Lecture 3 - building blocks of cells Flashcards
Building blocks and examples
Building blocks add together to form macromolecules. These include amino acids, nucleobases, simple carbohydrates and glycerol, fatty acids, hydrocarbon rings.
Macromolecules and examples
Macromolecules are made up of building blocks. These include proteins, DNA, RNA, complex carbohydrates and lipids.
Supramolecular assemblies and examples
Supramolecular assemblies form when two or more macromolecules come together. These include membranes, ribosomes and chromatin.
Organelles and examples
Organelles are formed when two or more supramolecular assemblies come together. These include the nucleus, mitochondrial, Golgi apparatus and the endoplasmic reticulum
Amino acids add to form
Proteins
Nucleobases add to form
DNA or RNA
Simple carbohydrates add to form
Complex carbohydrates
Glycerol,fatty acids, hydrocarbons add to form
Lipids
Macromolecules
Organic biological molecules that are necessary for life
Normally composed of thousands of atoms or more, adding up to a large molecular mass
Made up of smaller units known as building blocks (or monomers) that are joined by covalent (chemically strong) bonds
All life is composed of mainly 4 macromolecules - polysaccharides, nucleic acids, proteins and lipids
What are the 4 macromolecules that all life is mainly composed of?
Polysaccharides (complex carbohydrates), nucleic acids (DNA and RNA), proteins and lipids (non-polymeric molecule)
What is a polymeric macromolecule and what ones of the 4 main macromolecules are polymeric?
Polymeric molecules are molecules that are created by polymerisation of building blocks.
Polymeric -Term used to describe examples of or relating to a polymer, or having properties of a polymer.
All polymeric except for lipids
What are the 4 levels of carbohydrates?
monosaccharides (simple carbohydrates a.k.a sugars)
disaccharides (simple carbohydrates a.k.a sugars)
Oligosaccharides (complex carbohydrates)
Polysaccharides (complex carbohydrates)
Monosaccharides
Single unit building block of carbohydrate
There are two groups…
Hexose monosaccharides - there are 6 carbons and they are the building blocks of higher order carbohydrates (longer, more complex carbohydrates)
Pentose monosaccharides - there are 5 carbines and they are usually part of a larger molecule (for example nucleic acids (DNA and RNA))
How to count carbons on monosaccharides
When counting carbons, identify the oxygen atom then count from the one after in a clockwise direction (the one with an oxygen atom does not count)
Also dont forget to look at for side chains
Common hexose monosaccharides
glucose, fructose and galactose
Common pentose monosaccharides
Deoxyribose (part of DNA nucleotide) and ribose (part of RNA nucleotide)
Disaccharides
Two monosaccharides joints together/double unit building block. You get different disaccharides depending on what 2 monosaccharides are joined together.
Common disaccharides
Glucose + fructose = sucrose
Galactose + glucose = Lactose
Glucose + Glucose = Maltose
Oligosaccharides
Several monosaccharides linked together (3-approx 10 linked together)
Polysaccharides
Many monosaccharides linked together, approximately greater than 10 are linked. This is the most common type of carbohydrate we see
Starch
Plant carbohydrate which consists of two components called amylose and amylopectin. Starch is effectively just monosaccharide of glucose linked in a particular way, that way being a branched structure AND linear structure (think about what the surface of a leaf looks like with the lines, some branching but simple pattern effectively)
Glycogen
This is an animal carbohydrate. This carbohydrate consists of glucose molecules linked together in a more highly branched pattern
Cellulose
This is a plant carbohydrate. This carbohydrate is not branched instead glucose monomers are arranged in long chains stack on top of one another and bonded together with hydrogen bones
Carbohydrates are polymers of …
Monosaccharides
What are the 3 functions of carbohydrates?
Recognition
Energy
Structure
Function of carbohydrate - recognition
important for recognition with other cells
Recognise viruses (kick starting the immune system), bacteria (that are not good for the body), recognise antibodies and combine other proteins
Function of carbohydrate - energy
Carbohydrates are in many foods but not all carbohydrates can be used as an energy sources
From plants it is starch and from animals it is glycogen that can be used
Each individual glucose molecule is released and then used by the mitochondria to produce energy for our cells
Function of carbohydrate - structure
Cellulose’s structure means that it can’t be a food source as enzymes are unable to break it up
Therefore cellulose is point in cell walls as it is very important for structure
Nucleic acids
Informational molecules - they tell your cells what to do, when to do it, when to stop/start, how much to do it etc.
Includes deoxyribonucleic acid and ribonucleic acid - both of these are polymers that are made of nucleotides (monomers/individual building blocks)
Nucleic acids are polymers of nucleotides
Nucleotide
Single unit building blocks of nucleic acids
Made up of a negatively charged phosphate group, a base and a ribose sugar
The sugar is slightly different for RNA and DNA in terms of the ribose sugar. On DNA, we have an H atom only on the second carbon and on RNA, we have an OH group instead on the second carbon
Polynucleotides and the common bases
Many nucleotides joined together
Common bases … Thymine Adenine Cytosine Guanine Uracil (U in RNA instead of T)
Complimentary base pairing rule
A binds with T and C binds with G
in RNA all the Ts turn into Us
How are nucleotides connected?
Phosphate group of one nucleotide is connected to the sugar of the next nucleotide etc.
RNA versus DNA structure (basic)
RNA is a single polymer chain
DNA consists of 2 polymeric chains that are twisted into a helix structure (it is a double stranded helix)
For both the bases always point towards the middle
Proteins
They are a macromolecule
Molecule by which cells perform their functions in the whole organism
Proteins are polymers of amino acids i.e. amino acids are the building blocks
Essentially the workers in your cell that make everything happen
There are 20 different amino acids (building blocks) that can make up proteins (general formula H2N-CRH-COOH)
Protein biological functions
Structural - collagen (protein in skin and bones)
Regulatory - insulin (peptide hormone)
Contractile - myosin and actin (muscle proteins)
Transport - Haemoglobin carries oxygen
Storage - Egg white, seed proteins
Protective - antibodies (immune proteins)
Catalytic - hydrolytic in lysosomes
Toxic - Botulinum toxin, diphtheria toxin
Lipids
Not polymers
Hydrophobic (do not like water/ do not want to interact water) (all are hydrophobic)
Heterogeneous (diverse in character/ there are many different types)
Large, chunky and diversely shaped molecular structures
Fat does not mean lipid, fats are a type of lipid
Any of a group of large hydrophobic biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water.
Lipid examples
Triacylglycerols (“fats”) Steroids (sterols) Phospholipids Glycolipids Fat soluble vitamins
Three functions of lipids
structural, regulatory and energy
Lipid function - structural
Structural roles in animal cell membranes - cholesterol (ensures the right consistency) and phospholipids ( important for membrane)
Lipid function - regulatory
Regulatory hormones such as estrogen and testosterone (cholesterol can be used to make estrogen/ these hormones are dervied from cholesterol)
Lipid function - energy
Can provide energy. Lipids are in food, the type of lipid we use for energy is triacylglycerol.
