Biology Part 1 Unit Test PDF

Vocabulary Term Definition Image/Diagram Diffusion Movement of molecules from an area of high concentration to an area of lower concentration (can be through a semipermeable membrane but not...

Vocabulary Term Definition Image/Diagram Diffusion Movement of molecules from an area of high concentration to an area of lower concentration (can be through a semipermeable membrane but not always) Osmosis Movement of WATER molecules from an area of high water concentration to an area of lower water concentration through a SEMIPERMEABLE membrane until equilibrium is reached Apoptosis “Cellular suicide” - when a cell kills itself during the G2 checkpoint of cell division because the damage of the DNA is irreparable G0 - resting If the cell doesn’t pass the G1 checkpoint in cell state division it can enter a resting state until conditions to replicate improve Mutation “Typo” in our genetic code - A permanent change in the cell’s DNA. all cancers start with a mutation which affects a cell’s response to division signals and can be passed to other cells through mitosis (though not all mutations cause cancer) Carcinogen A substance, organism or agent that is capable of causing cancer (e.g. UV light, radiation, chemicals) Benign The safe kind of tumour that is not cancerous. Not invasive and does not spread to other parts of the body because cell division is controlled and at a moderate speed. Relatively harmless unless on the brain Malignant The dangerous kind of tumour that is cancerous. Cell division is unchecked (by the checkpoints) and occurs rapidly. These cells spend little time in interphase and most of the time just dividing. Can spread and damage surrounding cells. Can interfere with the function of other cells. Contact Cancer cells lose their contact inhibition - inhibition normal cells are usually in contact with other cells and stick together, and when cells get too close they stop dividing → this is contact inhibition. When cancer cells lose this they continue to divide even when they are too crowded. Metastasis Cancer cells don’t stick together or to normal cells very well. metastasis → they can spread by moving and dividing in other parts of the body. Because cancer cells can spread so fast it makes it harder to treat. MRS GREND M - movement (ability to bend away, sway or relocate) R - respiration (cellular respiration is performed by the organism) S - sensitivity (ability to detect and respond to changes in the environment) G - growth (ability of an organism to increase in size) R - reproduction (ability to pass on genetic information to offspring) E - excretion (ability of an organism to get rid of cellular waste) N - nutrition (ability of an organism to process nutrients/food for energy, growth + development) D - death (all organisms live only for a limited period of time) The living thing hierarchy Organism - a living individual (e.g. a human) ↓ Organ system - a group of organs that work together to perform a vital body function (e.g. the respiratory system) ↓ Organ - a structure of tissues that performs a specific function (e.g. the heart) ↓ Tissue - a collection of similar cells that perform a common (but limited) function ↓ Cells - an individual unit of life (the basic unit of all living things) ↓ Organelles - tiny “organs” that make up cells Cell Theory 1.​ All organism are composed of one or more cells 2.​ The cell is the basic unit of structure and organization in living things (basic unit of life) 3.​ All cells come from pre-existing cells Overall: the wellbeing of the organism is dependent on the proper function of its cells The organelles Organelle Structure Function Nucleus Round dark circle in the middle Controls cells activities, holds of the cell with a membrane DNA, the nucleolus (inside the surrounding it nucleus) makes ribosomes Centrioles - animal only Groups of 3 hollow rods Active in cell division, spindle (microtubules) fibers pull apart genetic material Cytoplasm Jelly like substance, Maintains the cells internal surrounds/cushions all pressure, chemicals needed by organelles the cell for chemical reactions cell/plasma membrane Thin and flexible, surrounds Controls the flow of materials in the cell, double layer of lipids and out of the cell, semi permeable Mitochondria Oval shaped pod with folds Makes energy for the cell through cellular respiration from breaking down nutrients Golgi apparatus Pancake stack filled with Processes + packages protein to protein be shipped within or out of the cell Endoplasmic reticulum (rough Tubes from the nuclear RER → transports proteins & smooth) membrane to the cell SER → transports fats + steroids membrane Rough → ribosomes attached Ribosomes Small round dots with no Create proteins membrane floating around the cell or on the RER Lysosome - mostly in animal Round dots with a membrane Break down bacteria and waste cells (both have peroxisomes) Vacuole Liquid filled space with a thin Stores mostly water, food and (1 big one in plant cells) membrane waste (many small ones in animal cells) Cell wall - plant only Thick layer of cellulose, Protects + supports plant cell rectangular Chloroplast -plant only Small green discs Contains chlorophyll and is the site of photosynthesis Animal vs. Plant Cells Animal Plant Centriole Chloroplast Round in shape Geometric shape Only cell membrane Cell wall + cell membrane Many small vacuoles 1-2 large vacuoles Prokaryotic cells vs eukaryotic cells Prokaryotes Eukaryotes -​ Always unicellular -​ Unicellular OR multicellular -​ No membrane-bound organelles -​ Many membrane-bound organelles -​ No clearly defined nucleus (only a -​ Clear nucleus nucleoid) -​ Larger + complex functions -​ Small + simple functions E.g. animal, plant, fungus, protist E.g. bacteria, archea Reasons for Cell Division Reproduction: → asexual reproduction (one parent) → genetic information (DNA) is passed from an organism to its offspring Growth: → as an organism grows, the number of cells increases ​ Cells themselves don't usually get bigger because cells have to supply water and chemicals that enter through the cell membrane to the organelles/centre of the cell (through diffusion and osmosis) → if a cell gets too big and reaches a certain size, key chemicals can't reach the organelles fast enough ​ If cells grow to a certain S:V (surface:volume) ratio they have to die or divide S:V ratio explained: if the volume is too big in relation to the surface area and it takes too long to get necessary chemicals to the nucleus the cell must divide Repair: → cells don’t live forever and must eventually be replaced ​ Red blood cells replaced every 120 days ​ Skins cells turn over every 30 days → if you get a cut or break a bone, new cells have to form to repair the damaged tissue Cell cycle: Stage 1: Interphase → has 3 stages → 80-90% of the time the cell is in interphase Gap 1: Cell Growth ​ Rapid cell activity ​ New organelles are made ​ Cell mass & volume increase Synthesis: DNA replication ​ DNA replicates ​ Strands of chromatin duplicate Gap 2: preparation for Mitosis ​ Final growth and preparation period ​ extra proteins, lipids and organelles are made so there is enough for 2 cells Stage 2: Mitosis (PMAT) → prophase → metaphase → anaphase → telophase Prophase: Preparing to split the nucleus ​ Chromatin condenses into chromosomes which are made up of 2 sister chromatids which are attached by a centromere ​ Centrioles move to the opposite poles (ends) of the cell ​ The nuclear membrane and nucleolus begin to break down Metaphase: Middle of the cell ​ Chromosomes line up in the middle of the cell in a single file line  ​ spindle fibers (proteins from centriole) attach to the centromeres Anaphase: away/apart ​ Spindle fibers shorten+pull chromosomes apart from each other ​ Centromeres separate and single strands(chromatids) from each chromosome get pulled to the poles Telophase: two nuclei ​ Single strand chromatids arrive at the poles ​ Chromatids decondense back into chromatin ​ Nucleus and nuclear membranes reform ​ 2 identical daughter cells have formed - but they still share a cytoplasm Stage 3: Cytokinesis (cutting the cytoplasm) ​ Cytoplasm and organelles split in half ○​ Animal cells → “cleavage furrow” ○​ Plant cells → “cell plate” ​ End result is 2 separate and identical daughter cells (each have 23 pairs of chromosomes) Cell division checkpoints The G1 checkpoint:  ​ Occurs at the end of the G1 phase of interphase ​ “Main decision point” - should the cell divide or not? ​ Assess the following things: ○​ Cell size - is it big enough? ○​ Nutrients - enough nutrients and energy? ○​ Molecular signals - is it receiving positive cues from neighboring cells ○​ DNA damage - is the DNA intact and undamaged? ​ If it passes this it becomes committed to Mitosis ​ If it doesn’t pass through this checkpoint it goes into G0 resting state The G2 checkpoint: ​ Occurs at the end of the G2 phase of interphase ​ Looks for evidence of DNA damage and that the DNA replication process was complete during synthesis ○​ If incomplete or damage the cell will try to fix it ​ If irreparable the cell will go through the process of apoptosis ​ This ensures cells with mutations don’t continue to replicate and cause cancer The spindle checkpoint (the M checkpoint): ​ Occurs during mitosis (metaphase) ​ The cell examines if all sister chromatids attach correctly to spindle fibres ​ Because separation of the sister chromatids during anaphase is irreversible ○​ the cell cycle will not proceed until all chromosomes are firmly attached to at least 2 spindle fibres from each side of the cell ​ If not, the cell will pause mitosis and wait for the spindle fibres to capture the chromosome Characteristics of cancer cells: → lose contact inhibition → metastasis → lack of specialization -​ Cancer cells don't specialize as they grow -​ They use the body's energy to grow but do not carry out the work of normal cells -​ If a tumour grows large enough it can interfere with the normal function of other organs, tissues, and cells → abnormal structure -​ Has a small cytoplasm -​ Multiple nuclei (+ large nuclei) because it doesn’t do cytokinesis -​ Coarse chromatin (condensed in chromosomes) -​ Very few cells are ever in interphase Methods for treating cancer 1.​ surgery → removes cancerous tissues → not as effective once cancer has metastasized (spread)  2.​ Chemotherapy → drugs that slow or stop cancer cells from dividing and spreading (but also causes other types of cells to stop dividing) → injected or taken orally → side effects may include, hair loss (hair follicle cells stop dividing), nausea (stops cells in the digestive system from dividing) and fatigue(cancer cells use bodies energy) 3.​ Radiation therapy → cancer cells can be damaged through radiation → the DNA of many of the tumour cells is damaged by radiation so they cannot divide further → involves a highly focused beam of high energy waves directed at the tumour, or a radioactive source into the tumour 4.​ Biophotonics → uses beams of light energy to detect and treat cancer 5.​ Immunotherapies → stimulate and/or boost the immune system to find and attack cancer cells