Biology- Lipids and proteins

why are lipids not considered polymers 

they are not made up of repeating units of monomers 

what are the elements found in lipids

• hydrogen

• carbon

• little to no oxygen 

what are the roles of lipids in the body

• long term energy

• protection/insulation

• respiration- drives production of ATP

why are lipids not the primary source of energy in the body

they have a much slower breakdown and they can only be aerobically broken down

what are two differences and one similaity between fats and oils

1. fats are solid at room temp while oils are liquid

2. fats are generally from animal sources while oils are generally from plant similarity: They both contain fatty acids and glycerol and are combined by ester bonds

describe the structure of fatty acids 

they are made up of hydrocarbon chains with a carboxyl group at the end

how can fatty acids vary

depending on chain length or whether they are saturated or unsaturated

explain the melting point of saturated and unsaturated fatty acids

• saturated fatty acids have a high melting point because the chains are straight and closely packed 

• unsaturated fatty acids have kinks in them and are generally liquid at room temp

describe the formation of a triglyercide

1. condensation reaction called esterfication occurs between one glycerol molecule and three fatty acids

2. The -H from the glycerol and the OH- from the fatty acids are removed to remove 3 water molecules

3. this forms 3 ester bonds

what is the formula of a glycerol molecules

C₃H₈O₃

What do proteins make up in the body that make them vital

1. hair

2. nails

3. skin

4. antibodies

5. hormones

6. haemoglobin

7. allow our muscles to contract

8. tissues

how are genes involved in the production of proteins

genes are sequences of bases on a DNA molecule that determine the sequence of amino acids

what are the elements found in a protein

1. hydrogen

2. carbon

3. oxygen 

4. nitrogen 

5. sometimes sulfur 

describe the primary structure of a protein

just a sequence of amino acids joined together by peptide bonds (making a polypeptide chain). It is joined by a condensation reaction between the amino group of one amino acid and the carboxyl group of another 

describe the structure of an amino acid 

1. amino group (NH₂)

2. middle carbon atom 

3. R group attached to middle carbon atom 

4. Carboxyl group (COOH)

describe the formation of a peptide bond

a condensation reaction occurs between two amino acids in which the OH from the carboxyl group of one aa binds with the H of the amino group of another aa to release a water molecule and leave behind a peptide bond 

Why are R groups important

they determine the bonds and interactions once amino acids are linked 

• ionic bonds 

• disulfide bridges 

They also determine the tertiary structure of a protein because non-polar R groups are found as clusters inside the protein while polar, hydrophillic R groups are located on the outside 

what type of bond are peptide bonds

covalent

finish this equation

amino acid + amino acid =?

dipeptide + water 

How and in what structures are hydrogen bonds formed?

1. Secondary and tertiary structures 

2. between the slightly negative oxygen of the carboxyl group and the slightly postive hydrogen of the amino group 

3. can form between two amino acids that are close enough

describe the strength of hydrogen bonds and what this allows them to do 

generally weak (collectively strong) 

allows them to break and easily reform during changes of temp or pH 

hair straightening example 

How and in what structures are ionic bonds formed?

tertiary structures

between strongly negative and strongly postive R groups

what is the role of ionic bonds

found within proteins, help stabilise structure, stronger than H bonds but less common

How and in what structures are disulfide (bridges) bonds formed?

tertiary structures (VIB very important bond)

between two close enough cysteine amino acids in which during an oxidisation reaction hydrogen is removed from the SH groups allowing the sulfur to bond S-S covalent bonds

what makes disulfide bonds different from hydrogen bonds

changes are permamnent

perming- until cut off

what determines the order and number of amino acids in a polypeptide chain?

genes, made of DNA 

what are the four DNA bases 

ATCG

why is the primary structure of a protein very important 

one change in the polypeptide chain can impact the function of the entire protein

define the secondary structure of a protein

the folding of a polypeptide chain locally, across short regions using hydrogen bonds

describe the two main types of the secondary structure proteins

1. alpha helix- h bonds between turns

2. beta pleated sheets- h bonds within each sheet

define the teritary structure of a protein

the overall 3D shape of the entire polypeptide chain caused by interactions between R groups (hydrogen, ionic, disulfide)

where are hydrogen bonds formed in the teriatry structure of a protein

specifically found in polar areas of the R groups 

where are  disulfide bonds formed in the teriatry structure of a protein

R groups of cystein in the same polypeptide chains or an adjacent polypeptide chain (same chain though!!)

define the quaternary structure of a protein

consisting of more than one polypeptide chains

what are examples of why shape is vital for proteins

enzymes, antibodies 

what are fiborous proteins

structural proteins

describe the structure of fiborous proteins 

regular, repitive 

long parrallel chains (little to no tertiary structure)

occasional cross linkages that turn them into fibres

what are features of fiborous proteins that make them useful for their functions

they are insoluble

very tough

what are examples of fibourous proteins and structure

• keratin 

• collogen (a triple helix structure- 3 polypeptide chains)

what are globular proteins

functional proteins

describe the structure of globular proteins

complex teritiary and quaternary structures, compact and sphereical 

what is denaturation and causes for it 

the unfolding of a protein due to: 

• high temps

• extreme pH

• chemicals 

what are examples of globular proteins

• haemoglobin

• enzymes 

• antibodies 

• some hormones

explain the soluibility of globular proteins

hydrophillic r groups found on the outside making them mostly soluble in water or form colloids because they cannot be easily seperated

what is the test for proteins

bieruet solution, naoh, cuso4 = purple if proteins are present 

what is a conjugated protein

proteins that are chemically bonded to a non-protein molecule called a prosthetic group 

describe the structure and function of glycoproteins

• protein + carbohydrates 

• carbohydrates hold alot of water making it harder for it to be broken down by proteases. it also makes it slippery and viscous

• cell recognition

• cell signalling 

• mucus

• synovial fluid in joints 

describe the structure and function of haemoglobin

protein + iron

• oxygen transport 

• one haem group transports one oxygen molecule 

describe the structure and funtion of lipoproteins

• lipid + protein

• transports cholesterol in blood (lipid molecule combines with the lipid cholesterol)

• found in blood as LDL (more lipid less protein) 

• or HDL (less lipid more protein)

describe the role of unsaturated and saturated fatty acids with cholesterol 

• unsaturated raises HDL which takes cholesterol away from arteries (good)

• saturated raises LDL (bad)

what are the different ways proteins can be broken down

• denaturation

• enzymes (proteases)

• hydrolysis (breaking peptide bonds)