Biomolecules Flashcards
What are carbohydrates?
large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body.
What are the simplest carbohydrates and give examples
Monosaccharides (glucose, fructose)
What are biomolecules?
Chemicals made inside a living thing
What is the main element in biomolecules?
Carbon
What are the four major types of biomolecules?
Carbohydrates, Lipids, Nucleic Acids and Proteins
What elements make up carbohydrates?
Carbon, hydrogen, Oxygen
What are monosaccharides?
Consist of one single sugar unit and are the smallest units of carbohydrates
What is glucose and where is it found
An example of a monosaccharide, Organisms get their energy, found in fruit sweets, chocolate and in plants it’s made during photosynthesis
What is fructose?
Sweeter than glucose + found in fruit
What makes carbohydrates water soluble?
Hydroxyl Groups
What do carbohydrates usually occur as and give examples
polymers: polysaccharides, eg: starch, cellulose
glycogen (animal starch)
What is the most important carbohydrate?
Glucose, occurs all over nature because every organism has glucose
What are the functions of carbohydrates?
1) Energy, burn glucose to energy (ATP) which is needed for functions to occur in body
2) Structural carbohydrates -> Skin (Keratin + Dermatan sulfate), Joints (Chondroitin + Chondroitin sulfate). Have arthritis, chrondroitin sulfate gets broken down
Which is the most abundant organic compound on earth?
Cellulose
Glucose structure
H - C = O
H- C -OH
HO-C-H
H-C-OH
H-C-OH
H-C-OH
HWhat 6 common elements are found in food?
Oxygen, Hydrogen, Carbon, Nitrogen, Sulphur and Phosphorus
What four elements make up over 99% of the mass and atoms present in organisms?
Carbon, Hydrogen, Oxygen and Nitrogen
What are the five elements present in dissolved salts?
Sodium, Chlorine, Magnesium, Calcium, Potassium
What is a disaccharide and give examples
Two monosaccharides joined together, Sucrose, Maltose, Lactose
What is sucrose?
Glucose and fructose [table sugar]
What is maltose?
glucose + glucose molecules [barley]
What is lactose?
Glucose and galactose [milk]
What are polysaccharides?
Many monosaccharides linked together
Insoluble or only slightly soluble
What is starch and give sources
Polysaccharide Carbohydrate stored by plants. Long chains of glucose molecules and is easily digested bc glucose molecules are arranged in line eg, Rice, potatoes, flour, bread and pasta
What is cellulose and give sources
A structural carbohydrate in plants. Consists of long chains of glucose molecule cross bonding between chains, eg Paper and cotton
Due to the bonding of cellulose, what features does it have
More difficult to break down [digest] than starch which is why it is used as a fibre in diet. Fibre stimulates peristalsis
Very strong, used in cell walls of plants
What is glycogen?
It’s a carbohydrate stored by animals. Made of many glucose molecules more branched. Mostly stored in liver and muscles
What are the elements present in lipids?
Carbon, hydrogen and oxygen
What are fats?
Lipids that are solid at room temperature
What are oils?
Lipids that are liquid at room temperature
What happens when you’re hungry involving glycogen
glycogen releases glucose into the blood stream (mainly when your hungry)
What is chitin?
building block for nails (or in animals – hooves). All it is, is modified glucose
How are insoluble carbohydrates formed?
Modify glucose – replace hydroxyl to make it insoluble and make polymer of it, makes hardest substance in biology
What are the three types of lipids?
Glycerides
Phospholipids
Steroids
Are lipids water soluble?
No, Lipids are nonpolar molecules, which means their ends are not charged. Because they are nonpolar and water is polar, lipids are not soluble in water.
What are fatty acids?
Long hydrocarbon chains and end in carboxyl group
What are the four different types of fatty acids?
polyunsaturated, monounsaturated, saturated, and trans
What are the differences between the fatty acids
The basic difference between each of these is the number of carbon atoms with or without two hydrogen atoms bonded to them. (double bond etc)
What are saturated fatty acids?
In a saturated fatty acid, each carbon atom has the maximum amount of hydrogens it can have. In other words, it’s “saturated” with hydrogen (single bonds). This saturation makes the fatty acid very stable, which means it can withstand more heat before it becomes rancid.
Give examples of saturated fatty acids
Common examples of saturated fats are butter and coconut oil.
How do you physically know if a fatty acid is saturated?
An easy way to know if a fat is saturated is if it’s solid at room temperature.
Give an application of saturated fatty acids
Saturated fats are ideal for cooking because of their natural ability to withstand heat without being damaged.
What are Monounsaturated fatty acids?
In a monounsaturated fatty acid, one pair of carbon atoms forms a double bond with each other that replaces the bond each would have with one hydrogen atom. So it is unsaturated, but only by one bond.
Give an example of a monounsaturated fatty acids
The classic example of monounsaturated fat is olive oil. The oil in almonds, hazelnuts, and avocados is also monounsaturated.
How do physically know if a fatty acid is monounsaturated?
Monounsaturated fats are liquid at room temperature, but they solidify in the refrigerator.
Give examples of foods high in monounsaturated fats
include plant-based liquid oils such as:
olive oil,
canola oil,
peanut oil,
What are Polyunsaturated fatty acids?
A polyunsaturated fatty acid has two or more carbon pairs that have bonded together rather than with a hydrogen atom. This means the fatty acid is quite unstable.
Give examples of polyunsaturated fats
include most vegetable oils, most seed oils, soybean oil, flaxseed oil, and sunflower oil.
How do you know physically if a fatty acid is a polyunsaurated fat?
These fats are liquid both at room temperature and in the refrigerator, and they should never be used for cooking. This might be surprising, given that so many of our standard cooking oils are exactly these unstable vegetable oils.
What is a trans fat?
It’s the trans fat, which is an unsaturated fatty acid that has been either partially or fully hydrogenated
Give examples of trans fats
Baked goods. Most cakes, cookies,
Why are trans fats bad for you?
Although trans fats are edible, consuming trans fats has been shown to increase the risk of coronary artery disease in part by raising levels of low-density lipoprotein (LDL, often termed “bad cholesterol”), lowering levels of high-density lipoprotein (HDL, often termed “good cholesterol”)
What is the metabolic function of lipids? (fatty acids, tryiglycerides)
Break up fatty acids you can release a whole lot of energy, more energy than glucose (burn to form energy)
What are Glycerides?
based on glycerol, 3 carbon chain and fatty acids are esterified into that chain
How do we store fat?
as triglycerides (90% of fat is made from trigiceride : its function is insulation)
Why do aquatic animals have a lot of triglycierdes
For insulation
What is it called when a glycerol has only
a) 2 fatty acids
b) 1 fatty acid
a ) diglyceride
b ) monoglyceride
What are the elements present in lipids?
Carbon, hydrogen and oxygen
What are the smallest lipids made up of?
One molecule of glycerol linked to three fatty acid molecules
What are phospholipids
They are fat-like substances where one of the fatty acids is replaced by a phosphate group
Why are phospholipids so important?
If we have no phospholipids – no life
Why so important? – they form a membrane, no membrane no life. You need membranes for life
Write the sturctural formula for a triglyceride
C - FA
C -FA
C -FA
Draw a structure for a phospholipid and explain how it is used as a membrane?
C - FA
C - FA
C – PHOSPHATE – making the molecule slightly more soluble, attached to phosphate they have a head group
What are the four head groups that are attached to the phopshate on the phospholipid?
Choline (most abundant) base
Ethanolamine
Serine (amino acid)
Inositol (carbohydrate)
Each head group gives rise to four different phospholipids, what are they?
Choline : Phosphatidylcholine
Ethanolamine : Phosphatidylethanolamine
Serine : Phosphatidylserine
Inositol : Phosphatidylinositol
Where can phosphatidylcholine be found?
Phosphatidylcholine is a chemical contained in eggs, soybeans, mustard, sunflower, and other foods
What can Phosphatidylcholine be used for in medical research?
Because the body uses phosphatidylcholine to make a brain chemical called acetylcholine, there is some interest in using it for treating “brain-centered” conditions such as memory loss, Alzheimer’s disease, anxiety, manic-depressive disorders, and a movement disorder called tardive dyskinesia.
What is the most common phospholipid?
Phosphatidylcholine is a strong bilayer-forming lipid and the most common phospholipid in mammalian membranes.
What is the function of Phosphatidylethanolamine?
Phosphatidylethanolamine plays a role in the assembly of lactose permease and other membrane proteins. It acts as a ‘chaperone’ to help the membrane proteins correctly fold their tertiary structures so that they can function properly.
What is the function of Phosphatidylserine?
It covers and protects the cells in your brain and carries messages between them. Phosphatidylserine plays an important role in keeping your mind and memory sharp. Animal studies suggest that the level of this substance in the brain decreases with age
What is the function of Phosphatidylinositol?
play important roles in lipid signaling, cell signaling and membrane trafficking
What are steroids?
Large class of organic compounds with a characteristic molecular structure containing four rings of carbon atoms (three six-membered and one five). They include many hormones, alkaloids, and vitamins.
What is cholesterol?
It is a sterol, a type of lipid molecule, and is biosynthesized by all animal cells, because it is an essential structural component of all animal cell membranes.
Is cholesterol hydrophilic or hydrophobic?
Hydrophobic
What is the importance of cholesterol?
makes membranes a bit more fluid and cholesterol forms basis for a whole range of hormones
List hormones made from cholesterol
Steroid hormones in the body are made from cholesterol: testosterone, progesterone etc
What are eicosanoids?
20 carbon fatty acid-like molecules with very important hormone-like effects
What is the role of Prostaglandins?
cause inflammation in arthritis, pain in headaches
What are the prostaglandins (PG)?
Are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are derived enzymatically from the fatty acid arachidonic acid.
What are Leukotrienes and its function
biologically active compounds, originally isolated from leucocytes. They are metabolites of arachidonic acid
What is the function of Leukotrienes?
Leukotrienes play a key role in asthma in three ways: causing inflammation, bronchoconstriction and mucus production
What are Nucleic acids?
Informational Polymers made of Nucleotides
What are nucleotides made up of?
an organic molecule, called a nitrogenous base; a 5-carbon sugar, called a pentose; and a phosphate group that serves in the phosphodiester covalent bond that forms a bridge between adjacent nucleotides.
What are pyramidines?
6 membered ring
What are purines?
6 membered ring fused to a 5 membered ring
In nucleotides, what is the phosphate attached to?
The sugar
Nucleotides join together to form what?
polynucleotides, each attached via a phosphodiester bond.
How many nucleotides make up genes?
Genes are made up of sets of 3 nucleotides (codons) which encode a sequence of amino acids that form a polypeptide
What is the importance of nucleic acids?
Nucleic acids are vital for cell functioning, and therefore for life. There are two types of nucleic acids, DNA and RNA. Together, they keep track of hereditary information in a cell so that the cell can maintain itself, grow, create offspring and perform any specialized functions it’s meant to do.
What is the process by which monomers are linked together to form polymers?
dehydration reaction protein formation hydrolysis monomerization coiling
Dehydration reaction
In a hydrolysis reaction, __________, and in this process water is __________.
a) monomers are assembled to produce a polymer … produced
b) a polymer is broken up into its constituent monomers … produced
c) monomers are assembled to produce a polymer … consumed
d) a monomer is broken up into its constituent polymers … produced
e) a polymer is broken up into its constituent monomers … consumed
e) a polymer is broken up into its constituent monomers … consumed. The meaning of hydrolysis is “to break with water.”
The type of bond that forms to join monomers (such as sugars and amino acids) into polymers (such as starch and proteins) is a(n) __________ bond.
a) hydrogen
b) Covalent
c) van der Waals
d) ionic
e) peptide
b) Covalent
Monomers are joined together by a dehydration reaction in which two molecules are covalently bonded to each other through the loss of a water molecule.
Generally, animals cannot digest (hydrolyze) the glycosidic linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass?
a) Cows and other herbivores are exceptions and make some cellulose-digesting enzymes.
b) The flat teeth and strong stomach of herbivores break the cellulose fibers so that the cows get enough nutrition from the cell contents.
c) Microorganisms in their digestive tracts hydrolyze the cellulose to individual glucose units.
d) They have to eat a lot of grass.
e) All of the listed responses are correct.
c) Microorganisms in their digestive tracts hydrolyze the cellulose to individual glucose units.
Cows have digestive chambers populated by microorganisms that can produce certain hydrolytic enzymes that cows cannot. The enzymes hydrolyze (digest) the cellulose polymer into glucose monomers.
In what polysaccharide form do plants store glucose to be available later as an energy source?
Starch, glucose storage polymer in plants.
At a conference, the speaker’s grand finale was sautéing mealworms (insect larvae) in butter and serving them to the audience. They were crunchy (like popcorn hulls) because their exoskeletons contain the polysaccharide __________.
a) cellulose
b) chitin
c) palmitic acid
d) collagen
e) glycogen
b) chitin
Chitin is the structural polysaccharide found in arthropod exoskeletons.
Carbohydrates can function in which of the following ways?
a) energy storage
b) information storage
c) structural support
d) enzymatic catalysis
e) structural support and energy storage
e) structural support and energy storage
Carbohydrates function as both storage molecules (starch, glycogen) and structural support molecules (cellulose).
Amylase is an enzyme that breaks down starch. Why cannot the same enzyme break down cellulose?
The glucose monomers in cellulose are bonded in a β glycosidic linkage, whereas those in starch have an α glycosidic linkage. The enzyme amylase is specific for the α glycosidic linkage.
The subunits (monomers) in cellulose are linked together by what?
The glucose monomers of cellulose are linked together by a specific type of covalent bond known as a glycosidic linkage.
How do lipids differ from other large biological molecules?
They are not truly polymers. Their association as a group (fats, phospholipids, and steroids) is related to their solubility behavior.
Nutritionally, saturated triacylglycerols are considered to be less healthful than unsaturated triacylglycerols. What is the difference between them?
For carbon skeletons of equal length, saturated triacylglycerols have more hydrogen atoms than unsaturated triacylglycerols do.
If a small droplet of triacylglyceride molecules is suspended in water, the fat molecules form a “ball of spaghetti” with no particular orientation. But if a droplet of phospholipid molecules is put in water, all the molecules point outward, toward the water. Phospholipids are forced into this orientation, why?
They have a charged or polar end and an uncharged or nonpolar end
Which of the following is a true statement comparing phospholipids and triacylglycerols (fats and oils)?
a) Phospholipids are the primary storage form for fats in our bodies.
b) Phospholipid molecules have a distinctly polar “head” and a distinctly nonpolar “tail,” whereas triacylglycerols are predominantly nonpolar.
c) Both molecules contain a phosphate group.
d) Triacylglycerols may be saturated or unsaturated, but all phospholipids are saturated.
e) In nature, phospholipids occur in fused rings (sterol form), whereas triacylglycerols maintain a straight-chain form.
b) Phospholipid molecules have a distinctly polar “head” and a distinctly nonpolar “tail,” whereas triacylglycerols are predominantly nonpolar
Triacylglycerols consist of three (nonpolar) fatty acid tails attached to a glycerol molecule. Phospholipids have two fatty acid tails and a hydrophilic head containing a negatively charged phosphate group.
The sex hormones estradiol and testosterone belong to which class of molecules?
Lipids
High cholesterol levels are considered a major risk factor for heart disease. If it is so bad for humans, why does the body make cholesterol in the first place?
Cholesterol is the precursor for many important molecules such as sex hormones.
How do manufacturers make vegetable oils solid or semisolid at room temperature?
By adding hydrogen atoms to the fatty acid hydrocarbon chains, thereby converting carbon-carbon double bonds to single bonds
Some lipids are formed when fatty acids are linked to glycerol. These subunits are linked together by __________.
Ester linkages
The fatty acid tails of a phospholipid are __________ because they __________.
hydrophobic … have no charges to which water molecules can adhere
Which of the following lists ranks these molecules in the correct order by size from smallest to largest?
a) glucose, water, sucrose, protein
b) protein, water, glucose, sucrose
c) water, sucrose, glucose, protein
d) water, glucose, sucrose, protein
e) water, protein, sucrose, glucose
d) water, glucose, sucrose, protein
The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the a form. Which of the following could amylase break down?
glycogen, starch, and amylopectin
The structural level of a protein least affected by a disruption in hydrogen bonding is the
a) tertiary level
b) quaternary level.
c) All structural levels are equally affected.
d) primary level.
e) secondary level.
d) primary level
