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Genes and Health Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

How is air drawn to the lungs?

A

Air travels down the trachea due to low pressure in the lungs

created by increase in volume of thorax
as ribs move up
and as diaphragm moves down

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2
Q

What happens when the diaphragm muscles and those between the ribs relax?

A

Volume of thorax decreases

pressure rises

air is forced out through the trachea

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3
Q

Describe the structure of the trachea.

A

It’s divided into two bronchi which carry air to and from lungs

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4
Q

Describe the structure of the lungs.

A

Tree-like system of tubes

Ending in narrow tubes, bronchioles

These are attached to tiny balloon-like alveoli

sites of gas exchange

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5
Q

Where is mucus produced?

A

Produced continuously from goblet cells in the walls of the airways

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6
Q

How is mucus removed?

A

Continuously removed by the wave-like beating of cilia that cover epithelial cells lining the tubes of the gas exchange system

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7
Q

How does sticky mucus effect our health?

A

Increases chance of lung infection

Makes gas exchange less efficient

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8
Q

Where can epithelial cells be found?

A

On the outer surface of many animals including mammals

Line cavities and tubes within animals

Cover surfaces of internal organs

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9
Q

Name the surfaces of the epithelium.

A

Surface that faces the basement membrane - basal membrane

Surface that faces away - apical membrane

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10
Q

What are microorganisms that cause illness called?

A

Pathogens

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11
Q

How are pathogens killed?

A

Pathogens get trapped in mucus which is moved by the cilia into back of the mouth cavity

Either coughed out or swallowed, reducing risk of infection

If swallowed the stomach acid kills most microorganisms

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12
Q

What effect does CF have on the mucus?

A

Mucus is sticky so can’t move

Production still continues
layers of thickened mucus build up

Low levels of oxygen in mucus due to oxygen diffusing slowly or epithelial cells use up more oxygen in CF patients

harmful bacteria can thrive in anaerobic conditions

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13
Q

How do white blood cells make mucus even stickier?

A

White blood cells fight infections within mucus but as they die they break down and release DNA that makes mucus even more sticky

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14
Q

How does oxygen cross the walls of the alveoli into the blood?

A

Diffusion

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15
Q

What’s special about the surface membrane’s in unicellular organisms?

A

All of the surface area is the exchange surface.

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16
Q

How is a concentration gradient maintained?

A

Cells continuously using the substances absorbed and producing waste

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17
Q

What are the main features of a gas exchange surface?

A

Large surface area of alveoli

Numerous capillaries around the alveoli

Thin walls of alveoli and capillaries

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18
Q

What three properties is the rate of diffusion dependant on?

A

Surface area –> directly proportional

Concentration gradient –> directly proportional to the difference in concentration across the gas exchange surface

Thickness of gas exchange surface –> inversely proportional

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19
Q

Why is there less water in mucus with people with CF?

A

Due to abnormal salt and water transportation across cell surface membranes

Caused by a faulty transport protein channel in membrane

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20
Q

What is a peptide bond?

A

A bond that forms between -COOH + -NH2 of 2 amino acids when they join in a condensation reaction to form a dipeptide

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21
Q

What is the primary structure of a protein?

A

The sequence of amino acids in the polypeptide chain

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22
Q

What is the secondary structure of a protein?

A

Interactions between the amino acids in the polypeptide chain cause the chain to change shape into either α-helices or β-pleated sheets

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23
Q

Describe a α-helix

A

extended spring

hydrogen bonds form between the slightly negative C=O of the carboxylic acid and the slightly positive -NH of the amine group of different amino acids

stabilises the shape

sections of α-helix can be up to 35 amino acids long

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24
Q

Describe β-pleated sheets

A

amino acid chains fold back on themselves

about 15 amino acids in length

may link together with hydrogen bonds holding parallel chains in arrangement

Hydrogen bonds are weak but overall the H-bonds make the structure quite stable

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25
Q

What is the tertiary structure of a protein?

A

Polypeptide chains often bend and folds further to produce a precise 3D shape

chemical bonds and hydrophobic interactions between R groups maintain the tertiary structure

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26
Q

What makes an R group polar?

A

When the sharing of electrons within it isn’t even

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27
Q

What makes R groups hydrophilic?

A

As they are polar they attract other polar molecules such as water.

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28
Q

What makes an R group hydrophobic?

A

If it isn’t polar

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29
Q

How does a covalent disulphide bond form?

A

If two cysteine R groups are close to each other, a covalent disulphide bond will form as they contain a -SH side group.

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30
Q

What’s the strongest type of bond?

A

Disulphide and ionic bonds are stronger than hydrogen bonds.

However they are sensitive to changes in pH

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31
Q

What is a quaternary structure?

A

Proteins that have more than one polypeptide chains.

Single chain proteins stop at the tertiary level.

32
Q

What is a conjugated protein?

A

Proteins that have another chemical group associated with their polypeptide chain(s).

33
Q

What are the two distinct shapes of proteins?

A

Globular and Fibrous

34
Q

Describe a globular protein.

A

Polypeptide chain is folded into a compact spherical shape
.
Soluble due to hydrophilic side chains

important in metabolic reactions

3D shape is crucial to their roles in binding to other substances

Examples: enzymes

35
Q

Describe a fibrous protein.

A

Long chains

Several polypeptide chains can be linked for additional strength

Insoluble

Important structural molecules

Examples: Collagen

36
Q

What is the phospholipid bilayer?

A

The surface membrane of epithelial cells are made up of two layers of phospholipids

37
Q

Why is the phosphate head hydrophilic?

A

The phosphate head is polar

One end is slightly positive
The rest is slightly negative

38
Q

Why is the fatty acid tail hydrophobic?

A

It’s non-polar

39
Q

How do phospholipids arrange themselves in water?

A

Form a bilayer

Hydrophobic tails point inwards

Hydrophilic phosphate heads face inwards

Due to aqueous conditions on either side, bilayer forms

40
Q

What are glycoproteins and glycolipids?

A

Glycoproteins- protein molecules with polysaccharides attached.

Glycolipids - lipid molecules with polysaccharides attached.

41
Q

What makes the fluid mosaic model more fluid?

A

The greater the ratio of phospholipids that contain unsaturated fatty acids to those containing saturated fatty acids.

The kinks in the hydrocarbon tails prevent them form packing closely together

therefore more movement is possible

Cholesterol sits between the phospholipids and maintains fluidity of membrane

42
Q

What is the importance of glycolipids and glycoproteins?

A

Helps cell-to-cell recognition and as receptors

43
Q

How do molecules and ions move across membranes?

A

Diffusion

Osmosis

Active transport

Exocytosis

Endocytosis

44
Q

What is diffusion?

A

Net movement from an area of high concentration to an area of low concentration.

hydrophobic or small uncharged molecule pass
through phospholipid bilayer

passive, no energy required

45
Q

What is facilitated diffusion?

A

Polar molecules and ions cross membranes using carrier proteins or channel proteins.

passive, no energy required

46
Q

What is osmosis?

A

Net movement of water molecules from an area of low concentration to an area of high concentration through a partially permeable membrane.

through phospholipid bilayer

passive, no energy required

47
Q

What is active transport?

A

Against a concentration gradient, from low to high
conc. using energy supplied by ATP

requires energy supplied by ATP

48
Q

What is exocytosis?

A

Release of a substance using vesicles.

used for bulk transport of substances out of the cell

vesicles fuse with the cell surface membrane, releasing their contents

49
Q

What is endocytosis?

A

Taking in a molecule using vesicles.

used for bulk transport of substances into the cell

vesicles are created from the cell surface membrane, bringing their contents into the cell

50
Q

How are the lungs adapted for gas exchange?

A

Alveoli have a large surface area.

They are surrounded by a number of capillaries which leads to a short diffusion path due to the thinness of walls.

There is a steep concentration gradient between the alveoli and the blood.

51
Q

Describe Fick’s Law.

A

Increased surface area and a greater concentration gradient increase rate of diffusion.
Thicker surface areas reduce rate of diffusion.

Rate of diffusion is directly proportional to surface area x concentration difference divided by the thickness of the surface.

52
Q

Describe globular and fibrous proteins.

A

Globular proteins are compact and spherical. They are soluble.

Fibrous proteins are long chains that are strong and cross-linked. They are insoluble.

53
Q

Describe the phospholipid bilayer.

A

Phosphate heads are polar and hydrophilic. Fatty acid tails are non-polar and hydrophobic.

54
Q

Describe what happens where there is extra water in the mucus.

A

Sodium is transported across the basal membrane and diffuses through sodium channels.

Chlorine diffuses down an electrical gradient.

Water is drawn out of cells due to the high salt concentration and then drawn out of the mucus.

55
Q

Describe what happens hen there is too little water in the mucus.

A

Chlorine is transported across the basal membrane and diffuses through an open CFTR channel.

Sodium diffuses down an electrical gradient.

Water is drawn out of the cell and into the mucus.

56
Q

Describe what happens in cystic fibrosis sufferers.

A

CFTR channel is absent or dysfunctional.

Sodium channel is permanently open.

Water is constantly being removed.

57
Q

Describe the effect of cystic fibrosis on the digestive system.

A

ancreatic duct blocked with mucus, prevents release of digestive enzymes,

food is not digested properly, resulting in malabsorption syndrome.

58
Q

Describe the effect of cystic fibrosis on the reproductive system.

A

Females are less likely to become pregnant due to a mucus plug in the cervix.

Males may have a mucus plug in the cast deferens or may lack the vas deferens.

59
Q

What is the formula for calculating BMI.

A

Weight (kg) divided by height^2 (m^2) .

60
Q

Describe DNA.

A

Made up of a phosphate, deoxyribose sugar and a nitrogenous base of adenine, thymine, guanine or cytosine.

This is a nucleotide, with phosphodiester bonds, formed by a condensation reaction.

61
Q

Describe RNA.

A

Made up of a phosphate, a ribose sugar and a nitrogenous base of adenine, uracil, guanine and cytosine.

62
Q

Describe transcription.

A

DNA helicase unzips hydrogen bonds in the double helix.

RNA polymerase base pairs free complementary RNA nucleotides, forming the coding strand, which produces a single strand of RNA.

63
Q

Describe translation.

A

mRNA leaves the nucleus to the ribosomes.

Triplets of based form codons which are matched with complementary anticodons on tRNA.

Amino acids attached to tRNA forms peptide bonds and primary structure.

Translation is caused by a start and a stop codon.

The code is non overlapping and degenerate.

64
Q

What are the different types of mutations?

A

Substitution, insertion, deletion, frame shift.

65
Q

Describe Stahl and Meselson’s experiment.

A

DNA is grown in heavy Nitrogen (15).

Moved to 14N.

New nucleotides were light, original were heavy.

Divided and replicated once.

66
Q

Define molecular phylogeny.

A

Tests DNA to look for similarities in order to determine sequences

67
Q

Describe amniocentesis.

A

15-17 weeks.

Inserts a needle into amniotic fluid.

1% risk of miscarriage.

68
Q

Describe chorionic villus sampling.

A

8-12 weeks.

Removal of placental tissue through the abdomen or vagina.

1-2% risk of a miscarriage.

69
Q

Describe non-invasive prenatal diagnosis.

A

7-9 weeks.

Analyses blood plasma.

70
Q

Describe pre-implantation genetic diagnosis.

A

IVF created embryos of which cells are tested.

71
Q

Describe gene therapy.

A

Desired gene inserted into a vector. Modified DNA put into a human cell. Produces a functional protein.

72
Q

Define intracellular reactions.

A

Enzyme reactions that occur inside cells.

73
Q

Define extracellular reactions.

A

Enzyme reactions that occur outside of the cell.

74
Q

Define gene.

A

A sequence of bases that codes for a polypeptide chain

75
Q

Define allele.

A

different version of a gene

76
Q

Define monohybrid inheritance.

A

A characteristic is only controlled by one gene.

Biology (5 decks)

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