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CELS 191 > Cell Structure and Diversity > Flashcards

Cell Structure and Diversity Flashcards

1
Q

What are the 8 characteristics that define life?

A
  1. cellular organisation
  2. reproduction
  3. metabolism
  4. homeostasis
  5. heredity
  6. response to stimuli
  7. growth and development
  8. adaption through evolution
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2
Q

What is the size range of a eukaryote cell?

A

10 - 100 μm

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3
Q

1mm = ? μm

A

1000

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4
Q

1μm = ? nm

A

1000

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5
Q

What is the size range of a prokaryote cell?

A

less than 5μm

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6
Q

About how big is the nucleus of a cell?

A

10 μm

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7
Q

About how big is the mitochondrion?

A

1μm

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8
Q

What is the size range of viruses?

A

10 - 100 nm

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9
Q

About how big are ribosomes?

A

25 nm

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10
Q

About how big are proteins?

A

1 - 10 nm

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11
Q

The components of a cell are measured in

A

nanometres (1/1000000 mm)

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12
Q

About how big are membranes?

A

7-8 nm

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13
Q

What was Darwin’s proposed mechanism for evolution?

A

Natural selection

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14
Q

What are four things that are required for natural selection?

A
  • Variation within a population
  • Inheritance (parents passing on traits genetically)
  • Selection (some variants produce more than others)
  • Time (many generations)
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15
Q

Outline the purpose of a phylogenetic tree

A
  • represent a hypothesis about evolutionary relationships
  • these relationships are depicted as two-way branch points
  • each branch point represents the common ancestor of the two evolutionary lineages diverging from it
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16
Q

What are the three domains that define the origin of life?

A

Eukarya
Archaea
Bacteria

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17
Q

Describe the process of endosymbiosis

A

Organelles such as chloroplasts and mitochondria that are present in Eukaryote cells derived from bacteria.
The bacteria were engulfed by the ancestors of eukaryotes and were tamed

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18
Q

What are the 8 ranks of living things?

A 
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
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19
Q

The domain Archaea has what sort of cells

A

Prokaryotic cells

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20
Q

The domain Bacteria has what sort of cells

A

Prokaryotic cells

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21
Q

The domain Eukarya has what sort of cells

A

Eukaryotic cells

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22
Q

What are the 4 kingdoms that come under the domain Eukarya

A

Animalia Kingdom
Plantae Kingdom
Fungi Kingdom
Protozoa Kingdom

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23
Q

What are some examples of organisms in the Protista Kingdom?

A

Slime moulds

Algae

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24
Q

Which of the domains contain a nuclear envelope?

A

Eukarya

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25
Q

Which of the domains contain membrane-bound organelles?

A

Eukarya

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26
Q

Which of the domains contain peptidoglycan in the cell walls?

A

Bacteria

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27
Q

Which of the domains have circular chromosomes?

A

Bacteria

Archaea

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28
Q

Which of the domains can grow at temperatures above 100°C

A

Some species of Archaea

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29
Q

What are some key differences between prokaryotic and eukaryotic cells?

A
  • Eukaryotic cells contain membrane bound organelles and prokaryotic cells do not
  • the DNA is in the nucleus of eukaryotic cells but in the nucleoid (non-membrane enclosed) in prokaryotic cells
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30
Q

What are some similarities between prokaryotic and eukaryotic cells?

A

Both have

  • plasma membrane
  • cytosol
  • chromosomes carrying genes in DNA
  • ribosomes making proteins
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31
Q

Building blocks/monomers join together to form

A

macromolecules

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32
Q

Macromolecules come together to make

A

supramolecular assemblies

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33
Q

Supramolecular assemblies come together to make

A

organelles

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34
Q

Amino acids (monomers) join together to form which macromolecule?

A

Proteins

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35
Q

Nucleotides (monomers) join together to form which macromolecule?

A

DNA

RNA

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36
Q

Simple carbohydrates (monosaccharides - monomers) join together to form which macromolecule?

A

Complex carbohydrates (polysaccharides)

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37
Q

Glycerol, fatty acids, hydrocarbon rings (building blocks) join together to form which macromolecule?

A

Lipids

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38
Q

Are lipids polymers

A

No

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39
Q

What are some examples of supramolecular assemblies?

A

membranes, ribosomes, chromatin

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40
Q

What are the four levels of carbohydrates?

A 
Monosaccharides (monomers)
Disaccharides
Oligosaccharides
Polysaccharides (polymer)
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41
Q

What are some examples of monosaccharides?

A 
Hexose monosaccharides including
- glucose
- fructose
- galactose
Pentose monosaccharides including
- ribose
- deoxyribose
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42
Q

What are some examples of disaccharides?

A
  • Sucrose (Glucose + Fructose)
  • Lactose (Glucose + Galactose)
  • Maltose (Fructose + Galactose)
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43
Q

What are some examples of polysaccharides?

A
  • Starch eg. amylopectin (plant carbohydrate)
  • Cellulose (fibre - plant carbohydrate)
  • Glycogen (animal carbohydrate)
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44
Q

Amylose is

A

A linear component of starch

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45
Q

What are the three functions of carbohydrates?

A
  • structure
  • recognition
  • energy
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46
Q

Give an example of how a carbohydrate helps with structure

A

Cellulose is in the plant wall which helps maintain the structure and shape of the cell

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47
Q

Give an example of how a carbohydrate helps with energy

A

Plants use starch for energy storage

Animals use glycogen for energy storage

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48
Q

Give an example of how a carbohydrate helps with recognition

A

carbohydrates on the cell membrane can recognise viruses and bacteria and alert the immune system

they also allow the cells to communicate with other cells

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49
Q

What are some examples of nucleic acids

A

DNA

RNA

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50
Q

Nucleic acids are made up of

A

Nucleotides

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51
Q

What three components make up a nucleotide

A

Phosphate group
Sugar (deoxyribose or ribose)
Base (A,C,T/U,G)

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52
Q

What are the differences between RNA and DNA?

A 
RNA:
- single stranded
- (-OH) group on the 2C of the ribose sugar
DNA
- double stranded
- (H) on the 2C of the deoxyribose sugar
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53
Q

Proteins are polymers of

A

amino acids

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54
Q

What two functional groups do every amino acid have?

A
  • NH2

- COOH

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55
Q

What is the function of a nucleic acid?

A

The storage and expression of genetic information.

They tell the cell what to do, when to do it, how much to do and when to stop doing it

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56
Q

What are some of the functions of proteins? (8)

A
  1. structural
  2. regulatory
  3. transport
  4. storage
  5. catalytic
  6. contractile
  7. protective
  8. toxic
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57
Q

Give an example of a structural protein

A

Collagen in skin and bones

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58
Q

Give an example of a regulatory protein

A

insulin (a peptide hormone)

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59
Q

Give an example of a transport protein

A

haemoglobin carrying oxygen

Cytochrome c carrying electrons

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60
Q

Give an example of a storage protein

A

albumen (egg white)

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61
Q

Give an example of a catalytic protein

A 
RNA polymerase (enzymes)
hydrolytic in lysosomes
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62
Q

Give an example of a contractile protein

A

actin and myosin in muscles

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63
Q

Give an example of a protective protein

A

antibodies

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64
Q

Give an example of a toxic protein

A

diphtheria toxin

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65
Q

Lipids are not

A

Polymers

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66
Q

All lipids are

A

hydrophobic

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67
Q

Give some examples of lipids (5)

A
  1. triaclglycerol (fats)
  2. steroids
  3. phospholipids
  4. glycolipids
  5. fat soluble vitamins
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68
Q

What are three functions of lipids?

A
  1. Structural
  2. regulatory
  3. energy
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69
Q

Give an example of how a lipid helps with structure

A

phospholipids which make up the plasma membrane and cholesterol which makes sure everything in the membrane is the right consistency

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70
Q

Give an example of how a lipid helps with regulation

A

Cholesterol is a regulatory lipid regulating testosterone and oestrogen

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71
Q

Give an example of how a lipid helps with energy

A

Fats:

Glycerol backbone and 3 fatty acid chains

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72
Q

What must a cell do? (5)

A 
Manufacture cellular materials
Obtain raw materials
remove waste
Generate required energy
Control all of the above
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73
Q

What are 5 purposes of organelles?

A
  • provide special conditions for specific processes
  • keep incompatible processes apart
  • allow specific substances to be concentrated
  • form concentration gradients
  • package substances for transport or export
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74
Q

What are some organelles that both animal and plant cells have?

A
  • Endoplasmic reticulum
  • Nucleus
  • Mitochondrion
  • Golgi
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75
Q

What are some organelles that are only in animal cells?

A
  • lysosomes
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76
Q

What are some organelles that are only in plant cells?

A
  • central vacuole

- chloroplast

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77
Q

Which cells (plants, animals, protists) have a cell wall?

A

Plants: present
Animals: absent
Protists: may or may not be present

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78
Q

Which cells (plants, animals, protists) have a cytosol?

A

Plants: present
Animals: present
Protists: present

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79
Q

Which cells (plants, animals, protists) have a plasma membrane?

A

Plants: present
Animals: present
Protists: present

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80
Q

Which cells (plants, animals, protists) have a central vacuole?

A

Plants: present
Animals: absent
Protists: present

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81
Q

Which cells (plants, animals, protists) have a nucleus?

A

Plants: present
Animals: present
Protists: present

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82
Q

Which cells (plants, animals, protists) have a chloroplast?

A

Plants: present
Animals: absent
Protists: may or may not be present

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83
Q

Which cells (plants, animals, protists) have a lysosome?

A

Plants: absent
Animals: present
Protists: may or may not be present

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84
Q

Which cells (plants, animals, protists) have motility?

A

Plants: absent
Animals: present in some cells
Protists: may or may not be present

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85
Q

What are the sizes of plant cells, animal cells and protists?

A

Plants: 10 - 100 μm
Animals: 10 - 30 μm
Protists: less than 1 μm to metres

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86
Q

Which cells (plants, animals) have a centrosome?

A

Plants: absent
Animals: present

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87
Q

Which cells (plants, animals) have flagella?

A

Plants: absent
Animals: present in some cells

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88
Q

Which cells (plants, animals) have a mitochondria?

A

Plants: present
Animals: present

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89
Q

Which cells (plants, animals) have plasmodesmata?

A

Plants: present
Animals: absent

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90
Q

About the plasma membrane including its function

A

the phospholipid bilayer which encloses the cell
Function:
controls the movement of substances into and out of the cell

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91
Q

What are some organelles that have their own membrane

A
  • endoplasmic reticulum
  • lysosomes
  • mitochondria (two membranes)
  • nucleus (nuclear envelope)
  • chloroplast (two membranes)
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92
Q

Describe the phospholipid bilayer

A

made of phospholipids with a hydrophilic head and a hydrophobic tail
the hydrophilic heads shield the hydrophobic tails from the aqueous environment inside and outside of the cell

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93
Q

What is passive transport?

A

Transport of molecules across the plasma membrane which requires no energy

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94
Q

What are some examples of passive transport?

A
  • diffusion

- facilitated diffusion (including osmosis)

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95
Q

Explain the process of diffusion

A

lipid soluble (hydrophobic) molecules such as steroid hormones and gases move down their concentration gradient into the cell without the use of energy

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96
Q

Explain the process of facilitated diffusion

A

the movement of hydrophobic molecules such as glucose, ions and water down their concentration gradient into the cell through channels and carriers without the use of energy

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97
Q

Explain the process of osmosis

A

the movement of water from a low solute concentration to a high solute concentration through channels called aquaporins without the use of energy

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98
Q

Why is osmosis an example of facilitated diffusion

A

Because it is the movement of hydrophilic water across the hydrophobic membrane and therefore requires channels

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99
Q

What is active transport?

A

Movement of molecules across a membrane with the use of energy

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100
Q

What is required for active transport?

A

Transport proteins that require energy supplied by ATP

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101
Q

What is the purpose of active transport?

A

To move substances against their concentration gradient which allows the cell to have a different concentration of a substance that is different to its surroundings

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102
Q

What is co-transport?

A

an example of indirect active transport

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103
Q

Describe the process of co-transport:

A 
once substance (often H+) is pumped across the membrane via active transport (using energy)
the concentration gradient of H+ ions are used to drive a second substance (eg. sucrose) against its concentration gradient (no energy required)
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104
Q

What are 4 roles of membrane proteins

A
  1. signal transduction
  2. cell recognition
  3. intercellular joining
  4. linking the cytoskeleton to the extracellular matrix
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105
Q

What is signal transduction?

A

relaying messages from environment to the inside of the cell

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106
Q

What sort of messages would the environment send into the cell through signal transduction?

A 
grow
divide
move
make something
die
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107
Q

What is the significance of cell recognition?

A

the proteins allow the cells to interact close up

this involves glycoproteins

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108
Q

What are glycoproteins?

A

Proteins with added sugars

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109
Q

What is intercellular joining?

A

Proteins forming long lasting connections between the cells

110
Q

What is the significance of linking the cytoskeleton to the extracellular matrix?

A

It allows the cell to physically connect with protein structures outside the cell

111
Q

What is the function of the nucleus?

A

Contains chromosomes and controls protein expression

112
Q

What is the function of the rough endoplasmic reticulum?

A
  • ribosomes attached to the rough ER synthesise secretory (eg. glycoproteins) and membrane-bound proteins
  • rER produces the protein and enzymes in the lumen add carbohydrates
  • secretory proteins leave rER in vesicles and go to the golgi
113
Q

What is the function of the lysosome?

A

Fuse with incoming food vacuoles or unwanted/damaged organelles and break down/digest them

114
Q

What does the endomembrane system include?

7-8

A
  • nuclear envelope
  • endoplasmic reticulum (both smooth and rough)
  • Golgi
  • vesicles
  • lysosomes
  • vacuoles
  • plasma membrane
115
Q

What are the functions of the smooth ER? (4)

A
  1. metabolism (breaking down and putting together) of carbohydrates
  2. lipid synthesis for membranes
  3. detoxification of drugs and poisons
  4. storage of Ca2+ ions
116
Q

Can the amount of smooth ER be increased or decreased to meet demand?

A

Yes

117
Q

Proteins in vesicles leave the _______ in _________ and enter the ________ face of the __________

A

rough ER
vesicles
cis
golgi

118
Q

Describe the golgi including basic function

A
  • a series of membrane sacs and associated vesicles
  • has a cis and trans face of different polarities
  • receives, modifies, sorts and ships proteins arriving from the ER
119
Q

Vesicles from the ER arrive at the golgi at the _______ face

A

cis

120
Q

Processed vesicles leave the golgi at the _______ face

A

trans

121
Q

What are three functions of the golgi

A
  • glycosylation
  • sorting proteins
  • directing vesicle traffic
122
Q

Describe glycosylation

A
  • addition (or modification) of carbohydrates to proteins

- golgi also produces polysaccharides which may be excreted from the cell

123
Q

Describe the process of sorting proteins at the golgi

A

adding molecular markers to direct proteins to the correct vesicles before ‘budding’ from the trans face

124
Q

Describe the process of directing vesicle trafficking by the golgi

A
  • adds molecular tags to the vesicles to direct them to the correct target
  • these molecular tags act as docking sites when they reach their target
125
Q

What are the two methods of bulk transport across the plasma membrane?

A

Exocytosis

Endocytosis

126
Q

Describe exocytosis

A

transports materials (glycoproteins) out of the cell or to the cell surface

127
Q

What are two types of exocytosis?

A

Constitutive exocytosis

Regulated exocytosis

128
Q

Describe constitutive exocytosis

A

the unregulated release of extracellular matrix proteins

129
Q

Describe regulated exocytosis

A

the controlled release of hormones and neurotransmitters

130
Q

Describe endocytosis

A

The cell takes in molecules and particulate matter at the plasma membrane

131
Q

What are three types of endocytosis

A

Pinocytosis

Phagocytosis and Receptor-mediated endocytosis

132
Q

Describe pinocytosis

A

the non-selective uptake of cellular fluid containing various solutes such as proteins and sugars
the uptake vesicle is formed with the aid of a coat protein

133
Q

Describe phagocytosis

A

uptake of “food” particles into a vesicle with a phagocytic vacuole which is digested by lysosomes

134
Q

Describe receptor-mediated endocytosis

A
  • specialised/picky form of pinocytosis
  • allows the cell to take up bulk quantities of specific substances which may be present at only low concentrations in the extracellular fluid
  • receptor proteins selectively capture the required solute
135
Q

What do lysosomes contain

A

hydrolytic enzymes

136
Q

What sort of things does the lysosome break down (4) and where do they go?

A

proteins, lipids, carbohydrates and nucleic acids and then they are released into the cell

137
Q

The process of lysosomes breaking down unwanted cellular material is called

A

autophagy

138
Q

How are vacuoles important in plants?

A
  • they can perform lysosome-like functions

- the large central vacuole absorbs water allowing plants to grow without a large increase to the cytoplasm

139
Q

What is the cytoskeleton?

A

essentially the stuff that the organelles are floating in

140
Q

Describe the cytoskeleton including its function

A
  • helps maintain cell shape
  • helps position organelles within a cell
  • can rapidly assemble and disassemble
  • highly dynamic but provides stability
141
Q

What are the three main components of the cytoskeleton?

A
  • microtubules
  • microfilaments
  • intermediate filaments
142
Q

What are microtubules made of?

A

tubulin subunits

143
Q

Which of the components of the cytoskeleton can radiate out from an organising centre (centrosome)

A

microtubules

144
Q

Microtubules resist

A

compression

145
Q

Functions of microtubules

A
  • help maintain cell shape
  • can also help with motility
  • involved in vesicle/organelle motility
146
Q

Tubulin subunits are

A

proteins

147
Q

Give an example of how microtubules can help with motility

A

flagella

cilia

148
Q

Explain how microtubules help with vesicle/organelle motility

A
  • An ATP-powered motor protein attaches to the microtubule
  • this protein is also bound to a vesicle or organelle
  • when given ATP, the protein changes shape and ‘walks’ down the microtubule allowing movement of vesicles and organelles within a cell
149
Q

What are microfilaments made of?

A

actin subunits

150
Q

Microfilaments form

A
  • linear strands

- 3D networks (using branching proteins)

151
Q

Microfilaments resist

A

tension

152
Q

Functions of microfilaments

A
  • maintain cell shape
    can also help with
  • cell movement
153
Q

Explain how microfilaments can help resist tension and maintain cell shape

A

There is lots of tension around the edges of the cell but the 3D cortical network under the plasma membrane holds it together, helps make this region less fluid and helps maintain cell shape

154
Q

Explain how microfilaments can help with cell movement

A 
Interactions between actin and myosin 
This allows:
- muscle contraction
- amoeboid movement
- cytoplasmic streaming
155
Q

What are intermediate filaments made from?

A

various proteins such as

  • keratins (hair)
  • lamins (nucleus)
  • neurofilaments (neurons)
156
Q

Which of the components of the cytoskeleton form relatively permanent structures?

A

intermediate filaments

157
Q

What are the functions of the intermediate filaments?

A
  • maintain cell shape

- anchor organelles

158
Q

How are cells joined together?

A

cell junctions

extracellular matrix

159
Q

What are the three types of cell junctions?

A
  • tight junctions
  • gap junctions
  • desmosomes
160
Q

Describe tight junctions

A
  • hold neighbouring cells tightly together
  • cells ‘sewn’ together
  • prevents movement of fluid across cell layers
161
Q

Tight junctions prevent the movement of _______ across cell layers

A

fluid

162
Q

Describe desmosomes

A
  • anchoring junction
  • provides attachment between sheets
  • heavy duty
  • connected into the cell by intermediate filaments
163
Q

Desmosomes are connected into the cell by

A

intermediate filaments

164
Q

Describe gap junctions

A
  • a point of cytoplasmic contact between the two cells
  • allows ions and small molecules to pass from cell to cell
  • allows rapid intercellular communication
165
Q

What is the ECM composed of

A
  • material secretes by the cells

- most ECM proteins are glycoproteins

166
Q

What are glycoproteins?

A

proteins with added carbohydrates

big protein, little carbohydrate

167
Q

What is the most abundant ECM glycoprotein?

A

collagen

168
Q

What are collagen fibres embedded in?

A

proteoglycan complex matrix

169
Q

How do endocytosis and exocytosis relate to the addition and/or removal of materials from the plasma membrane?

A

Endocytosis:
Plasma membrane folds inwards, slowly ingesting substances or particles.
The membrane eventually buds off within the cytoplasm and brings items into the cell’s interior.
Exocytosis:
Secretory vesicles fuse with the plasma membrane, discharging the contents of the vesicle to the exterior of the cell.

170
Q

What is the approximate diameter of the microtubules?

A

25 nm

171
Q

What is the approximate diameter of the microfilaments?

A

7 nm

172
Q

What is the approximate size of the intermediate filaments?

A

8-12 nm

173
Q

What are proteoglycans?

A

Proteins with extensive sugar additions

little protein, big sugar

174
Q

What is the role of the proteoglycans in the ECM?

A

to trap water to help resist compression and therefore retain tissue shape

175
Q

Collagen in the most abundant glycoprotein. Name another glycoprotein

A

Fibronectins

176
Q

What is the purpose of fibronectins?

A

To attach the cells to the ECM

177
Q

What are integrins?

A

Membrane proteins

178
Q

What is the purpose of integrins?

A

To connect the ECM to the cytoskeleton

179
Q

Explain how integrins and fibronectins work together and describe their combined function

A

The integrin spans the plasma membrane which connect the cytoskeleton (inside) to the ECM (outside).
Fibronectins attach to the integrin (outside) which provides link between the cells and the ECM.
The two provide a communication link from ECM to the cell interior

180
Q

What makes up a plant cell?

A

The cell wall and the protoplast

181
Q

What is the protoplast?

A

The plasma membrane and everything inside it

182
Q

What is the cell wall made of?

A
  • cellulose
  • pectin
  • hemicellulose
  • extensin
183
Q

What is in the 1st phase of the (primary) cell wall?

A
  • cellulose
184
Q

What is in the 2nd phase of the (primary) cell wall?

A
  • pectin
  • hemicellulose
  • extensin
185
Q

What does cellulose form in the cell wall?

A

microfibrils

186
Q

What are the function(s) of pectin?

A

it binds water and has gel like properties

187
Q

What are the function(s) of hemicellulose?

A

helps form a rigid structure

188
Q

What are the function(s) of extensin?

A

Cross links between pectin and cellulose to dehydrate the cell wall which means it can become more rigid
(also allows it to grow)

189
Q

How is the primary cell wall synthesised?

A
  • cellulose microfibrils synthesised at the plasma membrane
  • pectin and hemicellulose come from the golgi and are transported to the plasma membrane in vesicles via exocytosis
  • extensin comes from the rough ER and is transported to the plasma membrane in vesicles via exocytosis
190
Q

What is the non-crystalline matrix?

A

Phase 2 (pectin, hemicellulose, extensin)

191
Q

Pectin and hemicellulose are examples of

A

polysaccharides

192
Q

Exensin is an example of

A

a cell wall protein

193
Q

What sort of exocytosis releases the extracellular matrix proteins in animals but pectin, extensin and hemicellulose in plants?

A

constitutive exocytosis

194
Q

What are the functions of the cell wall?

A
  • cell shape
  • structural support (protoplast pushing against the cell wall)
  • prevents excessive water uptake
195
Q

Describe how the cell wall helps with structural support

A

The protoplast pushes against the cell wall

  • in young cells, this helps it grow
  • in mature cells, the extensin cross linking helps keep the cell rigid and stops it from bursting
  • loss of water causes wilting
196
Q

Describe how the cell wall prevents excessive water uptake

A

The water enters the cell by osmosis (into the central vacuole) and the protoplast expands and pushes against the cell wall.
Pressure from the cell wall limits the volume of water that can be taken up.

197
Q

How are vacuoles important in the prevention of excessive water uptake?

A

they contain water and make up such a large portion of the protoplast

198
Q

What is a vacuole?

A
  • an organelle surrounded by a single membrane

- it is highly selective and controlling

199
Q

What is osmosis?

A

The movement of water across a selectively permeable membrane from where there is a low solute concentration to where there is a high solute concentration

200
Q

In a hypotonic solution, an animal cell can become

A

lysed

201
Q

In a hypertonic solution, an animal cell can become

A

shrivelled

202
Q

In an isotonic solution, a plant cell can become

A

flaccid

203
Q

In a hypertonic solution, a plant cell can become

A

plasmolysed

204
Q

Not all plants have a

A

secondary cell wall

205
Q

When is the secondary cell wall produced?

A

once the cell is grown

206
Q

How many layers does the secondary cell wall have?

A

3

207
Q

What are the chemical characteristics of the secondary cell wall?

A

More cellulose
Less pectin
lignin

208
Q

What is lignin?

A

A complex polymer that confers strength and rigidity to the secondary cell wall and acts to exclude H2O

209
Q

What is the function of the secondary cell wall?

A

It provides structural support for specific cell types such as water transferring cells, and for the whole plant

210
Q

How do plant cells communicate?

A

Via the plasmodesmata

211
Q

What are plasmodesmata?

A

Intercellular connections that allow cell to cell communication by allowing free exchange of small molecules

212
Q

How do plants get their energy?

A

Through the process of photosynthesis

213
Q

Why do cells need energy?

A
  • mechanical work
  • to make new materials
  • for transport
  • to maintain order
214
Q

Why would cells need to do mechanical work?

A

To move proteins and vesicles

215
Q

Why would cells need to make new materials?

A

for growth and replacement

216
Q

What would cells need to transport?

A

molecules across the membrane

217
Q

Where does respiration take place?

A

in the mitochondria

218
Q

Describe the mitochondria

A
  • 1-10 μm
  • 1-1000 per cell
  • contains mitochondrial DNA and ribosomes
219
Q

How many membranes does the mitochondria have?

A

2

220
Q

Where is the mitochondrial matrix?

A

inside the inner membrane of the mitochondria

221
Q

What are the cristae?

A

the highly folded inner membrane of the mitochondria

222
Q

What is the inter membrane space?

A

The space in between the two membranes of the mitochondria

223
Q

What is the purpose of cellular respiration?

A

to harvest chemical energy from glucose

224
Q

What are the three stages of respiration?

A
  1. glycolysis
  2. pyruvate oxidation and citric acid cycle
  3. oxidative phosphorylation
225
Q

Where does glycolysis occur?

A

in the cytosol

226
Q

What is broken down in glycolysis?

What is formed?

A
  • Glucose is converted to two lots of a 3C molecule called pyruvate
  • it also generates 2ATP
  • electrons are transferred to the high energy electron carrier (NAD+) making NADH
227
Q

Where does pyruvate oxidation and citric acid cycle take place?

A

In the mitochondrial matrix

228
Q

Describe pyruvate oxidation and the citric acid cycle

A
  • pyruvate is converted to acetyl CoA
  • acetyl CoA enters the citric acid cycle
  • output is ATP and high energy electron carriers NADH and FADH2
229
Q

Oxidative phosphorylation consists of what two stages?

A

The electron transport chain

Chemiosmosis

230
Q

Describe the electron transport chain

A
  • electron carriers NADH and FADH2 shuttle high energy electrons to the inner mitochondrial membrane
  • the e- move through protein complexes embedded in the inner membrane
  • as the e- move, H+ are pumped across the membrane from the mitochondrial matrix into the intermembrane space
  • H+ accumulate in the intermembrane space, creating a concentration gradient
  • this initiates chemiosmosis
231
Q

Where does oxidative phosphorylation take place?

A

The cristae

232
Q

Describe the process of chemiosmosis

A
  • H+ goes through ATP synthase (embedded in the inner mitochondrial membrane) from the intermembrane space into the mitochondrial matrix
  • this allows ATP synthase to convert ADP to ATP
233
Q

What is an advantage of using ATP for energy?

A

it enables the controlled release of energy

234
Q

Where does photosynthesis take place?

A

The chloroplasts

235
Q

Describe the structure of the chloroplast

A
  • outer membrane
  • intermembrane space
  • inner membrane
  • stroma
  • granum
  • thylakoid
  • thylakoid space
236
Q

A stack of thylakoids is called a

A

granum

237
Q

Inside each thylakoid is the

A

thylakoid space

238
Q

Inside the inner membrane where the DNA, ribosomes and thylakoids are, is called the

A

stroma

239
Q

Photosynthesis consists of what two processes?

A

light reactions

Calvin cycle

240
Q

What is the purpose of the light reactions?

A

capturing light energy to convert it into chemical energy

241
Q

Describe the light reactions

A
  • light energy is absorbed in by chlorophyll (contained in photosystems inside the thylakoid membrane)
  • this excites electrons
242
Q

The nucleus is surrounded by the

A

nuclear envelope

243
Q

The nuclear envelope consists of how many membranes?

A

2

244
Q

What is the purpose of the nuclear pore complex

A

It controls the movement of molecules in or out of the nucleus

245
Q

What needs to leave the nucleus?

A

mRNA
tRNA
ribosomal subunits

246
Q

What needs to enter the nucleus?

A

control signals (like when to turn a gene on or off)
building materials
energy for chemical synthesis

247
Q

What is the inner surface of the nucleus lined with?

A

the nuclear laminar

248
Q

Describe the nuclear laminar

A

It is the inner surface of the nucleus which is composed of intermediate filaments.
It helps maintain the shape of the nucleus and to organise the packing of the DNA within the nucleus

249
Q

What is the nucleolus?

A

A prominent nuclear structure within non-dividing cells and it is responsible for making rRNA (combines with proteins to produce ribosomes)

250
Q

The DNA helix twists around proteins called

A

histones (H2 and H4)

251
Q

The DNA helix twists around proteins called histones (H2 and H4) which forms a strand of “beads”. Each bead is called a

A

nucleosome

252
Q

The DNA helix twists around proteins called histones (H2 and H4) which forms a strand of nucleosomes. The DNA continues to wrap around which histones?

A

H1

253
Q

What is euchromatin?

A

less dense DNA

it contains genes being used by that cell

254
Q

What is heterochromatin?

A

more dense DNA

contains genes not being used by that cell

255
Q

Where does carbon fixation/Calvin cycle take place?

A

In the stroma

256
Q

Where do the light reactions take place?

A

In the thylakoid membranes

257
Q

Describe the light reactions

A
  • in a continuous loops, water is split into O2 and H+ to give e-
  • the e- are in chlorophyll in photosystem || where light energy absorbed by the chlorophyll excites them
  • the e- move through the cytochrome complex which allows H+ to move from the stroma across the thylakoid membrane into the thylakoid space
  • the e- move through photosystem | and then into a complex to convert NADP+ and H+ into the e- carrier NADPH
  • the H+ in the thylakoid space go through ATP synthase back to the stroma to generate ATP
258
Q

What are photosystems?

A

protein complexes that contain chlorophyll

259
Q

What is the equation for photosynthesis?

A

6CO2 + 6H2O -> C6H12O6 + 602

260
Q

What is the equation for respiration?

A

C6H12O6 + 602 -> 6CO2 + 6H2O + energy

261
Q

What are the inputs of photosynthesis?

A

light
H2O
CO2

262
Q

What is produced during the light reactions of photosynthesis and what are these used for?

A

ATP and NADPH to be used in the Calvin Cycle

263
Q

What are the outputs of photosynthesis?

A

O2 and C6H12O6

264
Q

What are the three stages of the Calvin Cycle?

A

Fixation
reduction
regeneration

265
Q

Describe carbon fixation stage of the Calvin Cycle

A

one at a time, three CO2 molecules bind to RUBP to form a total of three unstable 6C chains. These break into six 3C chains
this uses ATP (total 6ATP -> 6ADP)

266
Q

Describe reduction stage of the Calvin Cycle

A

Each 3C molecule is converted into another 3C molecule called G3P
six NADPH are each converted into NADP+

267
Q

Describe regeneration stage of the Calvin Cycle

A

the other five G3P will be converted back into three RUBP molecules to restart the cycle
this uses ATP (total 3ATP -> 3ADP)

268
Q

What enters the Calvin cycle?

A

3 x CO2
9 x ATP
6 x NADPH

269
Q

What exits the Calvin cycle?

A

1 x G3P (every three turns)
3 x ADP
6 x NADPH

270
Q

How did chloroplasts and mitochondria originate?

A

An ancestral prokaryote engulfed an aerobic bacteria and tamed them and they became the mitochondria and the chloroplasts

271
Q

Name two regulatory lipids derived from cholesterol

A

Testosterone and Oestrogen

CELS 191 (5 decks)

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