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Cells Flashcards

(110 cards)

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1
Q

Science is

A

knowledge based on experimentation

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2
Q

Can science answer all the questions?

A

No.

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3
Q

Scientific method

A

1) Observation and facts
2) Hypotheses and predictions
3) Testing
4) Evaluation and interpretation of results
5) Conclusions

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4
Q

What did Semmelweis notice about childbed fever?

A

He noticed that in division 1, which was next to the autopsies library, that when he asked workers to wash their hands with chlorine, the incidents of childbed fever declined.

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5
Q

Other theories about childbed fever that were disproved by Semmelweis

A

Male doctors - rougher
Miasma - bad smell
Birthing position - laying on their back

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6
Q

Unit of life is

A

the cell

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7
Q

inside the cell, life does what?

A

performs all the chemical reactions necessary to avoid decay into equilibrium

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8
Q

Where do cells get the material to make their parts?

A

From the environment.

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9
Q

How old is the Earth?

A

4.5 billion years old

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10
Q

How many eons are there, and what are they?

A

Four eons:

1) Hadean
2) Archaean
3) Proterozoic
4) Phanerozoic

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11
Q

Hadean

A

No life

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12
Q

Archean

A

3.8 billion years ago - from fossils and the presence of oxygen, we know there were prokaryotic cells - single celled organisms like Archaeans and Bacteria

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13
Q

Proterozoic

A

emergence of Eukaryotic cells - still single celled

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14
Q

Phanerozoic

A

Cambrian explosion - macro-fossils - multi-celled organisms

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15
Q

All cells have what in common?

A

1) cell membrane
2) DNA chromosomes
3) ribosomes for protein synthesis
4) Cytoplasm in the cell
5) Energy transformation pathways
6) 500 genes shared between all domains of life

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16
Q

Cell membrane functions

A

1) Controls movement of ions and molecules, maintaining chemical environment inside the cell.
2) encloses the cytoplasm
3) organize enzymes
4) Detect and allow responses to signals from the environment
5) Promotes recognition and adhesion between cells and the extracellular matrix.

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17
Q

Cytoplasm

A

Watery environment where cellular structures are organized and all chemical reactions take place

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18
Q

Energy transformation pathways

A

Metabolic pathways that allow cells to utilize energy from the environment to fuel metabolism

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19
Q

Differences between prokaryotes and eukaryotes

A

1) Prokaryotes have no nucleus
2) Prokaryotes have no endomembrane system (ER, Golgi, lysosomes)
3) Prokaryotes have no mitochondria or chloroplasts
4) Prokaryotes have a peptidoglycan wall.
5) Eukaryotes have a cytoskeleton

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20
Q

Eukaryotes’ size in comparison to prokaryotes

A

Eukaryotes are on average 10 times larger than prokaryotes.

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21
Q

Purpose of enzymes

A

Act as catalysts - speed up reactions

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22
Q

Characteristic of cell membranes that is essential to life

A

they are semi-permeable.

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23
Q

Membranes are made of:

A

Phospholipid bilayer

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24
Q

Phospholipid structure

A

They are amphipathic. They have a head that is hydrophilic and tails that are hydrophobic.

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25
Permeability of phospholipid bilayer
Small, non-polar molecules (oxygen) pass through rapidly Small, polar molecules (H2O) pass through slowly Large, non-polar/polar molecules (glucose, ions) cannot pass through
26
how do large molecules get into the cell?
Through transport (integral) proteins.
27
What substance is essential for the permeability of the membrane?
Cholesterol
28
Passive transport
Follows concentration gradient and does not require energy
29
Active transport
Does not follow concentration gradient - therefore requires energy
30
Head of phospholipid has what substance?
phosphate - negatively charged - thus soluble in water
31
Functions of transmembrane proteins
1) Transport 2) Signal transduction 3) Enzymatic activity 4) Intracellular joining 5) Cell Cell recognition
32
Signal Transduction
Cell communication
33
Proteins that do signal transduction are called
receptors
34
Prokaryote alternative to nucleus
nucleoid region
35
Black dots in image of prokaryote
Ribosomes
36
Towards center of prokaryote, there is:
DNA
37
Structure of eukaryotic nucleus
Membrane bound - also has nucleolus
38
RNA located where in eukaryotic cell?
Inside nucleolus
39
how do things enter and exit the nucleus?
Through pores
40
Function of nucleus
House DNA, site of transcription
41
Function of nucleolus
make ribosomes and store RNA
42
Bacterial cytoplasm composition
70% water, 30% proteins, nucleic acids, etc.
43
Nuclear lamina
network of protein fibers that give the nucleus its shape (else it will collapse)
44
Mitochondria
Site of ATP synthesis
45
How many membranes does the mitochondria have?
2 - an inner and outer membrane.
46
Plant cell wall made of
cellulose.
47
Cellulose
polymer of glucose
48
Two types of Bacterial Cell wall
1) Peptidoglycan - in both Gram + and Gram - bacteria | 2) Lipopolysaccharide - outer wall found in gram - bacteria
49
Cell wall does what for bacteria
Protects it and helps it attach to substrates.
50
How does penicillin kill bacteria?
By suppressing the bacterial enzyme necessary for cell wall synthesis - causes bacteria to explode
51
How does our immune system recognize bacteria?
through molecules that recognize peptidoglycan and lipopolysaccharide.
52
Do animal cells have a cell wall?
No, they have a plasma membrane.
53
Cytoskeleton functions:
Helps cells move and determines its structure
54
Cytoskeleton
highly organized protein fibers
55
Do all cells have a cytoskeleton?
yes, both prokaryotes and eukaryotes have a cytoskeleton, but it is less developed in prokaryotes
56
Parallel cytoskeletal fibers act like what?
rails
57
Components of cytoskeletal fibers
1) Actin cortex 2) microtubules 3) intermediate filaments
58
Actin cortex made up of...
polymers of actin proteins.
59
Microtubules made up of...
polymerization of alpha and beta tubulin proteins (can make it longer and shorter by adding monomers)
60
Intermediate filaments made up of...
up to 70 proteins.
61
microtubule size relative to actin filaments
much larger
62
Microtubule location inside the cell
Extend throughout the cell.
63
What synthesizes proteins?
Ribosomes
64
Ribosome composition
Made up of both proteins and RNA. Has a large and small subunit.
65
Are the ribosomes in prokaryotes and eukaryotes the same?
no.
66
Used to color specific structures in cells, by attaching it to a protein or molecule that binds to a specific region
Fluorophore
67
Endomembrane system function
Involved in the synthesis and delivery of molecules
68
Parts of endomembrane system
1) Endoplasmic reticulum (Smooth and rough) 2) Golgi Apparatus 3) Lysosomes 4) exocytic vesicles 5) endosomes
69
Smooth ER
Lacks ribosomes, involved in synthesis of lipids
70
Rough ER
Has ribosomes attached, looks like interconnected flattened sacs. Makes proteins that are inserted in the plasma membrane, or are shipped elsewhere. Makes more membrane.
71
Pathways of proteins made in ER
transmembrane (inserted in membrane) or secreted
72
All elements of endomembrane system have what?
Phospholipid bilayer
73
Function of golgi apparatus
prepares proteins and molecules for transport to membrane or to be secreted through vesicles
74
for transmembrane transport, what does the golgi attach to the protein?
Sugar
75
How do the transport and secretory vesicles know where to go?
Guided by cytoskeleton. (they walk on it)
76
Ribosomes attached to rough ER do what?
Synthesize proteins, inserting them into the lumen of the ER.
77
What does the ER do with synthesized proteins?
ER transports the proteins to Golgi using transport vesicles.
78
As transport vesicle and golgi apparatus touch, what happens?
They fuse. Protein added to golgi.
79
What do free floating ribosomes (not attached to any organelle) do?
They make proteins only used within the cell (no transport needed).
80
Endocytosis
For large things - Cell eats something, forming an endosome.
81
how do cells digest what it eats through endocytosis?
cells digest using lysosomes, which contain acids. The lysosomes fuse with the endosome.
82
phagocytosis
White blood cells (phagocytes) eating bacteria
83
Exocytosis
Vesicle leaving the cell. Like when secretory vesicles from Golgi allow proteins to be secreted from the cell
84
Lysosomes' functions
Digest food, destroy invaders, dispose of ailing mitochondria or chloroplasts
85
in which cells are mitochondria present?
All eukaryotic cells, including plant cells.
86
How many mitochondria are in a cell?
Varies. Can have thousands.
87
mitochondria responsible for what type of respiration?
Aerobic respiration.
88
inner membrane of mitochondria texture:
has folds or invaginations
89
outer membrane of mitochondria texture:
smooth
90
Which enzyme adds phosphate to ADP?
ATPase
91
How many membranes do chloroplasts have?
2
92
how do chloroplasts get energy?
through photosynthesis
93
Both mitochondria and chloroplasts have what? What does it do?
have double membrane. Inter-membrane space essential for creation of proton gradient - ATPase is door. Energy from proton gradient used for ATP synthesis during aerobic respiration and photosynthesis.
94
Where do prokaryotes create a proton gradient, since they do not have chloroplasts and mitochondria?
In between cell wall and plasma membrane
95
Before oxygen, we had to have what?
photosynthesis in prokaryotes
96
Which bacteria can perform photosynthesis?
cyanobacteria
97
After the development of photosynthesis, what happened?
Oxygen revolution - O2 rises dramatically
98
Which cells adapted to use O2?
Eukaryotes.
99
Advantage of aerobic respiration in eukaryotes
Produced many more ATP from 1 glucose
100
is there such a thing as an anaerobic eukaryote?
No.
101
Three domains of life:
Bacteria, Archaea, Eukarya
102
First branching
Between prokaryotes - bacteria and Archaea - unicellular
103
We're closer to which domain of life (besides eukaryotes)? Why?
archaea - we branched from them
104
Origin of nuclear membrane and endomembrane system
There was an evolutionary incentive to growing larger - larger cells could eat bacteria and other smaller things. As cells grew larger, invaginations were created, forming the nuclear membrane (nucleus) and endomembrane system.
105
Main theory for origin of mitochondria and chloroplasts
Endosymbiotic theory
106
Endosymbiotic theory
Larger anaerobic eukaryotes engulfed aerobic prokaryotes - became mitochondria and chloroplasts that allowed host cell to become aerobic.
107
Theorized ancestor of mitochondria
Rickettsia - typhus causing bacteria that needs a host cell
108
Evidence supporting endosymbiotic theory
1) Mitochondria and chloroplasts are the right size 2) Their inner membranes have enzymes and a transport system that resembles those found in the plasma membranes of modern prokaryotes 3) They replicate through a process resembling binary fission - eukaryotes divide through mitosis 4) have circular chromosome not associated with histones 5) Have their own rRNA, ribosomes, and other equipment needed to transcribe and translate their DNA into proteins.
109
Eukaryotes have taken what from Archaeans?
information processing (copying DNA)
110
Eukaryotes have taken what from Prokaryotes?
Protein and ATP synthesis (housekeeping)

Core Biology (2 decks)

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