Biology Basics Quiz

Course Information

• Course Title: BIO101 – General Biology/FSC111 - Introductory Biology
• Lecturer: S. Taiwo Fakorede, Ph.D.
• Department: Department of Cell Biology and Genetics
• University: University of Lagos, Nigeria

Learning Objectives

• Define biology in a scientific sense
• Describe the characteristics of life
• Understand the relationship between structure and function
• Formulate hypotheses, design experiments, analyze data, and draw valid conclusions based on evidence

What is Biology?

• The study of life
• The science of life
• Biologists study life in all its forms, from single cells to the interactions of millions of organisms

What is Life?

• Living things have specific characteristics
• An object is considered alive if it displays all of these properties

Characteristics of Life

• Cells: All living things are made of cells.
• Order: Living things are complex and ordered.
• Sensitivity or Response to Stimuli: Living things respond to their environment.
• Reproduction: Living things reproduce their own kind to keep the species alive.
• Adaptation: Environment influences survival.
• Growth & Development: Growth and development throughout life.
• Regulation: Coordination of internal functions.
• Homeostasis: Maintaining internal balance.
• Energy Processing: Performing metabolism.

Levels of Organization of Living Things

• Atom: Smallest and fundamental unit of matter, has a nucleus surrounded by electrons.
• Molecule: Two or more atoms held together by a chemical bond.
• Macromolecules: Large molecules formed by combining smaller units called monomers.
• Organelles: Molecules form small structures within cells performing specialized functions.
• Cell: Fundamental unit of structure and function, all living things are made up of cells.
• Tissues: Groups of similar cells carrying out the same function.
• Organs: Collections of tissues grouped together based on a common function.
• Organ System: Functionally related organs.
• Organisms: Individual living entities.
• Population: All individuals of a species within a specific area.
• Community: Set of populations inhabiting a particular area.
• Ecosystem: All living and abiotic (non-living) things in a particular area.
• Biosphere: Collection of all ecosystems, represents the zones of life on Earth.

Classification of Organisms

• Prokaryotes: Single-celled organisms without a membrane-bound nucleus or organelles; e.g., Bacteria.
• Eukaryotes: Organisms with cells that have a membrane-bound nucleus and other membrane-bound organelles; e.g., Plants, Animals, and Fungi.

Unifying Themes of Biology

• Cells: Basic structural and functional units of life. Two main groups: prokaryotic (simple, small cells) and eukaryotic (more complex with organelles). Bacteria are prokaryotic, Plants, Animals and Fungi are eukaryotic.
• Systems: Interacting parts working together to form a whole. Systems exist at all levels of biological organization. Examples: single heart cell, nervous system, digestive system, ecosystem (forest or desert).
• Structure and Function: Structure determines function. Different structures and shapes associated with different functions within an organism.
• Emergent Properties: New properties emerge at each level of organization, resulting from interactions among components at lower levels. An organism achieves more than what individual cells could achieve.
• Reproduction and Inheritance: Organisms produce new organisms like themselves; hereditary information is encoded in DNA (DNA → RNA → Protein).
• Homeostasis: Maintenance of constant internal conditions to survive in variable environments. E.g., sweating, blood flow to cool the body.
• Interactions: Relationships between organisms and their environments at all levels. Ecology is the study of such interactions.
• Evolution: Change in living things over time, through natural selection of adaptations. Adaptations are beneficial inherited traits.
• Scientific Inquiry: Discovery science uses observation and measurement to describe phenomena; Hypothesis-based/Experimental science explains phenomena based on data. Both depend on logical reasoning: induction (specific→general) and deduction (general→specific)

The Scientific Method

• Observation: "Seeing" something or a new idea by reasoning; an unexplained situation.
• Question: A question about the observation.
• Hypothesis: A testable explanation for the observation. Must be testable and falsifiable.
• Prediction: A statement about the expected outcome of the test of the hypothesis.
• Experiment: Test of the hypothesis using a controlled experiment; data collection.
• Data Collection & Analysis: Gather data to analyze, and determine results.
• Results: Data collected from the experiment.
• Deductive Reasoning: Using a general principle to forecast specific results.
• Conclusion: Summary of results, determining if the hypothesis is rejected or accepted/supported. May lead to a scientific theory.
• Variables: Independent Variable (IV): factor manipulated by the researchers. Dependent Variable (DV): outcome measured or recorded. Standardized Variables (SV): factors kept constant. This includes control experiments, positive controls and negative controls.
• Scientific Theory: A hypothesis that has had many successful experimental tests over time. Theories explain data in a simple set of concepts, raise new questions, and may change over time.

Biomolecules and the Central Dogma of Life

• What are Biomolecules? Molecules occurring naturally in living organisms including small ones like primary and secondary metabolites and natural products; usually obtained from food.
• The four major classes: Carbohydrates, Lipids, Proteins, and Nucleic acids
• Monomers and Polymers: Large biomolecules (polymers) are built from smaller units called monomers (e.g., monosaccharides are monomers for carbohydrates). Dehydration and Hydrolysis reactions are involved in building and breaking down polymers.
• Chemical Elements: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), and sometimes sulfur.
• Structure of DNA and RNA: DNA is a double helix, consisting of nucleotides (nitrogen base, sugar, and phosphate); RNA is single-stranded. Key nitrogenous bases include Adenine, Guanine, Cytosine, Thymine, and Uracil (RNA).

Biological Organisation and Levels of Organisation of Living Things.

• A hierarchy of organisation at different levels of organisation. Starting from the simplest unit, which is atom, molecule (consisting of 2 or more atoms), large molecules, cells, tissues, organs, system (organ), organism, population, community, ecosystem to finally the entire biosphere.

DNA Replication

• Process of making copies of DNA; a single strand of DNA serves as a template for the new strand. Base pairing rules are crucial.
• The process occurs in the S-phase of the cell cycle. There are three (3) models of replication - Semi-conservative, Conservative and Dispersive. Meselson and Stahl experiment supported the semiconservative theory. Replication Enzymes and their functions. (helicase, topoisomerase, primase, DNA Pol III and I, and Ligase). Replication fork and its components.

DNA, mRNA, and tRNA

• Transcription: Process making RNA (mRNA) from the DNA template.
• mRNA: messenger RNA, carries message from the DNA to the ribosome to synthesize protein.
• tRNA: transfer RNA, carries amino acids to mRNA at the ribosome site to build protein polypeptide chains.
• Processing RNA: (A separate discussion on processing pre-mRNA to mRNA would be crucial here, as the process is important to protein synthesis).
• Translation: Process of synthesizing protein (polypeptides) from mRNA by Ribosomes and tRNAs.

Genetic Code

• Set of rules where mRNA codons specify the amino acids in protein. The codon consists of three bases. There are 64 codons, where 61 code for amino acids, and three code for STOP codons. The code is degenerate and nonoverlapping.

Protein Synthesis

• Steps of protein synthesis, including transcription and translation, starting from DNA to mRNA to amino acid sequence, the process of protein folding and its structure, and the genetic code of DNA as applied to protein synthesis. Mutations and diseases (e.g., sickle cell anemia) resulting from changes in DNA sequences.

Assignments

• Assignment I: contributions of scientists to understanding DNA structure and function.
• Assignment II: describe Meselson and Stahl experiments in detail. Describe the results if the experiment continues for three, four, and five generations.
• Assignment III: compare and contrast DNA replication on the leading and lagging strands.
• Assignment IV: detailed analysis of a DNA template to illustrate complimentary base pairing, mRNA transcription, tRNA anticodons, number of amino acids, and resulting protein sequence.

Test your knowledge on the fundamental characteristics of life and the principles of biology. This quiz covers topics such as adaptation, homeostasis, and cellular structures. Perfect for students studying introductory biology or anyone interested in the science of life.