Biology - Lecture Notes

Biology Compare the structures and functions of the major biological molecules (carbohydrates, proteins, lipids, and nucleic acids) as related to the survival of living organisms. Chemistry • A Macromolecule is a large molecule. If a molecule had carbon than it is considered an Organic molecule. • There are four main macromolecules that are important to biology: carbohydrates, lipids, proteins, and nucleic acids Carbohydrates- these are sugars used for quick energy. Their building blocks are monosaccharides. Remember many sugars end in -ose Elements made of Carbon, Hydrogen and Oxygen in a 1:2:1 ratio. Types: Monosaccharides---- one sugar----examples Glucose which is made in photosynthesis Fructose which is in honey and fruit Glucose Disaccharides--2 sugars or 2 monosaccharides connected--Example sucrose is table sugar Polysaccharides---many sugars- examples Cellulose is in cell walls Starch is used for plant energy storage Glycogen used for animal energy storage in the liver Lipids- these are fats, waxes and oils. They are used for long term energy storage and for the cell membrane. Also used for insulation to protect animals from the cold. These are made of long chains of carbon and hydrogen and a little bit of oxygen. Triglyceride- is a fat made of a glycerol backbone and three fatty acid chains. Phospholipids: fats that make up the cell membrane Steroids: fats which are in rings instead of chains like cholesterol Examples of lipids: 1 Proteins- Made from amino acids which are held together by peptide bonds. There are 20 amino acids. They are made in the ribosome. Proteins fold in a 3D shape and this shape determines their function. Important Proteins: • Enzymes (see enzymes in this packet) • Hemoglobin- a protein in a blood cell that helps carry oxygen in the blood. • Insulin- a protein in the body which helps maintain proper blood sugar levels (homeostasis). If there are problems making insulin than a person could have diabetes. Nucleic Acids: These molecules are our inherited genetic information. The two main examples are RNA and DNA They are made of Nucleotides. Nucleotides are made of a phosphate, sugar, and base. base Bio.4.1.3 Explain how enzymes act as catalysts for biological reactions. Enzymes • Enzymes can also be called Catalysts. Several enzymes end with –ase. Ex. Lactase, Maltase. They can be used over and over again. • These are proteins that help speed up reactions. Without them most of the reactions that happen in our body would happen so slowly that we would die. They are reusable. • People who lack the enzyme Lactase are Lactose intolerant. Meaning they cannot break down the sugar, lactose, in dairy products. So if they were to drink milk they would have an upset stomach. • Every reaction needs a certain amount of energy to start (activation energy). Enzymes lower the amount of activation energy needed. Since the reaction doesn’t need as much energy it can go faster. 2 • Enzymes fit together with substrates. Substrates are whatever chemical the enzyme is working on. They fit like a lock and key. Enzymes only fit their specific substrate. • The place where the substrate fits into the enzyme is called the active site. The enzyme’s 3D shape is linked to its function. • If you change the shape of the enzyme it won’t work anymore. You can do this by changes in temperature or pH level. It’s called denaturation. *Remember the words optimum and optimal mean best or highest! 3 Understand the relationship between the structures and functions of cells and their organelles. Summarize the structure and function of organelles in eukaryotic cells: Compare prokaryotic and eukaryotic cells in terms of their general structures (plasma membrane and genetic material) and degree of complexity. • Cells To see a cell you must use a microscope. To determine the magnification you are using multiply the lens by the objective. Example: If the lens has a 10x magnification and the objective has a 40x magnification then you are seeing the cell at a 400x magnification. There are two main types of cells Prokaryotes and Eukaryotes • Prokaryotes do NOT have a nucleus or any other organelles. They do have ribosomes, DNA, and plasma membrane. They are small, microscopic, unicellular,and less complex. Take the “P” and turn it upside down for a “B”= Bacteria! Ribosomes (the dots) DNA or Plasmid Flagella A plasmid is circular DNA. Cilia Cell Membrane Cell wall • Eukaryotes DO have a nucleus and all organelles. Animals, plants, protists and fungi are all eukaryotes. Can be multi or unicellular, are larger, and more complex. Important Organelles: A. Nucleus- “the brain of the cell” Controls all cell functions. DNA is inside. B. Cell/plasma membrane- controls what enters and leaves the cell. Homeostasis C. Ribosomes- these make the proteins in the cell D. Mitochondria- “powerhouse” of the cell. Provides energy by Cellular respiration. E. Cell wall- this is not in animals. Provides protection and support for the cell F. Chloroplast- this is only in plants and protists. This is where photosynthesis happens. It contains a pigment called chlorophyll which keeps the plant green and captures light energy. G. Vacuole- Large vacuole only in plants. It stores food, water, enzyme, and waste. 4 Plant Cell Animal Cell C. Ribosomes are dots E B B A D G C. Ribosomes are dots A F D Cell Differentiation Explain how instructions in DNA lead to cell differentiation and result in cells specialized to perform specific functions in multicellular organisms. • Organisms begin as undifferentiated masses of cells. Variation in DNA expression and gene activity determines the differentiation and specialization (job) of these cells. • All cells have the same DNA and genes. However, genes are activated or turned on and off in cells to specialize them or determine their job. This is called differentiation. For instance a muscle cell will have different genes activated than a blood cell. Chemical signals are released to control gene activation. Once a cell is differentiated it cannot be changed. Cells are specialized to perform particular functions. For instance: A blood cell is flat and small so it can move easily through the vessels. A nerve cell or neuron is long and thin to pass information signals to the next cell. The sperm’s tail allows it to travel to the egg and enzymes in the head allow it to enter the egg. Muscle cells contain fibers which allow the cells to move by shortening or contracting. Stem cells are cells that are not specialized or do not have a job yet. They are undifferentiated. They can become any cell in the body. Where can you find stem cells? • Embryonic stem cells are in embryos (baby). • Adult stem cells can also be found in adult organs like in the bone marrow. • They can be made in the lab from Induced Pluripotent cells (IPS) or cloning. Because stem cells have the potential to replace many cells in the body they could potentially cure many diseases. However, the use of embryonic stem cells is controversial since they result in a destroyed embryo. 5 Explain how homeostasis is maintained in a cell and within an organism in various environments (including temperature and pH). Explain ways that organisms use released energy for maintaining homeostasis (active transport). Transport in the Cell • The plasma membrane controls what enters and leaves the cell. It maintains a balance on the outside of the cell and on the inside = homeostasis or equilibrium. • Another name for the plasma membrane is the Phospholipid bilayer= 2 layers of fat. • The plasma membrane is semi or selectively permeable.This means it only lets some things through. • Solutes- anything dissolved in water like salt or sugar. It cannot move through the membrane without energy. • There are two types of transport= Passive and Active • Active transport requires energy (ATP). It moves materials from low to high concentration and requires the help of carrier proteins. It goes against the concentration gradient. It usually moves big molecules like carbohydrates. Low • High Passive transport does not require any energy. Moves small molecules. It moves with the concentration gradient. 3 Types of passive transport: Diffusion moves materials from a high to low concentration. Facilitated Diffusion uses carrier proteins. Osmosis- the movement of water from an area of high to low concentration across a membrane. It’s the diffusion of water. 6 Osmosis = Solute 70% water 45% water Water would move from high to low and leave the cell = solute 10% solutes 60% solutes This means there is 40% water inside and 90% water outside. So water will move in. There is high water on left and low on right. So water will move towards the right. Making the right side higher. Homeostasis is maintained in other ways in the body. • Temperature: when you are too hot you sweat to reduce your body temperature and when you are too cold you shiver to raise your body temperature. • Your cells need to maintain a neutral pH (7) so there are buffers in the blood that helps to keep your blood from getting to acidic or too basic. • Your body works to keep your blood glucose (sugar) levels balanced. Insulin helps keep this balance and an imbalance can cause Diabetes. 7 Energy Analyze photosynthesis and cellular respiration in terms of how energy is stored, released, and transferred within and between these systems. Photosynthesis= putting together with light. Converting radiant (sun) energy to chemical energy (food). • This is the process where producers/autotrophs make their own food (glucose). The energy for this reaction is from the sun. • Reactants (ingredients) = water, carbon dioxide, and light (remember plants are opposite of us...we breathe in oxygen they breath in CO2) Products (what you get) = glucose and oxygen The stoma or stomata Guard cells • You must know the formula: • Photosynthesis happens in the chloroplast of the cell. Since animals do not have chloroplasts they cannot perform photosynthesis. The chlorophyll is pigment in the chloroplast that absorbs the sunlight and makes the plant green. Chloroplasts are often located at the top of the leaf since that is the area exposed to the most sunlight. • The Carbon dioxide enters the leaf and the oxygen leaves the leaf through an opening called the stomata or stoma. The stomata are surrounded by guard cells which control their opening and closing and gas exchange. • The top of the leaf is covered with a waxy substance called a cuticle. It keeps the leaf from losing water when it is hot. Important since photosynthesis needs water. Light Gives off oxygen Glucose Chloroplast 8 This is an elodea plant which is a water plant. When exposed to light little bubbles appear in the water. What are the bubbles? Oxygen...the plant makes it when it is doing photosynthesis from the light. The more light… the more bubbles. The more CO2... the more bubbles. Because, more ingredients = more oxygen (product) Cellular Respiration – this is how cells break down the glucose made in photosynthesis to release energy. All living things do respiration. • Respiration happens in the mitochondria of the cell. This is why we call the mitochondria the power house of the cell because it is releasing energy. The folded inner membrane of mitochondria increases surface area for energy production. Mitochondria use enzymes to help produce energy. • Respiration is the opposite of photosynthesis. • Reactants (ingredients) = glucose and oxygen Products (what you get) =water, carbon dioxide and energy (ATP) C6H12O6 + 6 O2 —> 6 H20 + 6 CO2 + energy 9 (ATP) • There are two types of respiration- Aerobic- respiration that uses oxygen. Makes more energy or 36 ATP. Anaerobic- does not use oxygen (“An” means not). Makes less energy, only 2 ATP. • Another name for Anaerobic respiration is Fermentation. There are two types of anaerobic respiration or Fermentation: Lactic Acid Fermentation- this makes lactic acid. This is the type of respiration our muscles do when they run out of oxygen. It is why our muscles get sore. Bacteria also make lactic acid. Alcohol Fermentation- this is the type of fermentation that is done by yeast. It makes alcohol and can make it from apple juice. If we put apple juice or glucose and yeast into a test tube, the yeast will make alcohol. But it will also make some bubbles. What are the bubbles? Carbon Dioxide which is made as the yeast does alcohol fermentation or anaerobic respiration. Photosynthesis Uses water, light and CO2 Makes Oxygen and glucose Happens in chloroplast Happens in producers Respiration Uses Oxygen and Glucose Makes water, CO2 and energy (ATP) Happens in mitochondria Happens in all living things Has two types: aerobic and anaerobic ATP- is the energy molecule that is made in respiration. It is how our bodies temporarily store the energy made in respiration. 10