BI 253 Ch 4&5 WTF
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What is a glycosidic linkage?
Covalent bond formed by condensation reactions joining monosaccharides
What are the 4 main types of glycosidic linkages?
What are 2 most common disaccharides w/their linkage types?
- Sucrose α-1,2
- Lactose β-1,4
Humans can break down maltose but not cellobiose b/c. . . .
Shape differences causing changes in biological nature
What are oligosaccharides?
Chain of 3-20 monosaccharides
What are polysaccharides?
Giant chains of monosaccharides connected by glycosidic linkages
Polysaccharides are primarily used for ___ & ___ in the body.
Storage & structural support
Starch & glycogen are made up of what?
Repeating monomers of glucose
Galactosamine is a major component of ___.
Glucosamine is a component of ___ & found where?
Chitin in skeletons of insects, prawns, crabs & cell walls of fungi
What makes lipids hydrophobic?
Non polar covalent bonds between hydrogen & carbon
What causes lipids to want to stick to each other?
Van der Waals forces
Lipids in cell membrane structure are known as ____.
Carotinoids are lipids that do what?
Capture light energy in the eyes
The polymer triglyceride is composed of what?
4 monomers - 3 fatty acids & 1 glycerol molecule
What bonds are used to link lipid molecules together?
Ester Linkages formed by condensation reactions
What comprises a fatty acid?
Long chain of hydrocarbons w/carboxyl grp at one end
When speaking of a saturated fat; what does saturated mean?
It means the hydrocarbon chain in saturated w/hydrogen
T or F. . Animal fats & tropical plant oils are saturated?
What tells us that a fatty acid is unsaturated?
- At least 1 double bonded carbon causing bends in the chain
- Liquid at rm temp
How are hydrogenated oils created?
By adding hydrogen to unsaturated fats.
What is the structure of a phospholipid?
- 2 hydrophobic fatty acid tails
- 1 hydrophilic phosphate attached to the glycerol
In an aqueous environment, how are phospholipids oriented & what do they form?
- Phosphate heads face outward & fatty acid tails inward (tail to tail)
- Cell membranes
What is β-carotene used for in plants? In animals?
- Trap light in photosynthesis
- 2 identical pieces of vitamin A required for vision
What is the mother structure for steroid hormones?
What vitamins are fat soluble?
A,D,E & K
Define Nucleic Acids.
Polymers specialized for storage, transmission & use of genetic info
What is the monomer of a nucleic acid?
What are the 3 components of nucleotide?
- Pentose Sugar
- Phosphate grp
- Nitrogen containing base
What are the 2 sugars that could be in a nucleotide?
What is the difference between ribose & deoxyribose?
An O molecule at Carbon #2
Waxes protect against ___ in ___, ___ & ___ ___.
- Hair, feathers, insect eggs
What is vitamin A mad fr & used for?
- Norm development, Maintenance of cells & night vision
Vitamin D is made in the ___ fr exposure to ____.
Vitamin D does what?
Aids absorption of Ca & important for bone health
Vitamin E is a good ___.
Vitamin K is important for ___ ___.
Nitrogenous bases can be either ___ or ___ in structure.
- Pyrimidine - single ring structure
- Purine - fused double ring structure
Covalent bonds between nucleotides are called ___ ___.
Describe the phosphodiester linkage.
Phosphate grp bonds to #3 C of 1 pentose & #5 C of another
RNA molecules consist of what?
- Single strand of nucleotides
- Unpaired bases
DNA is a ___ ___ of nucleotides.
The double stranded DNA is antiparallel which means?
One strand ends w/free C 5' of deoxyribose & other ends w/ C 3' of deoxyribose
What are the 4 bases found in DNA?
- Adenine (A) purine
- Guanine (G) purine
- Thymine (T) pyrimidines
- Cytosine (C) pyrimidines
What are the 4 main types of Biomolecules (macromolecules)?
- Nucleic Acids
What are some roles of lipids (2)?
- Energy Storage
- Structural support
What are some roles of proteins (8)?
- Structural support (collagen)
- Catalysis (enzymes)
- Transport (hemoglobin)
- Protection & defense (Antibodies/keritin)
- Regulation of metabolic activities
- Maintenance of Homeostasis
- Info Storage
- Means for mvmt, growth & development
What are 2 roles of carbohydrates?
- Energy Storage (glycogen)
- Mvmt, growth & development
What are polymers?
Long chains of monomers linked together by covalent bonds
___, ___ & ___ are considered lg molecules.
Proteins, Polysaccharides & Nucleic acids
What 6 elements compose monomers?
C, H, O, N, P, S
___ & ___ make up skeletons & then special grps of atoms attach in specific places.
Carbons & Hydrogens
What are functional groups?
Special grps of atoms w/specific chem properties that attach to a larger molecule
An isomer is what?
- Molecule w/same chem formula but atoms arranged differently
- ie glucose & fructose
Explain structural Isomers.
Isomers that differ in how their atoms are joined together or bonding arrangement
Explain geometric Isomers.
Isomers that differ in the placement of their functional grps or atoms around a double bond
Each functional grp has a ___ ___ ___ which it confers to the larger molecule.
Specific Chem Property
Optical or stereoisomers occur when . . . .
An α-carbon has 4 different functional grps attached to it & 2 resulting molecules are mirror images of each other.
What does a condensation or dehydration reaction do?
Builds polymers fr monomers by covalently bonding OH grp of 1 to a H of another w/release of a molecule of H₂O
What 2 things are required for a condensation reaction?
Energy & special enzymes
What does a hydrolysis reaction accomplish?
Breaks covalently bonded polymers into monomers w/the addition of H₂O
What are 3 characteristics of hydrolysis reactions?
- H₂O reacts w/covalent bonds linking polymers together
- Energy is released
- Performed by enzymes
What is the monomer or building block in a protein?
Explain a peptide bond?
Covalent bond between amino acids formed by a condensation reaction between a carboxyl grp & amino grp of another resulting in a polypeptide.
What is a polypeptide?
Single chain of amino acids held together by peptide bonds
What are the 3 parts of an amino acid structure?
- Amino Grp - N containing portion
- Acid - Carboxyl Grp
- R-Grp - Functional grp attached to α-carbon
Explain the R-Group.
- Functional Group attached to α-carbon
- Makes 1 type of amino acid different fr another
Explain a Zwitterion.
- At pH of 7, both amino & carboxyl group are ionized
- Carboxyl grp lost an H ion & amino grp has gained 1
Explain why we have D-amino acids & L-amino acids.
B/c α-carbon has 4 different functional grps attached to it we can get 2 isomeric forms that are mirror images. One is D-form & other is L-form.
What is the exception to the α-carbon rule & why?
Glycine b/c it has a H in its R group
If we shine light at a D-amino acid what happens & what does D stand for?
- Light will rotate clockwise
- D means dexterrotatory
If we shine light at an L amino acid what happens & what does L stand for?
- Light will rotate counterclockwise
- L stands for levorotatory
Only ___ ___ are commonly found in the proteins of most organisms.
What are the 3 primary classifications of amino acids?
- Charged R-Grps
- Polar w/o a charge
- Non-polar hydrophobic
What are the 3 special cases of amino acids?
The 1st amino acid of a peptide is called the what?
- N-terminus amino acid
- Free amino grp
The last amino acid of a peptide is called the ___ ___ ___.
- C-terminus amino acid
- Free carboxyl grp
What are the 4 levels of protein structure?
The primary structure of a protein is its ___ ___ ___.
Amino acid sequence
The secondary structure of a protein requires ___ ___.
What are the 2 common secondary structures?
- α helix - single poly peptide chain
- β pleated sheet - single or multiple polypeptide chains
Explain α helix structure.
Right handed coil w/spiral shape being caused by H bonds between slightly pos H & slightly neg O
What could prevent the creation of the α helix structure?
Large R groups
Explain a β sheet.
Sheet like structure stabilized by H bonds between regions of a peptide
Explain Parallel β sheets.
- Sheets where strings of peptides are aligned all the same way.
- Carboxyl grps on 1 end & amino grps on the other
Explain Antiparallel β sheets.
- Sheets where strings of peptides are aligned in an alternating pattern.
- 1st string starts w/carboxyl grp then 2nd starts w/amino & so forth
How is the tertiary structure of a protein formed & what determines its shape?
- By bending & folding secondary structures
- Determined by interaction between R groups
How can R groups interact in tertiary structures?
- Form disulfide bridges
- Hydrogen bonding
- Van der Waals forces
- Salt bridges
- Hydrophobic Interactions
What are salt bridges?
Ionic interactions between pos & neg charges deep in protein
What is a quaternary structure?
- Subunits of tertiary structures coming together to form final protein.
- ie hemoglobin
What are chaperonins?
Specialized proteins that keep other proteins fr interacting inappropriately w/one another prior to positioning
When proteins misfold what could happen?
They don't interact properly w/the environment & build up. The body tries to get rid of them & creates more problems in so doing
What are some reasons for protein specificity (5)?
- Cells can attach together by protruding proteins
- Enzymes need certain shapes to bind correctly
- Carrier proteins allow substances to enter cell
- Chem signals (ie hormones) bind to proteins on cell surface
- Antibodies recognize virus shape & bind to it
What is denaturation?
- Loss of protein's normal 3-D structure
- Only primary structure remains intact
- Can be reversible or irreversibl
- ie cooking an egg
What can cause denaturation?
- Changes in temp or pH
- High concentrations of polar substances
T or F: Some proteins can resist denaturation & be boiled for days bt once they cool they retain their reg activity
What's are 2 proteins that resist denaturation/
What is the issue w/proteins that resist denaturation?
- They remain present even when we think they have been eliminated.
- ie on surgical instruments
What does a carbohydrate contain?
Carbon molecules w/hydrogen & hydroxyl groups
How do carbs act as energy storage molecules in plants? In animals?
- Plants produce & store as sugar & starches
- Animals store as glycogen
What are the 4 major categories of carbohydrates?
What is the general formula for a carb monomer & in what ratio?
What is the most common monosaccharide & its formula?
When bonding monosaccharides what must we remember?
- H₂O is released therefore it comes out of the disaccharide
- C₆H₁₂O₆ + C₆H₁₂O₆ --> C₁₂H₂₂O₁₁ + H₂O
Like proteins, monosaccharides are also stereoisomers. Which series (d or L) are most common?
Isomers of glucose are known as ___ & come in what forms?
- β-glucose or α-glucose
What distinguishes α-glucose fr β-glucose?
α-glucose has H on top @ C#1; β it is on bottom
A hexose is a ___ ___ sugar.
A 5 carbon sugar is called ___ & found in ____.
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