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Biology > Chapter 1 - Key Biology Concepts > Flashcards

Chapter 1 - Key Biology Concepts Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Name the two categories of cells

A

Eukaryotes and Prokaryotes

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2
Q

What are all living things made from?

A

Cells

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3
Q

Describe eukaryotic cells

A

Large, membrane bound organelle, nucleus, have histones

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4
Q

Describe prokaryotic cells

A

Small, no membrane bound organelle, nucleotide/chromosomes, have no histones

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5
Q

What are eukaryotes? Prokaryotes?

A

Eukaryotes are organisms made from eukaryotic cells. Prokaryotes are made from a prokaryotic cell - they are single-celled.

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6
Q

What is the name for the different parts of a cell?

A

Sub-cellular structures

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7
Q

Which sub-cellular structures do most animal cells have?

A

Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes

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8
Q

What is a nucleus?

A

Contains genetic material that controls the activities of the cell. The genetic material is arranged into chromosomes.

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9
Q

What is cytoplasm?

A

A gel-like substance where most of the chemical reactions happen in the cell. It contains enzymes that control chemical reactions

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10
Q

What is a cell membrane?

A

Holds the cell together and controls what goes in and out

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11
Q

What are mitochondria?

A

These are where most of the reactions for respiration take place. Respiration transfers the energy the cells need to work.

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12
Q

What are ribosomes?

A

These are involved in translation of genetic material - protein synthesis

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13
Q

What sub-cellular structures do most plant cells have?

A

Cell wall, large vacuole, choloplasts, and all the things an animal cell has (nucleus, cytoplasm, cell membrane, mitochondria, ribosomes)

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14
Q

What is a cell wall?

A

A rigid structure made from cellulose. It supports and strengthens the cell

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15
Q

What is a vacuole?

A

Contains cell sap - a weak solution of sugar and salts. It maintains the internal pressure to support the cell.

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16
Q

What are chloroplasts?

A

Where photosynthesis occurs - making food for the plant. They contain chlorophyll.

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17
Q

Do bacterial cells have a nucleus?

A

No

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18
Q

Which sub-cellular structures do bacterial cells have?

A

Chromosomal DNA, plasmid DNA, ribosomes, cell membrane, flagellum.

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19
Q

What is chromosomal DNA (in bacteria)?

A

ONE long circular chromosome which controls the cells activities and replication. It floats free in the cytoplasm and not a nucleus.

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20
Q

What is plasmid DNA?

A

Small loops of extra DNA that aren’t part of the chromosome. Plasmids contain genes for things like drug resistance.

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21
Q

What is a flagellum?

A

A long hair-like structure that rotates to make the bacterium move. It can be used to move the bacteria away from harmful substances like toxins and towards beneficial things like nutrients or oxygen.

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22
Q

Define specialised cells

A

Cells which have a structure which makes them adapted to their function

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23
Q

What is the formula for total magnification?

A

Total Magnification = eyepiece lens magnification X objective lens magnification

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24
Q

What is the formula for magnification?

A

Magnification = image size/real size

Note: Image size and real size must both be in the same units.

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25
Q

What is the name given to the molecule which is changed during a reaction with enzymes?

A

The substrate

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26
Q

What is the part of an enzyme where it joins on to its substrate to catalyze the reaction?

A

The active site

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27
Q

What happens if the substrate doesn’t fit into the active site shape? Does this have a name?

A

The reaction won’t be catalyzed. It’s called the ‘Lock and Key’ mechanism because the enzyme has high specificity for the the substrate and usually only works with one.

28
Q

What might affect the rate of reaction in enzymes?

A

Temperature, pH and substrate concentration.

29
Q

Why do enzymes have an optimum temperature (what happens if you heat them up)?

A

A higher temperature increases the rate at first. If it gets too hot, some of the hydrogen bonds holding the enzymes together break and change the shape of the active site - it is denatured.

30
Q

What happens if an enzyme is not at the optimum pH?

A

If it is too high or low, the hydrogen bonds in the enzyme will break and change the shape of the active site - it will be denatured.

31
Q

Explain the effect of substrate concentration on the rate of an enzyme-controlled reaction.

A

the higher the substrate concentration, the faster the rate of enzyme-controlled reaction up until the saturation point when all the active sites are filled up

32
Q

What is the formula for rate of reaction? What if the experiment measures how much something has changed?

A

Rate = 1000/time
Note: you can also use 1/time but 1000 gives a bigger number which is easier to plot on a graph.
Rate = Amount of change/time

33
Q

What are the three main digestion enzymes and what are they for?

A

Carbohydrases - Breaking down carbohydrates into simple sugars e.g. amylase breaks down starch
Proteases - Break down proteins to amino acids
Lipases - Convert lipids (fats and oils) into glycerol and fatty acids

34
Q

What is the name for when enzymes ‘rebuild’ molecules? What is an enzyme substrate complex?

A

Synthesis - they synthasise carbohydrates, proteins and lipids etc.
When two molecules join together due to an enzyme

35
Q

Which chemical can you use to test for sugars? How do you know if sugar is present?

A

Benedict’s Reagent (it’s blue).
Add it to a sample and heat the solution. If it tests positive, it will form a colored precipitate. The higher the concentration of sugar, the further along the colour changing chart it goes:
Blue-green-yellow-orange-brick red

36
Q

Which chemical can you use to test for starch? How do you know if starch is present?

A

Iodine.

Add iodine to the sample. If starch is present, the solution changes from browny-orange to a dark, blue-black colour.

37
Q

Which chemical test can you use to test for lipids? How do you know if lipids are present?

A

The Emulsion Test.
Shake the test substance with ethanol for around a minute until it dissolves then pour the solution into water. If lipids are present, They will precipitate out of the solution and form a milky solution. The more there are, the more noticeable the colour will be.

38
Q

Which chemical test can you use to test for proteins? How do you know if proteins are present?

A

Biuret Test
Add a few drops of potassium hydroxide to the solution to make it alkaline then add some copper sulfate solution (bright blue). If there is no protein, the solution will stay blue. If there is, it will turn purple.

39
Q

What is calorimetry? How do you do this?

A

‘Burning’ food to see how much energy it contains
Weigh a small amount of food (dry so that it burns) and skewer it on a mounted needle
Add a set volume of water to a boiling tube
Measure the temperature of the water then set fire to the food using a Bunsen Burner flame making sure the Bunsen isn’t near the water.
Immediately hold the food under the water until it goes out.
Then relight the food and repeat until it no longer catches fire.
Measure the temperature of the water again and use the energy in food formula to work out the amount of energy in the food.

40
Q

What is the formula for energy in food (Joules)?

How do you work out how many joules there are in each gram of flowers?

A

Energy in food (J) = mass of water in food (g) X Temperature change of water (degrees C) X 4.2

Energy per gram of food (J/g) = Energy in food (J) / mass of food (g)

41
Q

What is diffusion?

A

The net (overall) movement of particles from an area of high concentration to an area of lower concentration. It happens in liquids and gases because the particles in these substances are free to move about randomly.

42
Q

Which molecules diffuse through cell membranes?

A

Only very small molecules - things like glucose, amino acids, water and oxygen. Big molecules like starch and proteins can’t fit through.

43
Q

What is osmosis? What does this mean?

A

The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
A partially permeable membrane is one with very small holes in so only small molecules can fit through.
The water molecules go from a low solute concentration to a higher solute concentration as if it’s trying to ‘even up’ the solute concentration either side of the membrane.

44
Q

What is active transport?

A

The net movement of particles across a membrane AGAINST a concentration gradient (low to high) using energy transferred during respiration.

45
Q

What is the difference between diffusion + osmosis and active transport?

A

In active transport, particles move up the concentration gradient rather than down and the process requires energy

46
Q

Give an example of active transport in the digestive system

A

When there’s higher concentration of nutrients in the gut than in the blood the nutrients diffuse naturally into the blood but sometimes there’s a lower concentration of nutrients in the gut than in the blood. Active transport allows nutrients to be taken into the blood despite the fact that the concentration gradient is the wrong way. This is essential to stop us starving.

47
Q

What is an enzyme substrate complex?

A

When two molecules join together due to an enzyme. It rebuilds molecules

48
Q

Name some specialised cells

A

Root hair cell, red blood cell, sperm cell, pollen cell, palisade / plant cell, ciliates epithelial cells, nerve cells, egg / ovum cells

49
Q

What are enzymes? What do they do?

A

Enzymes are catalyst, they catalyse molecules therefore speeding up chemical reactions without changing themselves. They can have specific functions. Almost all metabolic processes in the cell need enzyme catalysis

50
Q

What enzyme cuts DNA strands in order for genetic engineering to happen?

A

Restriction enzyme or restriction endonuclease

51
Q

What does the action of scissor cutting enzyme models show?

A

The action of cutting enzymes on a large molecule as it quickly separates it into smaller molecules

52
Q

What does a protein molecule break down into? This is called what? What is the opposite of this process?

A

Amino acids, digestion

Amino acids form proteins by protein synthesis

53
Q

What do starch molecules break down into?

A

Glucose molecules

54
Q

What does fat/ lipid molecules break down into?

A

Glycerol and fatty acids

55
Q

What makes up an enzyme?

A

Protein twisted into a globular shape with a specific active site

56
Q

Give the main 2 processes that enzymes catalyse

A

Digestion and respiration

57
Q

What does the enzyme amylase do?

A

It’s found in saliva and small intestine, it breaks down starch into small sugars such as maltose

58
Q

What does the enzyme catalase do?

A

It is found in most cells but especially liver cells, it breaks down hydrogen peroxide made in many cell reactions to water and oxygen

59
Q

What is a phospholipid ?

A

A lipid containing a phosphate group in its molecule, it has 2 fatty lipid tails and a phosphate head

60
Q

What is does the enzyme starch synthase do?

A

It happens in a plant, synthesis of starch to glucose

61
Q

What does the enzyme DNA polymerase do?

A

Found in the nucleus, it does the synthesis of its DNA from its monomers

62
Q

Give the 4 main units that are smaller than a cm and decrease by x 1000 each time?

A 
Milli metres
/1000
Micrometres
/1000
Nanometers 
/1000
Picometres 
E.g. 150 micrometres, is 0.15 mm or 0.00015 m
63
Q

What are the 2 types of microscopes?

A

Electron and light

64
Q

What is the difference in resolution between a light and electron microscope?

A

Light is only 0.014 mm

Electron is 0.0000002 mm which is a much better resolution

65
Q

What happens to enzymes when the temperature gets to high?

A

The active sight of enzymes denature, meaning less substrate complexes are formed and less molecules are catalysed

Biology (7 decks)

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