Biochemistry Flashcards
(67 cards)
1
Q
Discovery of cells
A
Robert Hooke (mid-1600s)
- Observed sliver of cork
- Saw “row of empty boxes”
- Coined the term ‘cell’
2
Q
Cell Theory
A
The Cell Theory states that:
- All organisms are made up of one or more cells and the products of those cells.
- All cells carry out life activities ( require energy, grow, have a limited size).
- New cells arise only from other living cells by the process of cell division.
3
Q
Characteristics of All Cells
A
- A surrounding membrane
- Cytosol – cell contents in thick fluid
- Organelles – structures for cell function
- Nucleus - Control center with DNA
4
Q
Prokaryotic Cells
A
- First cell type on earth
- Cell type of Bacteria and Archaea
- Prokaryotic cells are cells without membrane bound organelles
- The DNA in prokaryotic cells is in the cytoplasm rather than enclosed within a nuclear membrane.
- Prokaryotic cells make single-celled organisms, such as bacteria……are all single-celled organisms prokaryotic?
- Organisms with prokaryotic cells are called prokaryotes.
- Nucleoid = region of DNA concentration
5
Q
Eukaryotic Cells
A
- Eukaryotic cells are cells that contain membrane bound organelles
- Eukaryotic cells are usually larger than prokaryotic cells, and they are found mainly in multicellular organisms.
- Organisms with eukaryotic cells are called eukaryotes, and they range from fungi to people. - are there single celled fungi?
- Nucleus bound by membrane
- Include fungi, protists, plant, and animal cells
- Possess many organelles
6
Q
Plant vs Animal Cells
A
-The main structural differences between plant and animal cells lie in a few additional structures found in plant cells.
These structures include:
- Chloroplasts
- the cell wall
- A large central vacuole.
7
Q
2 types of Organelles
A
Bacteria like organelles:
- Derived from symbiotic bacteria
- Ancient association
- Endosymbiotic theory
- mitochondria and chloroplasts
plasma bound membranes:
- Contains cell contents
- Double layer of phospholipids & proteins
8
Q
Organelles of a Cell
A
Cell Wall Cell Membrane Cytoplasm Nucleus Ribosomes Mitochondria Golgi Bodies Endoplasmic Reticulum Vacuole Lysosomes Chloroplasts
9
Q
Atom
A
- atomic number, Z, is number of protons in nucleus and electrons in neutral atom
- mass number, A, protons + neutrons in nucleus
10
Q
Isotope
A
- are atoms of an element with same atomic number but different mass number
- number of protons +electrons the same
- difference in number of neutrons in nucleus
11
Q
radioisotopes
A
- radioactive atoms of element that spontaneously decay into smaller atoms, subatomic particles, and energy
- half life: time it takes for 1/2 of nuclei in radioactive sample to decay
- radioactive tracers: radioisotopes used to follow chemicals through chemical reactions and trace their path through cell/body
- -> EX. PET scans
- -> EX> I-131 to scan thyroid
12
Q
Chemical Bonding
A
- orbitals: volume of space around nucleus where electrons found
- intramolecular forces of attraction: covalent bond that holds atoms together and ionic bond that holds ions together in salt
13
Q
Acid and Base
A
- Acid: substances that increase the concentration of H3O+ when dissolved in water and contain at least 1 ionisable hydrogen atoms in their chemical structure
- base: substances that increase the concentration of OH ions in solution
14
Q
Elements of Life
A
CHNOPS
- Carbon (skeleton of molecules)
- Hydrogen (bonding, enzymes, stabilizer)
- Nitrogen (amino acids, DNA)
- Oxygen (energy by oxidising)
- Phosphorus (build/repair, phospholipids)
- Sulfur (comp. amino acid)
15
Q
Isomers
A
compounds with same formula but different 3D shapes 3 types: -->structural -->geometric -->opticals
16
Q
SImple Functional Groups
A
alkanes: single bond
alkenes: at least 1 double bond
alkynes: at least 1 triple bond
17
Q
CIS vs TRANS
A
α- glucose and β- glucose
18
Q
6 Functional Groups
A
Hydroxyl (+OH)
- -> makes molecules polar
- -> molecule water soluble
- -> alcohol: organic molecules with only hydroxyis
- ->found in sugars
Carbonyl (+CO)
- ->carbon+oxygen= double bond
- -> makes molecules polar
- ->water soluble
- ->aldehyde: when carbonyl added at end of chain
- -> ketone: carbonyl group added in middle
Carboxyl (+COOH)
- ->double bond to oxygen atom
- ->bonded to hydroxyl
- ->makes molecules polar
- ->water soluble
- ->carboxylic acids (more acidic)
- -> found in fatty acids
Amino (+NH2)
- ->in amino acids
- ->makes compounds basic
- -> makes molecules basic
- -> makes molecule water soluble
Sulfhydryl (+SH)
- ->thiols: similar to alcohol/phenol
- -> found in proteins
- ->form disulfide bridges (weaken peptide links)
Phosphate (+PO4)
- ->organic phosphates
- ->energy storage and transferring
- ->makes molecule polar
- -> makes molecule water soluble
- ->makes compound acidic
- -> in ATP
19
Q
Linkages
A
Ether:
- ->alcohol groups
- -> common in carbs
Ester:
- –>alcohol and carboxyl
- ->common in lipids
Peptide:
- ->amino and carboxyl
- ->common in proteins
Anhydride:
- ->2 carboxyl or 2 phosphate groups
- ->common in ADP/ATP
20
Q
Polymers
A
large molecules of subunits put together
21
Q
Monomer
A
subunit of polymer
22
Q
Hydrolysis
A
taking 2 monomers apart
hydro=water / lysis=break
monomer chain broken so H+ and OH- are added
23
Q
Dehydration
A
putting together
water molecule is removed from each monomer attachment
–>1 monomer loses H+, other loses OH-
–>forms covalent bond
24
Q
Define Nucleic Acids
A
informational macromolecules that stores hereditary info for structural and functional characteristics
25
DNA vs RNA
- both nucleotide polymers
- both sugars
DNA (deoxyribonucleic acid)
- double strand
- coil into helix
- strands held together by H bonds between nitrogenous base
- strands run antiparallel
- has free phosphate group at one end, free sugar at other end
RNA (ribonucleic acid)
- single strand
- coil into helix
26
Nucleotide Subunit
contain:
- nitrogenous base
- sugar (DNA or RNA)
- phosphate group
27
Nitrogenous Base
```
Adenine
Guanine
Cytosine
Thymine
Uracil
```
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Pyrimidines (CUT the PY)
Pyrimidines (single rings):
- Cytosine
- Uracil
- Thymine
29
Purines
purines (double rings):
- Adenine
- Guanine
30
Complementary Base Pairing
```
only certain nitrogenous bases can pair with certain nitrogenous bases
DNA:
--> A-T (with 2 H bonds)
--> G-C (with 3 H bonds)
RNA:
-->A-U
-->G-C
```
31
Define Protein
A protein is a molecule composed of polymers of amino acids joined together by peptide bonds.
32
Structure of Proteins
1: Primary Structure: as proteins begin forming, they start as a straight chain of amino acids
2. Secondary Structure: for the primary structure to become secondary, the original chain begins to twist and curl up. In the amino acid chain, each amino acid interacts with other and twists like a corkscrew (alpha helix) or folds into a sheet (beta sheet)
3. Tertiary Structure: the creation of protein begins with amino acid chains folding even more and bonding using bridges (disulfide bridges)
4. Quaternary Structure: several amino acid chains from the tertiary structure fold together into a “blob”
33
Define Carbohydrates
A macromolecule that is composed of carbon, hydrogen, and oxygen.
34
6 functions of Carbs
1. provide energy and regulate blood glucose
2. Sparing the use of proteins for energy.
3. Decompose fatty acids and prevent ketosis
4. Biological recognition
5. Flavour and sweeteners
6. Dietary Fibres
35
3 types of carbs
Monosaccharides,
Oligosaccharides,
Polysaccharides.
36
Monosaccharides
- most simple sugars
-composed of one chain of carbon atoms to which the hydroxyl groups attach.
EXAMPLES:
-->Glucose- an energy source for virtually all cells
-->Galactose- a component of lactose, milk sugar.
-->Fructose- fruit sugar
-They can also be used as foundations for more complex carbohydrates or components to amino acids.
37
Oligosaccharides
-Formed when two or three monosaccharides combine through dehydration synthesis.
EXAMPLES:
-->fructose
-->lactose
-->maltose
-provide energy to muscles, fuel for the CNS, and they prevent tissues from consuming protein for energy.
38
Polysaccharides
-Polymers that can composed of of hundreds-thousands of monosaccharide subunits.
-They can be in straight or branched chains.
FUNCTIONS:
-->energy storage (starch, glycogen)
-->Structural support (cellulose, chitin)
39
Define Lipids
molecules that contain hydrocarbons and make up the building blocks of the structure and function of living cells.
40
Unsaturated vs Saturated Fat
Unsaturated:
-If a hydrocarbon has any double carbon bonds it is considered a unsaturated fat. Unsaturated fats come primarily from plant foods, such as nuts and seeds, and are liquid at room temperature (oil), unsaturated fats do not raise cholesterol.
Saturated:
-Saturated fats are are hydrocarbons without any carbon bonds, these fatty acids are high in cholesterol and are solid at room temperature. Saturated fats are very common in meat products such as: fatty beef, lamb, and pork.
41
Chloro Lipids
- lipids with a carbohydrate attached by a glycosidic bond.
| - found on the outer surface of all eukaryotic cell membranes.
42
Steroids and Lipids
Steroids are lipids because they are hydrophobic and insoluble in water, but they do not resemble lipids since they have a structure composed of four fused rings
43
Waxes and Lipids
-A wax is a simple lipid which is an ester of a long-chain alcohol and a fatty acid.
44
Key Terms
```
ENERGY:
-ability to do work
METABOLISM:
-sum of all anabolic and catabolic processes in cell
KINETIC ENERGY:
-energy possessed by moving objects
POTENTIAL ENERGY:
-energy stored by objects at rest
WORK:
-transfer of energy from one place to another
```
45
Bond Energy
- Min energy required to break one mole of bonds between two species of atoms
- Also same as min energy required to form a bond or released when a bond is formed
- Measure of stability of chemical bond
46
Potential Energy Diagrams
Reactant-->(activation energy--> transition state--> products
ENDOTHERMIC:
-if products is higher than reactant
EXOTHERMIC:
-if products is lower than reactant
47
Entropy
-A measure of the randomness or disorder in a collection of objects or energy
48
Reversible Metabolic Process
- The reaction of metabolism are enzyme catalyzed (reach equilibrium)
- Most of the reaction of metabolism are a series of chain reaction
49
Enzymes
-Most enzymes are proteins
-Act as catalyst to accelerate reaction
NAMING:
-sucrASE
-lactASE
-maltASE
50
Structure of Enzyme
```
Active site
Allosteric Site
Substrate
Enzyme
Competitive Inhibitor
Noncompetitive Inhibitor
```
51
Models of Enzyme Function
Lock and Key:
-one key per lock
Induced Fit:
-assumes active site is more flexible
52
How do enzymes work
Weaken bonds which lower activation energy so reaction can be catalyzed
--> Weaker bonds means less activation energy needed in transition state of reaction
53
Enzyme Inhibitor
Competitive Inhibitor
Noncompetitive inhibitor
Irreversible
Reversible
54
Competitive Inhibitor
- similar to regular substrate, able to enter active site
- binding can stop substrate from entering active site and catalysing
- can be reversible
55
Noncompetitive Inhibitor
- doesn't compete for active site
- binds to allosteric site
- causes conformational changes to enzyme, preventing substrate bonding
56
Irreversible
-reacts with enzyme and changes chemically
| EX: toxin
57
Reversible
- bind noncovalently
| - can change back
58
Enzyme inhibitors vs activators
```
Inhibitors:
-decrease activity
-stabilizes inactive conformation
Activators:
- increase activity
-stabilizes conformation that enables reaction
```
59
Cofactors and Coenzymes
- Require non -protein cofactor to help carry out functions
| - Inorganic substance and vitamins are sometimes need
60
Environmental Condtions affecting enzymes
```
Extreme Temp:
-every enzyme has optimal temp where activity is best
pH:
-optimal pH ~6-8 pH
Ionic Concentration:
-don't like salt
-inorganic ions interfere with H and ionic bonding
(exception: algae in tidal pools)
```
61
Concentration of Substrate and Enzyme
- Rate of enzyme catalyzed reaction depends on concentrations of substrate AND enzyme
- As either concentration is increased that rate of reaction increases
- There will be Saturation point (max increase)
62
Feedback Inhitions
- Occur naturally and involved in regulation of metabolism
- product of 1 enzyme can be substrate for next enzyme
- eventually too much product, so product can act as noncompetitive inhibitor on first enzyme
63
Membrane
- "Fluid mosaic model"
- Mosaic of molecules and proteins (integral(can transport) and peripheral(outside proteins))
- Dynamic
- PARTS:
- ->Phospholipids
- ->Protein channels
- ->Protein cytoskeleton
- ->Cholesterol
64
Cellular Membrane
-envelopes the cell
-selectively permeable
-maintain homeostasis
TYPES:
-receptor proteins
-transport proteins
-marker proteins
65
Cell Transport
Passive Transport
| Active Transport
66
Passive Transport (no energy)
DIFFUSION:
-Molecules move from area of higher concentration to area of lower concentration
OSMOSIS:
-diffusion of water and solutes
-isotonic (concentration outside and inside equal)
-hypotonic (less solute and more water than in cell)
-hypertonic(more solute and less water than in cell)
FACILITATED DIFFUSION:
-involved from high concentration to low concentration
-some extra to help move
-->channel/carrier protein
67
Active Transport (ATP)
SODIUM POTASSIUM PUMP:
-Drives movement against concentration gradient
-Take sodium ions from inside cell and pumps out
-Pumps potassium into cell
ENDOCYTOSIS:
-molecules too large to diffuse through cell membrane
-taken into cell through vesicle formation
-phagocytosis (cell eating)
-pinocytosis (cell drinking)
-receptor mediated endocytosis (bind to specific nutrients)
EXOCYTOSIS:
-removes molecules through vesicle form
-vesicle fuses to membrane, discharges contents out of cell
