Biological Concept Introduction & Cells Flashcards
Chapter 1
Biology is the study of what?
Living Things
What is an atom?
The smallest unit of an element that retains all the properties of the element.
What is a molecule?
2 or more atoms linked together
What is the term for anything the occupies space and mass?
Matter
A positive ion is called a ?
Cation
A negative ion is called a ?
Anion
An isotope has the same atomic # but different what 2 things
Different masses and number of neutrons
H2O is the universal solvent meaning it can ..
-H bond with itself
-has high boiling point
-has high melting point
What is the structure of H2O
A bent molecule at 105 degrees, polar molecule can form 4 Hydrogen bonds
If a molecule shares electrons equally its called a
nonpolar covalent bond
If electrons are shared unequally its called a
polar bond
How do enzymes increase the rate of a biological reaction?
By lowering the energy of activation for forward and reverse reactions
Delta G: Free Energy represents
the energy available to do work
+Delta G is
non-spontaneous
-Delta G is
spontaneous
What does a spontaneous reaction mean?
The reaction goes to completion (to the right) by over 50%
Delta G =0 at equilibrium
Delta H: Enthalpy
Heat
*almost all exothermic (heat-releasing) processes are spontaneous
Delta S: Entropy
the amount of randomness or disorder in a system
pH=
-log[H30+]
pOH=
-log[OH-]
Acids will donate what?
H+ ions
Bases will accept what?
H+ ions
A large Ka =
a small pKa, means its a strong acid
pKa=
-logKa
What is a buffer?
a compound that resists pH change
*a weak acid or base and its salt
To solve buffer questions use the Henderson-Hasselbach Equation
pH=pKa+ log [base]/[acid]
Energy can be put into 2 categories
1.) Kinetic: energy of motion (blood flow)
2.) Potential: energy that is stored (glycogen)
Temperature is a measure of what?
Average kinetic energy
1st Law of Thermodynamics:
energy can neither be created nor destroyed but only transferred or changed from one form to another
2nd Law of Thermodynamics:
The entropy (disorder) of the universe is increasing over time
-all processes involve heat loss, with no process being 100% efficient
3rd Law of Thermodynamics
As the temperature approaches absolute zero (-273C or 0K), the entropy of a system is minimum
What is heat?
The transfer of thermal energy between 2 bodies
What is the direction heat travels?
From hot object to cold object
What is an open system?
Mass and energy can exchange
ex: H2O in an open container
What is a closed system?
Allows energy to transfer, but not mass
ex: H2O in a closed flask
What is an isolated system?
Neither energy nor mass can transfer
ex: H2O in a flask is closed and placed in a vacuum jacket
What is an exothermic reaction?
It gives off heat so the surroundings get hot
What is an endothermic reaction?
It absorbs heat so the surroundings get cold
Solid to Liquid
Melting delta H is +
Liquid to Solid
Freezing delta H is -
Liquid to Gas
Vaporization (boiling) delta H is +
Gas to Liquid
Condensing delta H is -
Solid to Gas
Sublimation delta H is +
Gas to Solid
Deposition delta H is -
What does ATP drive?
Endergonic reactions to become exergonic
What is catabolism?
Degradative free-energy yielding reactions
What is anabolism?
Other enzyme-catalyzed pathways that start from precursor molecules and convert them into larger and more complex acids
*pathways require energy input
ATP is the crosslink between what 2 pathways?
catabolic and anabolic
The body maintains the concentration of ATP in a steady state… how?
The body makes ATP and breaks it down as it is needed to maintain homeostasis
What are Chemotrophs?
A class of organisms that derive free energy from the oxidation of fuel molecules
What are the 2 major electron carriers?
NADH and FADH2
What molecule goes into the TCA Cycle?
Acetyl CoA
What are others names for carbohydrates?
sugars and starches
If you are at a chiral carbon and the OH is on the right it has what kind of configuration?
R
If you are at a chiral carbon and the OH is on the left it has what kind of configuration?
S
Alpha and beta sugar represent diastereomers called what?
Anomers
How many sugars do Oligosaccharides have?
4-10
How many sugars do Polysaccharides have?
Usually over 10
How are disaccharides made?
By the linking of monosaccharides in a process called dehydration synthesis
What is chitin?
A derivative of glucose
A component of cell walls in fungi and part of the exoskeleton of arthropods, such as crustaceans (lobsters, crabs, shrimp) as well as insects
How are sugars formed?
Dehydration Synthesis
How is sucrose formed?
By a 1,2-linkage between glucose and fructose
What is cellulose and why is it important?
A linear polymer of glucose with B 1,4 glycosidic linkages
*we as humans lack the enzyme required to break this linkage
*cellulose is the most abundant component in the biosphere!!!!
What is amylose?
A linear polymer of glucose composed of Alpha 1,4 glycosidic linkages
*most starch from plants is 20% amylose
What is amylopectin?
A branched polymer of glucose, alpha 1,4 linkages
*most starch in plants is 80% amylopectin
What is glycogen?
animal starch
What is glucose stored as and where is it stored?
It is stored as glycogen and is found mainly in the liver and skeletal muscles
*glycogen is very large branched molecule
Excess lipids are stored as what?
Fat
What are 4 facts about lipids?
- They are used for energy
- Components of nerve cells
- Used for protection
- Membrane components
What are waxes?
Esters of fatty acids and of long-chain alcohols
Saturated fats are what at room temperature?
Solid
Unsaturated fats are what at room temperature?
Oils
Which lipids has the lowest melting point and why?
Unsaturated fats - have one more double bonds between carbons putting a “kink” into the molecule preventing it from packing tightly
*lowers the interactions of Van Der Waals so unsaturation increases as does the fluidity!!!
How do we maintain flexibility and prevent a membrane from becoming rigid? Where is this seen?
We increase the percentage of unsaturated fats in the membrane!
This is seen in fish and other cold-blooded animals that need to adapt to colder temperatures
If it gets too hot what gets increased saturated or unsaturated fatty acids?
saturated fatty acids
If it gets too cold what gets increased
percentage of unsaturated fatty acids
What is the design of steroids?
It has 3 six-membered rings and 1 five-membered ring
Prostaglandins are derived from what acid
Arachidonic acid
Prostaglandins make up what?
Things such as estrogen, cholesterol, progesterone, and testosterone
What is cholesterol?
an unsaturated steroid alcohol which makes up a large part of membranes. It works locally with nearby cells and works together with hormones
What can prostaglandins like cholesterol do in some organs?
- help regulate blood flow
- effect nerve transmission
If you radio-label a S atom, it is likely to end up in a what?
Protein!!! They contain C,H,N,O,S
Proteins are made up of individual units called what?
Amino Acids
Some amino acids are H2O soluble this means that they are ?
Hydrophillic (water loving)
Some amino acids are H2O insoluble this means they are?
Hydrophobic (water fearing)
Essential amino acids must be obtained from what?
The diet
Amino acids exist as salts allowing them to have what kind of melting points?
High melting points and making them water soluble
In a highly acidic environment we see what?
NH3+ and COOH
In a highly basic environment we see what?
NH2 and COO-
Amino acids can link together for what kind of bond as water is removed?
Peptide bond
In a protein several attractive forces or bonds can be found:
Hydrogen bonding, salt bridge, disulfide linkage, hydrophobic interacgtions
If a peptide had six amino acids we have how many peptide bonds?
five
The primary protein structure consists of what?
sequence of amino acids, held by covalent bonds including the disulfide bond
The secondary structure of proteins consist of what?
the 3D configuration of localized regions (helix of B-pleated sheet held together by hydrogen bonds)
The tertiary structure of proteins consists of what?
The 3D shape of the whole moelcule held by H bonding, disulfide bonds, salt bridges (electrostatic interactions) and Van der Waals (hydrophobic interactions)
What is the quartenary structure of proteins?
1 polypeptide chain interacting with another the same 4 attractions present in tertiary are also present here
What happens during the digestion of proteins?
the breakdown of the amide or peptide bond of the protein so the primary structure is lost
What happens during the denaturation of proteins?
The primary structure remains the same but the 2,3 and 4th structures are lost
What are some possible denaturing agents?
Heat, radiation, detergents, strong acids/bases, salts of heavy metals, urea
Nucleic acids are polymers, what are the monomers of nucleic acids called?
nucleotides
What 3 things make up a nucleotide?
- sugar
- phosphate
- Nitrogen base
Purines consist of what nitrogenous bases?
Adenine and Guanine they have 2 rings
Pyrimidines consists of what nitrogenous bases?
Cytosine, Uracil and thymine they have 1 ring
What is a nucleoside?
A sugar and nitrogenous base
What forms the structural framework of DNA and RNA?
The sugar-phosphate “backbone”
What is a phosphodiester link and where is it found?
It is a connection between successive monomer units in nucleic acids
It is between the 3’ OH group of one sugar and the 5’ OH of another sugar
What is the protoplasm?
The living substance of the cell it includes the
1. cytoplasm: involves the contents of the cell excluding the nucleus
2. karyoplasm: simply forms the contents of the nucleus
What separates the cytoplasm from its extracellular environment?
The plasma membrane (plasmalemma)
What is the cytoplasm mainly composed of?
It is mainly H2O and various organic and inorganic substances that are dissolved or even suspended
What is the fluid suspension of the cytoplasm called?
cytosol
The phospholipid molecule of the lipid bilayer is made up of a what?
Polar head group and 2 long nonpolar fatty acyl tails
Lipids and many membrane proteins are in what kind of motion?
constant lateral motion
What is e
