Biological Molecules Flashcards
(19 cards)
Which elements do each of the types of biological molecules consist of?
- carbohydrates
- carbon
- hydrogen
- oxygen
- ratio of 1 carbon : 2 hydrogen : 1 oxygen
- lipids
- carbon
- hydrogen
- oxygen
- proportion of oxygen much lower than in carbohydrates
- nucleic acids
- carbon
- hydrogen
- oxygen
- nitrogen
- phosphorus
- proteins
- carbon
- hydrogen
- oxygen
- nitrogen
- sulfur
Which different kinds of carbohydrates are there?
Carbohydrates include:
- Monosaccharides (“simple sugars”)
- glucose
- fructose
- galactose
- Disaccharides, two monosaccharides linked together
- sucrose (glucose and fructose)
- lactose (glucose and galactose)
- Polysaccharides, large, complex carbohydrates with many monosaccharides linked together
- starch
- glycogen
- cellulose
Where are some different exmaples of sugars found, and what are their functions?
- glucose
- found naturally in many sweet-tasting foods, such as fruits and vegetables
- during cellular respiration, cells release energy by oxidising glucose
- fructose
- fruit sugar
- lactose
- milk sugar
- sucrose
- ordinary table sugar
- main sugar transported through plant stems
- starch
- large, insoluble molecule
- storage carbohydrate in many plants
- glycogen
- found in animal tissues such as the liver and muscles
- storage of energy as glucose for later release
- cellulose
- makes up plant cell walls
- humans cannot digest cellulose
- cleans out our intestines
What is the difference between animal and plant lipids?
- most animals have lipids that are solid at room temperature but melt if you warm them up and are called fats
- most plant lipids are usually liquid at room temperature and are called oils
Are lipids good for us?
Although they are an essential part of our diet, too much lipid is unhealthy, especially:
1. saturated fats
- Saturated lipids are more common in food from animal sources, such as meat and dairy products.
- There is evidence that unsaturated lipids are healthier for us than saturated ones.
2. cholesterol
- Substance that the body gets from food such as eggs and meat, but we also make cholesterol in our liver.
- It is an essential part of all cells.
- But too much cholesterol causes heart disease.
What is the structure of nucleic acids?
Nucleic acids are polymers of nucleotides that have a general structure containing a phosphate group, a sugar molecule and a nitrogenous base.
What is DNA?
DNA (deoxyribonucleic acid) is a very large and complex molecule. It is found in the nucleus of cells and carries the genetic code of an organism, which is structured in the form of a double helical structure with the two strands being held together by a series of base pairs.
What does the DNA consist of?
A molecule of DNA is made from two strands of molecules called nucleotides. Each nucleotide contains a sugar molecule (deoxyribose), a phosphate group and a nitrogen-containing group called a nitrogenous base. There are four bases in DNA namely adenine (A), thymine (T), cytosine (C) and guanine (G). Please note that in DNA adenine always bind to thymine while cytosine always binds to guanine (A and T are complementary bases while C and G are complementary bases). This is known as the base-pairing rule.
What does the RNA consist of?
Unlike DNA, a molecule of RNA consists of a single strand of nucleotides. In RNA, each nucleotide also contains a sugar molecule (in this case ribose), a phosphate group and a nitrogen-containing group called a nitrogenous base. There are also four bases in RNA namely adenine (A), uracil (U), cytosine (C) and guanine (G). In RNA, adenine always bind to uracil while cytosine always binds to guanine (A and U are complementary bases while C and G are complementary bases).
What are some examples of foods rich in animal fats?
- meat
- butter
- cheese
- milk
- eggs
- oily fish
What are some examples of foods rich in plant oils?
- many types of oils used for cooking:
- olive oil
- corn oil
- grapeseed oil
- products made from oils:
- margarine
What do the parts of the name “carbohydrate” refer to?
- “carbo” refers to the carbon atoms
- “hydrate” refers to the hydrogen and oxygen atoms
How much of the mass of the human body does each element make up?
- carbohydrates: 1%
- lipids: 10%
- proteins: 18%
- nucleic acids: ?
What are the roles of each of the types of biomolecules?
- carbohydrates
- body’s main ‘fuel’ for supplying cells with energy
- lipids
- form cell membranes of all cells
- fat is deposited in certain parts of the body as a long-term store of energy
- proteins
- enzymes (speed up reactions)
- antibodies (defend the body)
- some hormones (signals)
- nucleic acids
- ?
What are the building blocks of complex sugars?
The building blocks of larger carbohydrates are simple sugars.
What is the chemical formula of glucose?
C₆H₁₂O₆
What is the difference between saturated and unsaturated fatty acids?
- ‘Saturated’ is a word used in chemistry, which means that the fatty acids of the lipids contain no double bonds.
- Other lipids, which are more common in plant oils, are unsaturated, which means that their fatty acids contain double bonds
- Unsaturated fatty acids include monounsaturated (one double bond) and polyunsaturated (more than one double bond) fatty acids.
Which are some different examples of lipids?
The diverse lipid family includes triglycerides (fats and oils), phospholipids (lipids that contain phosphorus), steroids and fat-soluble vitamins (vitamins A, D, E, and K).
Which are the building blocks of lipids?
The chemical building blocks of lipids are two types of molecules called glycerol and fatty acids. Glycerol is an oily liquid. It is also known as glycerine, and is used in many types of cosmetics. In lipids, a molecule of glycerol is joined to three fatty acid molecules. There are many different fatty acid molecules, which give us the many different kinds of lipid found in food.
