Midterm content Flashcards
1
Q
What microscope is used to see cells and smaller objects?
A
Light microscope
2
Q
What forms a light microscope?
A
a lens and light
3
Q
Which microscope is used for studying organelles?
A
Transmission electron microscope
4
Q
Which microscope is used for studying surface structure?
A
Scanning electron microscope
5
Q
What is a macromolecule?
A
A polymer of smaller molecules
6
Q
What are the 4 kinds of macromolecules?
A
Polysaccharides, proteins, nucleic acids, lipids (lipids are not real macromolecules)
7
Q
How do molecules grow?
A
Dehydration reactions
8
Q
How do you break down molecules?
A
Hydrolysis
9
Q
What are polysaccharides and disaccharides held by?
A
Glycosidic linkage bonds
10
Q
What are polysaccharides?
A
Polymers built of many monosaccharides, structural and storage
11
Q
What are structural polysaccharides used for?
A
To build strong materials ex: exoskeleton
12
Q
What are storage polysaccharides used for?
A
Store sugar in the form of storage polysaccharides (plants- starch, humans-glycogen)
13
Q
what are lipids?
A
Diverse group of hydrophobic molecules: Consist of phospholipids, steroids, fats
14
Q
What are fatty acids formed of?
A
Hydrocarbon chain, carbon at one end is part of carboxyl group
15
Q
What is a fat?
A
constructed from two smaller molecules: fatty acid and glycerol
16
Q
triacyglycerol?
A
3 fatty acids, 3 glycerol molecules
17
Q
What is a phospholipid?
A
two fatty acids attached to glycerol, one hydroxyl group attached to phosphate
18
Q
What is a saturated phospholipid?
A
no double bonds, completely surrounded by Hydrogen (solid)
19
Q
What is an unsaturated phospholipid?
A
Double bond, cinched, hydrogen cannot completely surround it (liquid)
20
Q
What is a phospholipid bilayer?
A
a hydrophilic double membrane (head is hydrophilic, tail is hydrophobic)
21
Q
Explain how DNA is transcribed
A
DNA (transcription) - RNA (translated)- amino acid chain (folding) - protein
22
Q
What are some uses for proteins?
A
Enzymes, antibodies, storage proteins, etc..
23
Q
What are amino acids composed of?
A
Organic molecules with an amino group and a carboxyl group, have side chains of amino acids, join to create polypeptides
24
Q
Which bonds hold proteins together?
A
Peptide bonds
25
How many amino acids are there?
There are 20 different kinds, each chain varies in order which can produce many many different proteins
26
What are the 4 levels of protein structure?
1. Primary
2. secondary
3. Tertiary
4. Quaternary
27
What occurs in the 1st phase of protein structure?
Amino acids bond to form polypeptides
28
What happens in the 2nd phase of protein structure?
Secondary: hydrogen bonds stabilize regions (Alpha helix and beta pleated sheet)
29
What happens in the 3rd phase of protein structure?
Tertiary: Protein structure forms
30
What are nucleic acids?
Acids involved in the production and synthesis of DNA and cell division
31
What forms nucleic acids?
Ribose/deoxyribose, phosphate, sugar (backbone)
32
Describe DNA
Double helix strand, hydrogen bonds formed between nitrogenous bases, 5' to 3'
33
Describe RNA
Single strand, bonds with itself,
34
What is a eukaryotic cell?
Contains internal membranes that compartmentalize their functions, DNA is in nucleus
35
What is a prokaryotic cell?
Lacks a true nucleus, much simpler internal structure, dan concentrated in nucleoid
36
What is the cytoplasm?
The region between the nucleus and the plasma membrane
37
What is the plasma membrane/membrane of organelles?
Consists of a phospholipid bilayer, with proteins embedded/bobbing in it, carbs attached
38
What does it mean to be amphipathic?
Has water loving/hating regions ie: phospholipid
39
Where does transcription occur?
the nucleus
40
Where does translation occur?
The cytoplasm
41
What is the nuclear envelope?
Encloses the nucleus, composed of two membranes, one porous layer that allows proteins and RNA through
42
What is the nucleolus?
Where ribosomal RNA is synthesized
43
What are ribosomes?
Complexes made of ribosomal RNA and proteins: carry out protein synthesis
**remember that to synthesize protein uses mrna, rrna, and trna
44
What are the two types of ribosomes?
Free ribosomes and bound ribosomes *structurally identical
45
What are free ribosomes?
Suspended in cytosol, creates proteins for the cell
46
What are bound ribosomes?
Attached to the outside of endoplasmic reticulum and nuclear envelope, creates proteins for membrane and out of the cell
47
What is the endosymbiont theory?
Early prokaryotic cells that were absorbed by the cell ex: mitochondria: oxygen using non photosynthetic prokaryotic cell absorbed
48
What is the mitochondria?
Sites of cellular respiration, turns sugar into energy
49
What are chloroplasts?
Found in plants, photosynthesize, contain plastids and chloroplasts, contain a 3rd membrane: thylakoid membrane
50
What is a peroxisome?
Contains enzymes that produce H2O2
- break down harmful things, removes Hydrogen, and adds to oxygen
51
What is the endomembrane system?
Regulates protein traffic and performs metabolic functions
52
What forms the endomembrane system?
Nuclear envelope
The endoplasmic reticulum (rough/smooth)
The golgi apparatus
Lysosomes
Vesicles and vacuoles
Plasma membrane
53
What is the endoplasmic reticulum?
Network of membranous tubules and sacs called cisternae
54
What are the two kinds of ER?
Smooth and rough
55
What does the smooth ER do?
outer surface lacks ribosomes, functions in diverse metabolic processes
56
What does the rough ER do?
-Studded with ribosomes
- makes proteins to be secreted, and membrane proteins
57
How do proteins leave the ER?
Through transport vesicles from the rough er to the cis face of the Golgi apparatus
58
What is the Golgi apparatus?
The 'shipping and receiving centre', consists of flattened membranous sacs called cisternae, not physically connected, different enzymes that do different modifications
59
How do proteins leave the Golgi?
Through transport vesicles, molecular identification tags that lead it to the correct part of the membrane
60
What are lysosomes?
Membranous sacs of hydrolytic enzymes that eukaryotic cells use to digest macromolecules
61
What is phagocytosis?
-Food vacuole surrounds food and smaller organisms, lysosome fuse to this vacuole whose enzymes digest this food
62
What is autophagy?
Damaged organelles become surrounded by a double membrane which fuses with lysosome to be digested
63
What are vacuoles?
large vesicles derived from the endoplasmic reticulum and Golgi apparatus
64
What is the cytoskeleton?
A network of fibres that organizes structures and activity in the cell
- provides mechanical support/maintains its shape
Dynamic: Can change the shape of the cell
64
What is the contractile vacuole?
Pumps excess water out of the cell to maintain a suitable concentration
65
What is a microtubule?
The thickest of the 3, tube shaped, made from dimers (alpha and beta tubulin)
- constructed from a globular protein called tubulin
- the beta end is the 'positive end', grows and shrinks faster
- Shapes and support the cell, serves as tracks along which organelles can move (if they have motor proteins)
66
Where do microtubules grow from?
The centrosome
66
What are some common things that microtubules can form?
Cilia: power and recovery strokes
Flagellum: undulating motions like the tail of a fish
66
What motor protein do microtubules use to move?
Kinesins: they move vesicles and organelles along microtubules
66
Which motor protein do microfilaments use?
Myosin: sliding of myosin along acting stimulates muscle contraction
66
What are the 3 main types of cell junctions?
tight junctions, desmosomes, Gap junctions
66
What is ATP?
Adenosine triphosphate, used for cellular work
66
What is the extracellular matrix?
Animal cells lack a cell wall but do have an ECM,
Integrins connect the ECM to the cell
66
What are microfilaments?
the thinnest of the types, built from molecules of actin
66
What does anabolic mean?
Synthesis of more complex compounds, energetic (requires energy)
66
What are intermediate filaments?
Middle sized
- Keratin is most common, only found in some animals
66
what is a tight junction?
Prevent fluid from moving across a layer of cells (waterproof)
67
What is a desmosome?
Strong connections between cells, connected to intermediate filaments, 'fasten' cells together
67
What kinds of cellular work is ATP used for?
Transport, mechanical, chemical
67
What are gap junctions?
used for 'communication'
allows for transfer of ions, amino acids, sugars to pass through
67
What does phosphorylate mean?
ATP is a renewable resource, can be regenerated by addition of phosphate to ADP.
67
What does catabolic mean?
A disassembly of complex molecules, exergonic: releases energy
67
Where does the energy to phosphorylate come from?
Comes from the exergonic reactions in the cell (releases energy, this energy is used to phosphorylate)
67
What are enzymes?
macromolecules that act as a catalyst but not consumed
67
What is the substrate?
the reactant an enzyme acts on
67
What is the active site?
a pocket/groove on the surface of the enzyme where the enzyme binds
68
What is a catabolic pathway?
a metabolic pathways that release stored energy by breaking down molecules
69
What is glycolysis?
occurs in the cytosol, breaks glucose into two molecules of a compound called pyruvate
70
What happens to pyruvate?
Enters the mitochondria and is oxidized into acetyl CoA which enter the citric acid cycle
71
What happens in the citric acid cycle after pyruvate is oxidized?
The energy yielding oxidation is complete
72
What happens to the hydrogen molecules after the citric acid cycle?
The hydrogen atoms are passed 1st to an electron carrier
73
What is the electron carrier called?
NAD+ which turns into NADH
74
What are dehydrogenases?
Enzymes that remove a pair of hydrogen from the substrate
75
What is the electron transport chain used for?
A series of proteins that pass electrons from NADH to oxygen while accumulating hydrogen protons across a membrane
76
NOTE** ATP synthase uses the energy of ion gradient like a water mill. A flow of hydrogen concentrates ADP and phosphate molecules in the membrane to form ATP
Power source come from hydrogen ion gradient
77
What is a genome?
A cell's DNA, genetic info (sex cell)
78
What is chromatin?
A mixture of DNA and proteins that form chromosomes
79
What is a nucleosome?
Basic repeating subunit of chromatin packaged in the cell's nucleus
80
Explain the structure of chromosomes?
chromosomes, nucleosomes, chromatin
81
What is the cell cycle and it's steps?
A series of events that take place as a cell grows and divides
- M, G1, S, G2
82
What are duplicated chromosomes called?
They are called sister chromatids
83
What is a centromere?
A region in the chromosome where chromatics are attached most closely
84
What is interphase?
G1-first gap, S-synthesis, G2- second gap
85
What is chromatin?
When a cell isn't dividing, the chromosomes in a long thin chromatin fibre
chromatin also forms subunits of nucleosomes which form chromosomes
86
What is the M phase?
Both mitosis and cytokenesis occur here
87
what is mitosis?
The division of genetic material in the nucleus
88
What are the 5 stages of mitosis?
1. Prophase: centrosome move away from each other
2. prometaphase: nucelar envelope dissapears, chromosomes even more condensed, microtubules grow and attach to chromsomes
3. Metaphase: Centrosomes now are opposite sides of cell, chromosomes lined up in the middle of the cell
4. Anaphase: New daughter chromosomes pulled apart
5. telophase: two daughter nuclei form, mitosis complete
89
What is the mitotic spindle?
Structure consists of fibres made of microtubules and proteins
- lines up chromosomes, formed during anaphase
90
What is a kinetochore?
A structure made of proteins, holds at the centre of a sister chromosomes
91
What is cytokinesis?
Cytoplasm divides to form two daughter cells, the 'cleavage furrow'
92
What regulates the cell cycle?
regulated by a molecular control system composed of cyclin and cyclin-dependant kinases
93
What is a kinase?
An enzyme that adds phosphate groups to other molecules and modulates protein functions
94
How do cyclin dependant kinases activate?
must be attached to cyclin, acts as the go ahead signal
95
Why does CDK concentration rise and fall?
It's dependant on cyclin concentrations which fluctuates
96
Which nitrogenous base binds with which? Adenine, Thymine, C and uracil
C with T, A with U
97
What are cisternae?
pockets that compose the Golgi apparatus and endoplasmic reticulum
98
What are cristae?
Small grooves on the interior membrane of the mitochondria
99
What are ribosomes composed of?
Apart from the trna, mrna, and rrna, the ribosomes are made up of small and large subunits (large on 'top', small on 'bottom')
100
What is generally bonded to proteins that leave the cell once synthesized?
Carbohydrates
101
What is the extracellular matrix composed of?
Glycoproteins and carbohydrate molecules
102
What holds the ECM to the cell?
Integrin
103
How is energy from ATP released?
Through hydrolysis (breakdown releases energy)
104
How do unicellular organisms identify mates?
Through chemical signalling. Each cell type secretes a mating factor that hinds to the receptors on the other cell.
105
What is quorum sensing?
Bacterial cells secrete molecules that can be detected by other bacterial cells. Sensing the concentration of signalling molecules allows bacteria to monitor local density of cells called quorum sensing.
106
What is the communication between direct cells?
type of local signalling ex: gap junctions (communication between adjacent cells)
107
What are cell junctions?
Allows for molecules to pass between cells
108
What is cell-cell recognition?
Two cells in an animal cell communicate by interaction between molecules protruding from their surfaces
109
What is paracrine signalling?
Another type of local signalling, molecules are secreted by the signalling cell and these molecules travel short distances.
110
What is synaptic signalling?
A type of local signalling occurring in the animal nervous system
111
What are the different kinds of local signalling?
Synaptic signalling, paracrine signalling, gap junctions,
112
What type of signalling stimulates muscle contraction?
Synaptic signalling (includes synaptic signalling between a muscle and neuron)
113
What is long distance signalling?
When hormones are secreted to travel long distances to stimulate a signal in other regions of the body
114
What are the 3 cell signalling stages?
Signal reception, signal transduction, cellular response
115
What is reception?
A signalling molecule binds to a receptor protein causing it to change shape
116
How do certain signalling molecules perform a signal without entering the cell?
Most water soluble signalling molecules bind to specific sites on transmembrane receptor proteins that transmit information from the extracellular environment to the inside of the cell
117
How is GTP bound?
A G protein coupled receptor (GPCR) works with the help of a G protein
118
What is GTP?
Similar to ATP, primarily used for signalLING
119
What is a kinase?
An enzyme that catalyzes the transfer of phosphate groups
119
What is an RTK?
Receptor Tyrosine Kinases belong to a major class of plasma membrane receptors characterized by having enzymatic activity
120
What is phosphorylation?
A mechanism for regulating protein activity. Activates or inactivates proteins. (adds a phosphate to a molecule)
121
Where are intracellular receptors found?
Found in the cytoplasm or nucleus of target cells
122
What is transduction?
Cascades of molecular interactions relay signals from receptors to target molecules in the cell
123
What happens in a phosphorylation cascade?
Series of proteins are phosphorylated, each protein adding a phosphate group to the next one in line
124
What is the purpose of an enzyme cascade?
Amplifies the cell's response to a signal
125
What is the response stage?
Cell signalling leads to regulation of transcription or cytoplasmic activities (many pathways regulate protein synthesis, turning on or off in the nucleus)
