luke o neill
Life - complex chemicals interacting
What is the basis for nutrition
Molecular level - dna
Atomic level - oxygen tnf
Organelle level -nucleus
Cellular level
Tissue level
Organ level
Organ system level
Organsim level
Higher levels - population
Cell - fibrolasts - cells that make your joint tissue - macrophage cell in particular gene in macrophage makes the protein tnf
Drug used to stop the tnf is called humra - slows the disease by about 70-80%
No idea the trigger for this disease
Features of life
Energy utilisation
Movement
Growth
Reproduction
Homeostasis
Response
Order and complexity
Evolution
Van leuwick first to see the microscope world
Robert hooke coined the term cell
SCHEIDEN AND SCHWANN- the cell theory
All living thing are made from cells
All cells arise from pre existing cells
Cells can live alone - unicellular or together multicellular
Subcelluar structures
Nucleus - dna
Gogli - a cell organelle that helps to process and package proteins and lipids molecules especially those destined to be exported -protein factory -a factory in which proteins received from the ER are further processed and sorted for transport to their eventual destinations: lysosomes, the plasma membrane, or secretion
Lysosomes- an organelle capable of breaking down various biological polymers
Endoplasmic reticulum- a large structure with many role including calcium storage and lipid metabolism - surroundsw the nucleus of a cell
The central dogma theory - a theory stating that dna flows only in one direction from DNA to RNA to protein and does not reverse - this applies to all living things
Chemistry of life
The elements are arranged into complex chemicals:
Purines - Nucleotides: ATP (energy), GTP (communication)
Pyrimidines- Nucleic acids: DNA and RNA (information)
Amino acids- make Proteins (structures, enzymes, carriers, receptors, messengers)
Lipids func.(structure, energy, messengers)
-Fatty acids
-Glycerides
-Phospholipids
-Steroids
-Cholesterol
Sugars -Carbohydrates func. (structure, energy)
Combinations: Glycolipids, Glycoproteins, Lipoproteins
CARBON FORMS THE BACKBONE OF ALL OF THESE WE ARE A CARBON-BASED LIFE-FORM- carbon forms four bonds which makes it unique ( silicone also does this )
Evolution of this -
Earth forms 4.5 billion years ago (abiotic)
-First sign of life: 4.2 billion years ago: chemical signature for life -biochemicals start to appear
-Oldest prokaryote: 3.5 billion years ago: took a billion years for life to evolve
Evidence is based on chemistry and fossils
How did we get to the first cell
Abiotic - no life evidence of life at all
Prebiotic world(before life begins) - rich in organic building blocks
Early conditions needed to be correct in order to allow the synthesis of complex biochemicals
There was NO oxygen
There had to have been an energy source - uv light - to allow for catalysis of electrochemical energy
The atmosphere must have been reducing- oxidizing would have destroyed stuff
There also had to be water
Millers and vrey experiment
Test tube - h20 h2 ammonia and methane
system of heat
Uv light shown to the other tube
Condenser
Samples taken at regular intervals
They found amino acids - the building blocks of proteins
Know that diagram and draw it
1953 - also the year double helix was formed - annus mirabilis - remarkable year
Latest - hydrogen cyanide hydrogen sulphide uv light = nucleotides amino acids lipids
Suspect rna came first before dna as rna can act as information and a catalyst or enzyme
Abiotic - prebiotic - RNA world - now
Latest - hydrogen cyanide hydrogen sulphide uv light = nucleotides amino acids lipids
Suspect rna came first before dna as rna can act as information and a catalyst or enzyme
Microscopic organisms evolved through random evolution and allow them to combine the dna to energy
Before this energy came from the volcanos or earth
This energy is then used to make carbohydrates - the pigment is now green chlorophyll but before suspected to be purple
Toxic chemical starts to build up o2 - oxygen is very oxidizing
A mass extinction happens
All the creatures cant survive the oxygen
Some bacteria hide in o2 poor environments- these r still around as anaerobic bacteria
Plant cell goes inside a bacteria - this forms a cell that can make carbs burn them to make oxygen it can also use the energy made
Endosymbiosis - when one organism is living inside another organism
Evidence for endosymbiosis
Mitochondria and chloroplasts have dna
Mitochondria membrane looks like the bacteria membrane
Nuclei begin to appear
First multicell life begins to appear
Slime mould a type of amoeba that can live and single r multicell in cases of hunger
Hydra - a multi cell cell specialisation begins to happen
Multicellular life evolves - CElL SPECIALIZATION
Single cell can become a spore
Once multicellular organisms start evolving, the possibilities become almost limitless – we finally reach us
Humans are made of approx300 different cell types
Each cell type is defined by specific gene expression – all cells have All genes, but not all genes are expressed in all cells Eg: B lymphocytes make antibodies, gut epithelial cells make digestive enzymes
Cells are organised into tissues:
Skin: fibroblasts, keratinocytes
Muscle: smooth, skeletal and cardiac muscle cells
Joints: fibroblasts, chondrocytes
Bone: osteoclasts, osteoblasts
Brain: neurones, glial cells
Blood vessels: endothelial cells
Inner surfaces (linings): epithelial cells
Blood: Lymphocytes, macrophages, neutrophils, erythrocytes
Sections 2 - cellular basis of life - lecture one
Cells are made of biomolecules
Dna - contains code for protein
Proteins - products of genes
Lipids - give structure
Carbohydrates- provide energy for growth and replication
Carbon -based lifeforms
Hydrogen -bonding
Oxygen
Nitrogen nitrogenous babes
Phosphorus - backbone of dna
Sulfur -disulphde bonds
H20 - solvent (exam q)
Examq how these react as and in water
What is life
Capacity for growth and self replication
Processes - metabolism homeostasis response to stimuli
Inheritance of genetic material
Biomolecules - proteins carbohydrates lipids nucleic acids dna and rna
Features of cells
Nuclear region - genetic material but proteins protect
Plasma membrane - separates cell from outside and maintains order allows transport is made from phsoslipids and proteins
Cytoplasm - organelles
The transmission of genetic material and the processes to support this are facilitated by cell structure
There are three domains to life:
Bacteria
Archea
Eukaryotes
The domains are split into prokaryotic and eukaryotic
Prokaryotic - no true nucleus
Nuclear region called nucleoid
No membrane bound organelle - metabolism takes place in cytoplasm
Cell wall provides structure and rigidity
1-5 micrometrers
Eukaryotic
True nucleus
DNA Within nucleus, nucleolus region
Membrane-enclosed
Contain organelles (eg-Mitochondria)
“Division of labor”
No Cell Wall – more fluidic shape
Larger cells 10-50 μM
Smaller cells have higher surface to volume ratios allowing them take in more nutrients etc
The nucleus of the cells
Chromosomes -contain dna packaged in proteins called chromatin
nucleolus - area rich inn ribesomal dna
Nuclear envelope - Two phospholipid bi-layer’s form the Nuclear Membrane Studded with Nuclear Pores Allows transport of RNA out & signals inward…
There are seven kingdoms of life
Eukayotic
Fungi
Animalia
Plantae
Protista
Chrmista
Prokaryotes
Bacteria
Archaea
The nuclear side of the envelope is
lined by the nuclear lamina, which is
composed of proteins and maintains
the shape of the nucleus
A double helix structure provides - structure
Allows replication to occur
Allows transcription to occur so only certain sequences can be copied to rna
Dna + histone proteins =nucleosomes to chromatic to chromosomes
Transcription
Dna to mrna ( rna polymerase and rna nucleotides )
DOUBLE HELIX STRUCTURE ALLOWS:
- DNA REPLICATION – whole genome unwinding & copying chromosomes
- DNA TRANSCRIPTION – regulated unwinding of specific genetic
sequences/genes, creation of “RNA” copy
Dna
Sugar component - deoxyribose
Thymine as base
Stable structure
Double strand
Rna
Ribose
Uracil
Unstable and temporary
Single stranded
mRNA
Translated to proteins exported from nucleus to site of protein synthesis- the ribesomes
rRNA
Forms a complex with proteins in the ribesome
Site of protein synthesis
tRNA transfer rna
Links amino acids up to proteins
Ribesome (protein and RNA complex) acts as a catalyst for mRNA to Protein
Ribesomes are not actually organelle because they arent membrane enclosed and can be found in prokarytic cells aswell as eukayotic
One m rna can make multiple copies of a protein
Ribesomes r found in both pro and eukaryotic cells
They are the central flow of all genetic information
Translate mRNA into PROTEINS
Complex of rRNA, proteins,
tRNA & mRNA
Found free in cytoplasm
Or
associated with Endoplasmic
Reticulum (ER)
– membrane network from
nucleus into cell
The fate of proteins
Structural metabolic
Transport
Enzymes
Acid base balance
Hormones
Antibodies