Chapter 7: Units of life Flashcards

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1
Q

What is a cell?

A

The basic units for all living organisms

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2
Q

What is cell theory?

A

It states that:
- Cells are the smallest, living organisational unit
- All organisms are formed by cells
- All cells come from pre-existing cells

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3
Q

What is the cell membrane?

A

It is a layer of phospholipid that encloses the cytoplasm. It allows things to the transported in and out of a cell while keeping it separate from other cells.

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4
Q

What is cytoplasm?

A

A jelly-like substance that fills the space between organelles.

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5
Q

What is cytosol?

A

It is the fluid component to cytoplasm.

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6
Q

What is DNA?

A

It contains genetic and hereditary information. It also directs activities.

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7
Q

What are flagella?

A

It is whip-like and can act as a propeller to move the cell.

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8
Q

What are cilia?

A

These are small and hair-like and act like oars to move the cell.

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9
Q

What are the two main types of cells?

A

Prokaryotes
Eukaryotes

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10
Q

What are prokaryotes?

A

These are small and have one cell
Scattered ribosomes
Not bound to membrane wall
Have a cell wall made of protein
The cell performs all functions itself without specialisations.

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11
Q

What are eukaryotes?

A

These have DNA in the nucleus in the form of chromosomes
They have organelles

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12
Q

What are the main differences between prokaryotes and eukaryotes?

A

Prokaryotes are single-celled
Prokaryotes are not bound to a membrane wall
Eukaryotes have organelles

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13
Q

What is solely inside a plant cell?

A

Cell wall made of cellulose
Large vacuole
Plastids

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14
Q

What is solely inside an animal cell?

A

Centriole

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15
Q

What is the cell wall?

A

These are only found in plant cells and are non-living cellulose structures outside the cell membrane. It provides support.

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16
Q

What is lignin?

A

Provides support for woody plants

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17
Q

What is a centriole?

A

Small, cylinder structures that are composed of microtubules and separate chromosomes during cell division.

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18
Q

What is the smooth endoplasmic reticulum?

A

It is a network of membranes that link the organelles in a cell. It does not have ribosomes.

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19
Q

What is the rough endoplasmic reticulum?

A

It is a network of membranes that link the organelles in a cell. It has ribosomes.

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20
Q

What is the golgi apparatus?

A

It is responsible for the packaging, distribution and transport of proteins.

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21
Q

What are the lysosomes?

A

They are found in animal cells and have enzymes that break down foreign material and debris. It can also break down its own cell.

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22
Q

What are the mitochondria?

A

They are the powerhouse of the cell. They transform energy to be used by the cell.

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23
Q

What is the nucleus?

A

A large organelle that has the DNA for the cell.

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24
Q

What is the nuclear membrane?

A

It surrounds the nucleus and has pores to allow the nucleus to communicate with other organelles.

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25
Q

What are ribosomes?

A

Sites where proteins are packaged.

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26
Q

What are vacuoles?

A

These are membrane-bound and contain food, enzymes and fluid.

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27
Q

What are vesicles?

A

These transport substances within the cell.

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28
Q

What is a contractile vacuole?

A

These are found in protists and pump out excess water.

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29
Q

What is a food vacuole?

A

These are formed by cellular eating and are a part of amoebas.

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30
Q

What is phagocytosis?

A

Cellular eating

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31
Q

What is pinocytosis?

A

Cellular drinking

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32
Q

What is endocytosis?

A

Brining in

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33
Q

What is exocytosis?

A

Expelling out

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34
Q

What does the development of the cell include?

A

Cell division
Cell growth
Cell differentiation

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35
Q

What is cell differentiation?

A

This is where cells take on specialised functions to perform different roles within an organism.

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36
Q

What happens to the DNA not used during cell differentiation?

A

It is simply “switched off” and not used. The cell still retains the genetic code for all types of cells.

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37
Q

What do all cells begin as?

A

Stem cells

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38
Q

What is the cellular environment?

A

This is where unicellular organisms live

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39
Q

What is a protist’s cellular environment?

A

Protist’s can only move from one environment to the next
They either tolerate the conditions for die

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40
Q

What is the extracellular environment?

A

This is the area outside an individual cell in a complex organism

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41
Q

What must a cell in a complex organism do to survive?

A

They must exchange carbon dioxide, oxygen, nutrients from food and waste removal.

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42
Q

What must a cell do to function efficiently?

A

They must control salt, temperature, waste and pH.

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43
Q

What are phagocytic cells?

A

These remove dead cells

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44
Q

How can cells die

A

Conditions become unbearable
Commit suicide

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45
Q

What is cell suicide also known as?

A

This is known as physiological or programmed cell death.

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46
Q

What are all things made up of?

A

Hydrogen, carbon, calcium and nitrogen

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47
Q

What are the 2 types of compounds?

A

Inorganic and organic

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48
Q

What are the 4 types of INORGANIC compounds?

A

Water
Oxygen
Carbon Dioxide
Minerals

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49
Q

What properties make water useful in chemical reactions?

A

Cohesion
Adhesion
High Heat Capacity

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50
Q

What is adhesion?

A

The water molecule can stick to other molecules.

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51
Q

What is cohesion?

A

The water molecule can stick to itself.

52
Q

What is High Heat Capacity in regard to water?

A

It is the ability for a water molecule to absorb a lot of heat without an increase in temperature.

53
Q

Why is oxygen important to cells?

A

This is needed to release energy from food.

54
Q

What are minerals?

A

These are dissolved within the cytosol of the cell.
They are included in the structure of cells, enzymes and vitamins.

55
Q

What are the 4 main types of ORGANIC compounds?

A

Carbohydrates
Lipids
Proteins
Nucleic Acids

56
Q

What are the main components of carbohydrates?

A

Carbon
Hydrogen
Oxygen

57
Q

What are carbohydrates?

A

These are the main source of chemical energy for organisms.

58
Q

What is the basic sub-unit of carbohydrates?

A

Monosaccharides
e.g Glucose

59
Q

What is a disaccharide?

A

Two simple sugars joined together.
e.g Sucrose

60
Q

What are polysaccharides?

A

Multiple simple sugars bound together into longer chains

61
Q

What are lipids?

A

These are:
Fats
Oils
Phospholipids
Steriods

62
Q

What are proteins?

A

These are used for structural support, storage, transport, signalling, movement and defence.

63
Q

What do proteins do as enzymes?

A

They regulate metabolism

64
Q

How does a protein’s specific shape help it to do its job?

A

It relies on its ability to recognise and bind to other molecules

65
Q

When is a protein denatured?

A

If the pH, salt, temperature, etc. are altered

66
Q

What happens when a protein becomes denatured?

A

It unravels and loses its abilityy to perform its job

67
Q

What is cellular respiration?

A

The process of extracting energy from glucose molecules

68
Q

What is starch?

A

It is a storage polysaccharide in plants

69
Q

Where is starch stored?

A

It is in plastids including chloroplasts

70
Q

What is glycogen?

A

It is a storage polysaccharide in animals

71
Q

Where is glycogen stored?

A

In the liver and muscle cells

72
Q

What is chitin?

A

Used by arthropods to build their exoskeletons
Used by fungi to build their cell walls

73
Q

What organic compound is hydrophobic?

A

Lipids

74
Q

What is fat constructed of?

A

Glycerol
Fatty Acid

75
Q

What is triglyceride?

A

Three fatty acids are joined to glycerol

76
Q

What is unsaturated fat?

A

It has one or more double bonds

77
Q

What is saturated fat?

A

There is no double bonds whatsoever

78
Q

What fats solidify at room temperature?

A

Most animal fats that are saturated

79
Q

What fats liquefy at room temperature?

A

Most fats that are fish or plant-based are unsaturated

80
Q

What are oils?

A

Plant and fish fats

81
Q

What is the major function of fats?

A

Energy storage

82
Q

What are adipose cells?

A

These shrink and expand as fat is deposited and withdrawn

83
Q

What are amino acids?

A

These are the building blocks of protein

84
Q

What are amino acids linked by?

A

Peptide bond

85
Q

What are nucleic acids?

A

These are the genetic material for all organisms

86
Q

What are the 2 types of nucleic acids?

A

Deoxyribonucleic Acid (DNA)
Ribonucleic Acid (RNA)

87
Q

What are nucleotides?

A

These are what make up nucleic acids

88
Q

What happens to cells as they get larger but stay the same shape?

A

They have a smaller surface area in which they can exchange materials

89
Q

Why do cells and organisms change shape when they get bigger?

A

So they have increased surface area

90
Q

What particles does a cell membrane allow through?

A

Solutions and some solid food particles

91
Q

What does partially permeable mean?

A

Only some substances will be able to pass through it

92
Q

How can a cell take in and expel substances?

A

Diffusion and active transport

93
Q

What are cell membranes composed of?

A

A phospholipid bilayer
Glycolipids
Glycoproteins
Cholesterol

94
Q

What are the two molecules in the phospholipid bilayer?

A

A hydrophobic tail
A hydrophilic head

95
Q

What happens when the phospholipid bilayer comes into contact with an aqueous solution?

A

The hydrophilic heads point toward the solution
It also makes the membrane impermeable

96
Q

What are the other 3 parts of the cell membrane?

A

Glycolipids
Glycoproteins
Cholesterol

97
Q

What do glycolipids do in the cell membrane?

A

Stabilise the cell membrane

98
Q

What do glycoproteins do in the cell membrane?

A

Cellular recognition and immune response

99
Q

What does cholesterol do in the cell membrane?

A

Regulates fluidity in the cell membrane

100
Q

What is diffusion?

A

The net movement of molecules from an area of high concentration to low concentration

101
Q

Does diffusion require energy?

A

No, it is a passive process

102
Q

What is the concentration gradient?

A

It is the difference between the exterior and interior of the cell

103
Q

What is osmosis?

A

It is diffusion that exclusively applies to water molecules

104
Q

What happens when the cell membrane separates dilute solutions from concentrated solutions?

A

There is a net movement from dilute to concentrated

105
Q

Does osmosis require energy?

A

No, it is a passive process

106
Q

What is equilibrium?

A

Where molecules moves in and out of a cell at a constant rate

107
Q

What is facilitated diffusion?

A

The use of proteins to carry ions across a cell membrane

108
Q

Does facilitated diffusion require energy?

A

No, it is a passive process

109
Q

What is active transport?

A

This transports molecules against the concentration gradient

110
Q

Does active transport require energy?

A

Yes, it requires energy in the form of ATP

111
Q

What is a hypotonic solution?

A

This is a lower concentration of solutes

112
Q

What is an isotonic solution?

A

Same concentration of solutes

113
Q

What is a hypertonic solution?

A

This is a higher concentration of solutes

114
Q

What effect does a hypertonic solution have on animal cells?

A

Shrivels as water leaves the cell

115
Q

What effect does a hypertonic solution have on plant cells?

A

Cell becomes plasmolyzed
Cell wall and cell membrane detach and deform the cell

116
Q

What effect does an isotonic solution have on animal cells?

A

Normal cell

117
Q

What effect does an isotonic solution have on a plant cell?

A

Cell is flaccid
Not enough water to keep the vacuole full

118
Q

What effect does a hypotonic solution have on an animal cell?

A

Cell becomes lysed
Cell bursts as it cannot remove water fast enough

119
Q

What effect does a hypotonic solution have on a plant cell?

A

Cell becomes turgid
Normal state

120
Q

What is homeostasis?

A

The conditions of a stable internal environment for the cells to live in

121
Q

What happens when the internal environment is not meeting homeostasis?

A

Cells act to correct the change

122
Q

What factors affect homeostasis?

A

Infection
Trauma
Toxic substances
Auto-immune diseases
Inherited disorders

123
Q

What is the receptor?

A

It detects change in the cellular environment

124
Q

What is the control centre?

A

This processes the information given by the receptor

125
Q

What is the effector?

A

Directs the appropriate response

126
Q

What are feedback loops?

A

This is what happens when a stressor is introduced into the environment, and the body takes steps to maintain homeostasis.