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8
Q

What is the role of the plasma?

A

Transport of carbon dioxide, digested food, urea, hormones and heat energy.

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9
Q

How are red blood cells adapted for their function?

A

Function of RBCs: Transport oxygen around the body

Biconcave shape - increases its surface area to volume ratio

Absence of nucleus - more space to fit more haemoglobin in

Presence of haemoglobin - this is what the oxygen binds to

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10
Q

What is function of platelets?

A

Platelets cause blood clotting - to prevent blood loss and prevent the entry of pathogens.

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11
Q

What are the two types of white blood cells?

A

Lymphocytes - Produce antibodies and antitoxins

Phagocytes - Engulf (eat and digest) pathogens

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12
Q

What do antibodies do?

A

Antibodies bind to the antigen on the pathogens to help destroy them.

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13
Q

What are the different tissues in a plant, in order from top of the leaf to the bottom of the leaf.

A

Waxy cuticle = Prevent water loss by evaporation

Upper epidermis

Palisade mesophyll = Photosynthesis, so it’s packed with chloroplasts

Spongy mesophyll (= Gas exchange, so it has airspaces) + xylem + phloem

Lower epidermis - stomata, guard cells

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14
Q

What is the function of the palisade mesophyll?

What is the function of the spongy mesophyll?

What is the function of the xylem?

What is the function of the phloem?

What is the function of the guard cells?

A

What is the function of the palisade mesophyll?

Photosynthesis - Therefore it’s packed with chloroplasts with chlorophyll

What is the function of the spongy mesophyll?

Gaseous exchange - Therefore it has air spaces, creating a high surface area to volume ratio

What is the function of the xylem?

Transport of water and dissolved mineral ions, from the roots to the rest of the plant.

What is the function of the phloem?

Transport of sucrose and amino acids, from the leaves to the rest of the plant.

What is the function of the guard cells?

They surround the stomata, and open or close them. They open to allow the movement of carbon dioxide and oxygen in and out of the leaf. They might close to prevent water loss.

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15
Q

What is the definition of a pathogen?

A

Pathogens are microorganisms that cause infectious disease. Pathogens may be viruses, bacteria, protists or fungi. They may infect plants or animals and can be spread by direct contact, by water or by air.

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16
Q

How do bacteria and viruses make us ill?

A

Bacteria and viruses may reproduce rapidly inside the body.

Bacteria may produce toxins that damage tissues and make us feel ill.

Viruses live and reproduce inside cells, causing cell damage.

17
Q

What is (TMV) Tobacco Mosaic Virus? What does it do?

A

Tobacco mosaic virus (TMV) is a widespread plant pathogen affecting many species of plants including tomatoes. It gives a distinctive ‘mosaic’ pattern of discolouration on the leaves which affects the growth of the plant due to lack of photosynthesis.

18
Q

What is Measles?

What does it do?

How does it spread?

How can its spreads be prevented?

A

Virus

Symptoms: Fever and a red skin rash - can be fatal if complications arise.

Prevention: Young children are vaccinated against measles.

Spread: Inhalation of droplets from sneezes and coughs.

19
Q

What is HIV? What are its symptoms? How does it spread?

A

Virus, Human Immunodeficiency Virus

Symptoms: HIV initially causes a flu-like illness. Unless successfully controlled with antiretroviral drugs the virus attacks the body’s immune cells. Late stage HIV infection, or AIDS, occurs when the body’s immune system becomes so badly damaged it can no longer deal with other infections or cancers.

Spread: Exchange of body fluids such as via sexual contact or when drug users share needles.

20
Q

What is Salmonella? How is it spread? How can it spread be prevented? What are its symptoms?

A

Bacteria

Spread: Food poisoning is spread by bacteria ingested in food, or on food prepared in unhygienic conditions.

Prevention: In the UK, poultry are vaccinated against Salmonella to control the spread.

Symptoms: Fever, abdominal cramps, vomiting and diarrhoea

21
Q

What is Gonorrhoea? What are its symptoms? How does it spread? How can its spread be prevented?

A

Bacterial

Spread: Sexually transmitted disease (STD)

Symptoms: Thick yellow or green discharge from the vagina or penis and pain on urinating.

Treatment: Antibiotic penicillin until many resistant strains appeared.

Prevention: Treatment with antibiotics or the use of a barrier method of contraception such as a condom.

22
Q

What is Rose black spot? What are its symptoms? How does it spread? How can its spread be prevented?

A

Fungus

Symptoms: Purple or black spots develop on leaves, which often turn yellow and drop early. It affects the growth of the plant as photosynthesis is reduced.

Spread: Water or wind.

Treatment: Fungicides and/or removing and destroying the affected leaves.

23
Q

What is Malaria? What are its symptoms? How does it spread? How can its spread be prevented?

A

The malarial protist has a life cycle that includes the mosquito.

Symptoms: Malaria causes recurrent episodes of fever and can be fatal.

Prevention: The spread of malaria is controlled by preventing the vectors, mosquitos, from breeding and by using mosquito nets to avoid being bitten.

24
Q

What are the non-specific defence systems the human body has to pathogen from entering the body?

A
  • Skin
    • Acts as a barrier
  • Mucus and cilia in the trachea and bronchi
    • Mucus is sticky and traps pathogens
    • Cilia wafts the mucus up the airways to the back of the throat, where the mucus is either swallowed or coughed out
  • Stomach has hydrochloric acid
    • Destroys pathogens
  • Nose hairs in the nose
    • Prevent the entry of pathogens
25
Q

How does the immune system try to destroy pathogens if they enter the body?

A
  • Phagocytes engulf and digest the pathogens
  • Lymphocytes produce antibodies which bind to the antigens on pathogens, which helps their destruction
  • Lymphocytes also produce antitoxins which neutralise toxins produced by bacteria
26
Q

How do vaccines provide immunity?

A

They inject a dead or weak, inactive form of the pathogen.

This stimulates an immune response, and so lymphocytes produce antibodies to attack the pathogen.

Memory lymphocytes are also produced.

If in the future that person is exposed to that same pathogen, their memory lymphocytes can make the antibodies…

  • sooner
  • faster
  • in bigger amount

… killing the pathogen before it has time to make the person ill.

27
Q

What are antibiotics used for?

A

To kill bacteria inside the body.

Specific bacteria need specific antibiotics.

28
Q

Why is it difficult to produce a drug that kills viruses?

A

Viruses live inside host (human) cells. A drug that kills a virus would have to kill the host’s own cell. It is difficult to develop drugs that kill viruses without also damaging the body’s tissues.

29
Q

Describe the use of painkillers.

A

Painkillers and other medicines are used to treat the symptoms of disease but do not kill pathogens.

Lolo (9 decks)

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