Exam 1(pre ME 1) Flashcards
How do electrons lose/gain energy?
They gain energy by moving away from the nucleus or to higher energy levels and lose energy by moving toward the nucleus or to lower energy levels
Covalent bond
Chains and functional groups, hardest to break(strongest) in aqueous(living) environments
Ionic bonds
Holds something together until something with a stronger affinity pull it apart
Hydrogen bonds
Weakest bonds in aqueous environments, but strong in larger numbers
Which interactions does signaling involve and why
Ionic and hydrogen bonds because covalent bonds are hardest to break/pass stuff on with
What attracts H20 and NH3+ ?
The slight positive charge in the Hydrogen in water attracts to the slight negative charge in the N in ammonia
In what case can H bonds disrupt ionic bonds?
They can disrupt ionic bonds when the higher number of H bonds making the total force of H bonds stronger than the total force of ionic bonds
What is the type of bond between H and O in H2O?
Polar covalent bonds(sharing electrons)
Properties of polar substances
Hydrophilic, can dissolve in water, electrons not shared equally, lots of branching
Properties of nonpolar substances
Hydrophobic, can not dissolve in water, planar/flat, little branching
Amphipathic+example
A substance with polar and nonpolar components
example: DNA
What allows earth to have liquid oceans?
Solid water is less dense than liquid water so it floats, keep the oceans from freezing
Which properties of water make it critical to life?
- Surface tension
- Cohesion/adhesion
- Support
- Dehydration/hydrolysis
Which part of the plants moves water up?
xylem
What allows the xylem to move water up a plant
cohesion/adhesion
How can water provide support?
Through pressure mechanisms like hydrostatic skeletons
What role do dehydration and hydrolysis reactions play
Dehydration reactions build macromolecules(make covalent bonds), hydrolysis breaks them down(break covalent bonds)
Example of hydrolysis
cellular respiration
What role does pH play in macromolecules of living things
pH affects structure, therefore affecting function. cells often manipulate function by changing pH
What makes carbon special?
It has 4 bonding sites and can bond to many different kinds of atoms
Hydroxyl groups
-OH
Essential in formation of DNA, RNA and proteins, very reactive
Carboxyl groups
-COOH
Essential in protein formation
Phosphate
-OPO3(2-)
Important in the structure of DNA/RNA
How do you change the function of molecules?
alter its shape/structure
Variety of proteins compared to DNA/RNA and why
proteins have more variety because they have more building blocks
Big four atoms and the next 2 most common atoms
big four: C, N, O and H
next 2 most common: P and S
What are carbohydrates made of?
C, H and O
compounds of C and H2O
What molecules do carbohydrates form?
Monosaccharides, dissacharides and polysaccharides
Glucose in aqueous environments
Will usually circularize
Monosaccharides
Have different numbers of carbons, simple sugars, ring or linear, glucose, ribose, deoxyribose
How many carbons are in the building blocks of DNA/RNA?
5
What sugar does DNA have and what makes it important
deoxyribose, it is missing a hydroxyl group
Why is glucose a preferred energy source for cells?
It is easier to break down
Glycosidic linkage
Covalent bond that our bodies metabolize easily
Dissacharides
2 monosaccharides, sucrose, lactose, maltose
Polysaccharides
have many different function, long term energy storage, glycogen, starch, cellulose, chitin, peptidoglycan
Starch
Polysaccharide used by plants for long term energy storage, monomers of glucose put together, low solubility, branching
Lipids
- nonpolar/hydrophobic
- long term energy storage
- fats, triglycerides, steroids and hormones
Carbon to carbon bond characteristics
Flat, planar, nonpolar, lacking O
Saturated vs Unsaturated fatty acids
Saturated: Carbon saturated with H, solid at room temp, can be packed together making it solid
Unsaturated: Kink/bend, more common in plants, carbon-carbon double bond, liquid at room temp, can not be packed together because of kinks making it liquid
Phospholids
- Amphipathic
- Crucial to membrane structure
- Circular polar heads, lobe shaped fatty acid tails
Glycerol backbone
3 carbon backbone: 2 hydrophobic, nonpolar fatty acids attached to 1 polar, hydrophilic phosphate head(amphipathic)
Steroids
- 4 fused rings
- critical signaling molecules
- control gene activities
- Nonpolar, planar
- Can interact with DNA by going into the cell nucleus to turn off genes
- Can diffuse across membranes
What are proteins known as?
The workhorse of the cell
What do proteins contain
- Big four elements(C, H, O, N)
- Some contain S in essential amino acids
- 20+ amino acid building blocks
Essential amino acids
amino not acids not made by the body that must be retrieved
Enzymes
- most are proteins
* end in -ase
Amino acid structure
Carbon bonded to an amino group, a carboxyl group, H, and a side chain R group
Sources of diversity in amino acids/proteins
- Different R groups in every acid
* more than 20 amino acid building blocks
What role does polarity play in protein structure?
Nonpolar groups end up pointing inside of the protein as it folds, polar groups point outside
Peptide bonds
- How amino acids connect
- C and N on the end of amino acids hook together to form chains which or called peptide bonds
- formed through dehydration synthesis
Polypeptide
- linear chain of 4 or more amino acids
* Amino acids makeup the front end, a carboxyl group makes up the back end
Primary structure
- 1st hierarchal level of protein structure
- determine by gene sequence
- Order of amino acids
Secondary structure
- 2nd hierarchal level of protein structure
- Repeating patterns that are determined by chemical and physical properties of amino acids(primary structure)
- made of of alpha spiral helixes and folded beta pleated sheats held in place by hydrogen bonds
- refers local interaction if R groups
- Affects atoms that are close to each other
Tertiary structure
•3rd hierarchal level of protein structure
•Complex 3D shapes
Proteins fold back and forth on themselves
•Allows portions of protein at long distances to interact
Quaternary structure
- 4th hierarchal level of protein structure
- Interactions of multiple polypeptides
- Note all proteins have this level of structure
5 factors promoting protein folding and stability
- H bonds
- Ionic bonds
- Hydrophobic effects
- Van der Waals forces (attractive forces)
- Disulfide bridges
Disulfide bridges
Covalent bonds between 2 sulfurs and R groups
How are DNA/RNA related to nucleic acid?
they are polymers of nucleic acid
Building blocks of DNA and RNA
Both: 5 carbon sugar attached to a sugar-phosphate backbone group and nitrogenous base
DNA bases: GATC
RNA bases: GUAC
DNA and RNA function
DNA: Store genetic info
RNA: critical in info expressions, has many types, can do work, functions are still being learned about
What holds nucleic acids together?
H bonds
Nucleic acid structure, which type of molecule do they structurally resemble?
Planar, flat, stacked, nonpolar, like steroids
DNA structure
- Antiparallel 5’ and 3’ ends that are complementary to base pairs
- has long ribbons of covalent linkages between sugar and phosphate
- Inside is stable, outer part has lots of negatively charged phosphates
RNA structure
- Single stranded
- 5’ and 3’ ends
- can be 3D and complex
- complementary to nucleic acids
- secondary structure
- has a ribbon like, negatively charged sugar phosphatebackbone
How does diversity of nucleic acids and proteins compare
Nucleic acids can be diverse but not like proteins
Effects of cholesterol on membrane
In warm temps: cholesterol stabilizes the membrane and makes it less fluid
In cold temps: makes membranes more fluid, acts as antifreeze
Present in all cell membranes
What does fluidity of the membrane depend on?
- Length of FA chains: Shorter FA chains=more fluid and vice versa
- Degree of saturation: More saturated=less fluid
- Cholesterol
What do all cells have?
- Cell membrane
- Cytoplasm/cytosol
- Ribosomes
- DNA-based genome
- ATP for energy
Ribosomes
make proteins and replenish proteins who have fallen into disrepair
Glycoprotein
Proteins in cell membrane that has polar sugars attached to it with positive and negative charges(water friendly) to keep the cell hydrated. Recognizes other cells
Endoplasmic reticulum
(ER) Conducts protein synthesis
Split into rough and smooth ER
Rough: protein synthesis
Smooth: lipid synthesis
Golgi
Packing and transport within cell, stacks of membrane
Endomembrane system
present ONLY in eukaryotes, used to move stuff around
Molecules with high, moderate, low and very low permeabilities
High: Gases, small and uncharged polar molecules
Moderate: Water, urea
Low: Organic polar molecules
Very low: ions, charged polar molecules, macromolecules
Hypotonic vs hypertonic
Hypotonic: less concentrated
Hypertonic: more concentrated
Membrane protein functions
- transport
- enzymatic activity
- Signal transduction
- Cell-cell recognition
- intercellular joining
- Attachment to cytoskeleton and extracellular matrix
nucleolus
inside nucleus, transcribed and assembles ribsomes
Which part of the ER is close to the nucleus?
Rough ER
Atoms that make up carbs, lipids and proteins
Carbs: C, H, or O
Proteins: C, H, O, N
Lipids: C, H, O
