Biology Notes PDF

Biology Notes 🦠 Parts of a cell: - Mitochondria Converts stored energy into a usable form - Vacuole Fluid in a sac, removing unwanted material, and maintaining internal fluid pressure - Chloroplast (P) Absorbs light and energy and generates nutr...

Biology Notes 🦠 Parts of a cell: - Mitochondria Converts stored energy into a usable form - Vacuole Fluid in a sac, removing unwanted material, and maintaining internal fluid pressure - Chloroplast (P) Absorbs light and energy and generates nutrition, also giving it the green color (photosynthesis) - Cytoplasm All organelle inside the cell is suspended in the cytoplasm - Lysosomes Breaks down food using chemicals - Cytoskeleton Holds the cell structure - Nucleolus Produces ribosomes - Cellular Membrane Supports the cell, and allows some substances to enter and keep others out. - Ribosomes This reads genetic information and uses it to generate proteins - Golgi Collects materials to be removed from the cell - Endoplasmic Reticulum This transports materials throughout the cell - Nucleus Controls all the genetic information, and cell activity, including Chromosomes, and DNA - Cell wall (P) Provides support for the cell, and protects it from physical injury  Prokaryotes Similarities Eukaryotes - No Nucleus - Living organism - Has a Nucleus - Does not have an - Has DNA - Has organelle organelle - Unicellular organisms - Complex - Simple - Multiple strands of - Singular strand of DNA DNA Osmosis: This is the movement of water from a high concentration to a less concentrated amount of water Diffusion: This is the movement of anything except water from a high concentration to a less concentrated amount. DNA: (Deoxyribonucleic acid) DNA is made up of 23 pairs of chromosomes Each pair is different and they are called Karyotypes The Chromatid, is a single strand of chromosomes The Centromere, is where the two chromatids meet it holds them together It is made up of: Pentose sugar (deoxyribose) Phosphate group Nitrogenous bases (Adenine, Guanine, Thymine, Cytosine) C always binds with G A always binds with T The base pairings are always read in a sequence of three codons If for instance, something gets paired incorrectly it can create mutations and cancers. Example: Stand 1: AAT - GCA - TGA - TCA Strand 2: TTA - GCT - ACT - AGT Types of mutations: Base substitutions: An alteration of bases AAG-CTG-CAG AAG-CTT-CAG Base insertion: Adding a base AAG-CTG-CAG AAG-CTG-CAG C Base deletion: Subtracting a base AAG-CTG-CAG AAG-CTG-CA. Effects of Mutation: Neutral: Eye Colour (No effect) Deleterious: Function is deleted Lethal: Kills organism (Miscarriage) Beneficial: Benefits Organism (Sickle cell) What if someone who has a mutation tries to reproduce? Binary Fission: Binary fission is how prokaryotes or single-celled organisms reproduce, there are three steps involved, The DNA duplicates, it splits and then it divides (Asexual Reproduction) Mitosis: Mitosis is the way that most Eukaryotic cells reproduce including humans, Here there are six phases: Interphase: - The nuclear envelope disintegrates - DNA duplicates - Centromeres get created - Chromatin is thread-like Prophase: - Chromatin looks much thinner - The centromeres attach to the kinetochores of the chromosomes Metaphase: - A line of chromosomes is created Anaphase: - The chromosomes divide - The centromeres pull them to opposite poles with the spindle fibres Telophase: - The DNA reaches the poles - The spindle fibers are removed Cytokinesis: - The cytoplasm divides to create two daughter cells - The nuclear envelope reappears Apoptosis Programmed cell death (cell suicide) is when cells are no longer needed or if the cell is copied incorrectly Necrosis Death of a cell due to external factors, caused by toxins, radiation, infections, and trauma