1041SCG Biological Systems
Study Notes Janis Fernandes
Dear Student, This study sheet was what I used to pass this course and is a comprehensive guide to the subject. I believe that creating notes is a VERY beneficial form of study and I encourage you to add to these notes in a way that works for you. If you need any clarification or help understanding these notes feel free to shoot me an email. If need be we can also arrange an impromptu group/individual tutoring session. Good luck, Janis Fernandes
[email protected] 1041SCG BIOLOGICAL SYSTEMS TOPIC ONE: DOMAINS AND CELLS Introduction to Cells & Domains of Life ● Cells are the smallest living units of life ● They are studied by scientists by use of microscopes ● ALL ORGANISMS ARE COMPOSED OF CELLS Microscopy ● LIGHT MICROSCOPES: Visible light passed through specimen Cell structures magnified with lenses ● ELECTRON MICROSCOPES: Beam of electrons focussed through a specimen (transmission EM) OR on its surface (scanning EM) o SEM: detailed study of a specimen’s surface o TEM: detailed study of a specimen’s internal ultrastructure Eukaryotes & Prokaryotes ● PROKARYOTIC: Bacteria and Archaea o Plasma Membrane o Cytosol o DNA as a single chromosome ▪ Located in the NUCLEOID (no membrane bound nucleus) o Ribosomes o May have a cell wall o SIZE: 0.5-1µm ●
EUKARYOTIC: All other organisms o Plasma membrane o Cytosol o DNA in multiple chromosomes (in a TRUE NUCLEUS; in a membranous nuclear envelope) o Ribosomes o Many extensive and elaborate internal organelles ▪ Lysosomes/peroxisomes ▪ Chloroplasts ▪ Flagella ▪ Vacuoles (only plants) ▪ Plasmodesmata (channels that perforate the cell wall of plant cells and allow cell communication) ● In multicellular organisms, cells come together to form tissues which in turn form organs ● The extracellular components and connections between cells help facilitate their cellular activities. Cell Structure o CELL WALL Extracellular structure of plant cells that distinguishes then from animal cells Made of cellulose fibre embedded in polysaccharides and protein May be multi-layered Nervous Tissue
2 types of cells o Neurons: Transmit matter through the nervous system through signals in the form of electrical currents which pass from one endo of the nerve to the other. Transmission of information across a synapse; mediated by specialised molecules, neurotransmitters Neurotransmitters include: o Acetylcholine o Biogenic Amines (eg dopamine, serotonin, norepinephrine) o Amino acids o ATP o Peptides o Dissolved gases
Typical neuronal cell structure
Soma: the cell body o Contains: Nucleus, ER, Mitochondria, extensive cytosol, ribosomes
Dendrites (extensions of the cell cytoplasm) o Receives information from other cells Axon: Nerve fibre o Transmits information away from the cell body and through the terminal boutons which meet junctions of other cells (dendrites) at a synapse
REVISION QUESTIONS: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
What is the Great Chain of Being? What are Darwin’s five key features of evolution? Why is the left ventricle so thick? What are the four stages of food handling? What are the differences between the CNS and PNS? Which is the largest section of the mammal brain? What are hormones? What does testosterone do? Name the four major lineages of plants List three derived features of land plants Explain alteration of generations What is the advantage of “walled spores”?