Bio

What characteristics are used to determine whether something is alive or not?

What characteristics are used to determine whether something is alive or not?

Composed of cells, highly organized, grow and develop, reproduce, maintain homeostasis, respond to stimuli, use/need energy and metabolize, evolve over time, and based on a genetic code.

Are viruses living or not?

Viruses are not alive because they do not meet all the criteria to be considered a living thing. Viruses have a genetic code that they pass to other healthy cells in your body, but they cannot reproduce without transmitting their DNA to other cells. Viruses do not maintain homeostasis and have no way to metabolize and use energy. They also aren't composed of cells by themselves, but infect other cells and grow and develop as they reproduce. Since viruses meet very few of the criteria, they are not alive.

Describe the term matter.

Matter is anything that occupies space, has mass, and is made up of elements.

What is the difference between an element and a compound?

An element is a substance made up of only one type of atom that cannot be broken down into simpler chemical substances. A compound is a substance composed of atoms of two or more elements in a new combination in a fixed ratio. They have different characteristics than the element alone.

What are the 6 most common elements in living things?

Carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus.

What are trace elements and why are they important?

Trace elements are elements that are needed by organisms, but only in small amounts. They are important because they all have specific roles that help the organism.

What are the three components of an atom and what are their charges?

Proton - positive charge, neutron - no charge, electron - negative charge.

What is the difference between an atom's atomic number and its mass number

The atomic number is the number of protons in an atom and an atom's mass number is the number of protons and neutrons.

Define the terms isotope and ion.

An isotope is the same type of atom, but they have different numbers of neutrons. An ion is an atom or molecule with an electrical charge from gaining or losing electrons.

What makes an isotope radioactive?

An isotope is radioactive when its nucleus decays spontaneously and gives off energy and particles.

What is the difference between a polar covalent molecule and a nonpolar covalent molecule?

A polar covalent bond occurs when two atoms share electrons unequally. A nonpolar covalent bond occurs when two atoms share electrons equally.

Explain how electronegativity relates to the formation of polar and nonpolar covalent bonds.

When two atoms have a very similar electronegativity, they form a nonpolar covalent bond and share the electrons equally. When two atoms have very different electronegativities, they form a polar covalent bond and the electrons are pulled closer to the more electronegative atom.

Summarize what happens during a chemical reaction.

A chemical reaction is the breaking and making of chemical bonds. The reactants (starting materials) get reacted on and turn into products (materials resulting from the reaction).

What are the components of a chemical equation?

Reactants and products.

During a chemical reaction, is matter created or destroyed?

Matter is neither created nor destroyed during a chemical reaction, it is simply rearranged.

Why is a water molecule considered to be polar covalent?

Water molecules are polar covalent because the electrons are shared unequally between the hydrogen atoms and the oxygen atom. Oxygen is more negatively charged than hydrogen, so it pulls the electrons towards it more than the hydrogens.

Water molecules bond to one another using hydrogen bonding. What does this look like at the molecular level and why does it happen this way?

Hydrogen bonds are bonds between two water molecules between the slightly positive hydrogen atom of one water molecule and the slightly negative oxygen atom of another water molecule. It happens this way because, in a water molecule, the bond between the hydrogen atoms and oxygen atom is polar covalent, which makes the oxygen molecule slightly negative and the hydrogens slightly positive.

What is the difference between adhesion and cohesion?

Adhesion occurs when water sticks to other substances and cohesion occurs when water sticks to other water molecules.

How are adhesion and cohesion used by organisms to sustain life?

Organisms use cohesion in many different ways. Water striders use cohesion to walk on top of the water. They are light enough that they don't break the hydrogen bonds on the top of the water. Adhesion is used by trees to drink water up from their roots against the force of gravity.

Explain how surface tension is related to cohesion.

Surface tension measures how difficult it is to stretch or break the surface of a liquid. It is related to cohesion because it happens when two molecules of the same substance stick together to create tension.

What is capillary action? Describe its connection to cohesion and adhesion.

Capillary action is the ability of a liquid to flow up against gravity up a narrow space. It uses adhesion and cohesion to occur. The liquid sticks to the sides of the narrow space (adhesion) and sticks to each other inside the narrow space (cohesion) to move up against gravity.

How is water able to resist changes in temperature compared to most other substances?

It is able to resist temperature changes due to hydrogen bonding. Heat is absorbed when hydrogen bonds break and heat is released when hydrogen bonds form. This prevents sudden changes in temperature.

Explain why/how ice has a lower density than liquid water.

The molecules and hydrogen bonds are further apart and they pull on each other when water freezes.

Define the terms solute, solvent, and aqueous solution.

A solute is a substance that is being dissolved. A solvent is a substance that is doing the dissolving. An aqueous solution is a solution where water is the solvent.

What is the difference between an acid and a base?

An acid is any compound that forms hydrogen ions in a solution. A base is any compound that forms hydroxide ions in the solution.

How do acids and bases directly (or indirectly) affect the hydrogen ion concentration of a solution?

Acids increase the hydrogen ion concentration of a solution and bases decrease the hydrogen ion concentration of a solution.

Explain the basis for the pH scale.

The pH scale is the scale that measures how basic or acidic a solution is.

What is a buffer and why is it important?

A buffer is important because it keeps your body from changing (balanced). It is a substance that prevents sharp changes in pH.

What are organic molecules?

Carbon-based molecules

What makes carbon so versatile as the atom of choice for the creation of macromolecules like carbohydrates, lipids, and proteins?

Carbon can bond with 4 other atoms. It can also bond to other carbon atoms to make a variety of carbon skeletons.

Differentiate between monomers and polymers. Create an analogy to represent the connection between both.

Polymers are made up of monomers. Polymers are long chains formed by linking monomers together. A monomer to a polymer is like a brick to an entire brick wall.

Describe what happens during a dehydration reaction and for what purpose. How is water involved?

Dehydration is the building of macromolecules. During dehydration, water is taken away from the chain and another monomer is added to the chain.

Describe what happens during a hydrolysis reaction and for what purpose. How is water involved?

Hydrolysis is the breakdown of macromolecules. During hydrolysis, water is added to the chain and the monomers are broken apart.

Name the elements of carbohydrates and identify the monomers of this macromolecule.

Carbohydrates contain carbon, hydrogen, and oxygen in a fixed 1:2:1 ratio (C1H2O1). Their monomers are monosaccharides.

List and briefly describe the 2 major functions of carbohydrates.

Carbohydrates are a source of energy for organisms and are used for structural purposes in plants.

Describe the relationship among monosaccharides, disaccharides, and polysaccharides.

Monosaccharides are simple sugars made up of a single sugar unit. Disaccharides are double sugars made up of 2 monosaccharides. Polysaccharides are complex sugars made up of many monosaccharides linked together.

Compare and contrast the 3 major polysaccharides with regards to structure, function, and which organism(s) they are found in.

Starch is made entirely of glucose monomers linked in a straight chain. They are only found in plant cells and they are sugar stockpiles. Glycogen is made entirely of glucose monomers but is more highly branched. They are found in only animal cells and they store sugar in them. Cellulose is made entirely of glucose monomers and it is multiple chains linked, forming a cable-like structure. They are mainly found in plant cells and they serve as a building material and protect the cell.

Name the elements of lipids and identify the monomers of this macromolecule.

Lipids are made up of carbon, hydrogen, and oxygen. The monomers of lipids are triglycerides. They are a 3 carbon backbone with 3 fatty acid tails.

Explain why water and lipids do not freely mix.

Lipids are hydrophobic, which means they are water "fearing."

Describe the basic structures of fats and triglycerides.

Triglycerides, the monomers of fats, are made up of a 3 carbon backbone with 3 fatty acid tails.

List the 3 major functions of lipids.

They are a major component of biological membranes, they are used to store energy, and they make waterproof coverings on plants.

Compare and contrast saturated fats and unsaturated fats.

Saturated fats contain the maximum number of hydrogen atoms and are solid at room temperature. Unsaturated fats contain a double bond between two carbons in the backbone and are liquid at room temperature.

Explain the health consequences involved with consuming trans fatty acids and utilizing anabolic steroids.

Trans fatty acids are hydrogenated, which means they are unsaturated fats turned to saturated fats by adding hydrogen. These types of fats can be bad for your heart health if consumed too much. Anabolic steroids are manufactured testosterone that enhances performance in humans. These can lead to cancer, liver and kidney failure, and death if they are abused.

Name the elements of proteins and identify the monomers of this macromolecule.

Proteins are made up of carbon, hydrogen, oxygen, and nitrogen. The monomers of this macromolecule are amino acids.

What are the 4 major functions of proteins?

Structural, a major component of muscles, transportation, and communication.

What is the basic structure of an amino acid and explain how the "R" group differentiates amino acids from one another.

An amino group, a carboxyl group, an H group, and an R group. The "R" group is different from each amino acid, and it determines what the amino acid can bond to.

What is a polypeptide, what type of reaction helps build this molecule, and what type of reaction helps break this molecule?

A polypeptide is a chain of amino acids linked together by peptide bonds. A dehydration reaction helps build this molecule and a hydrolysis reaction helps break this molecule.

Explain the importance of a protein's shape to its function.

A protein's shape determines which molecules the protein binds to so they can function. Shape determines function.

What is denaturation and explain the consequences of denaturation on the function of proteins?

Denaturation is the process where a protein unravels and loses its shape and function. This can be dangerous because if a protein loses its shape, it also loses its function, which can affect your cells and your body as a whole.

Justify the importance of a protein's primary structure to all further levels.

The primary structure is incredibly important because it is the base of the other structures. If the sequence of amino acids in the primary structure is wrong then the rest of the levels cannot form.

What does it mean to say that an enzyme is a catalyst?

An enzyme is a catalyst, meaning that it is a compound that speeds up a chemical reaction.

Explain how enzymes speed up activation energy.

Enzymes speed up reactions by lowering the activation energy needed to start the reaction so they can occur at a cell's normal temperature.

Describe how an enzyme functions (catalytic cycle).

1. The substrate (the thing being acted upon) enters the active site (the region on the enzyme where the substrate fits), 2. The active site changes shape to form an induced fit on the substrate, 3. The substrates are converted to products, 4. The products are released.

What is meant by the term induced fit in connection to enzymes?

Induced fit is when an enzyme's active site changes shape and folds around the substrate in the active site.

How can changes in pH and temperature affect enzyme activity?

Enzymes are most productive under specific conditions. If you change the pH or temperature of the environment around the enzyme, the enzyme won't work as well or won't work at all.

What is an inhibitor?

An inhibitor is a chemical that interferes with an enzyme's activity.

Differentiate between competitive inhibition and non-competitive inhibition.

A competitive inhibitor binds to the active site of an enzyme and blocks substrates from entering and getting acted upon. A noncompetitive inhibitor binds to some other place on the enzyme and changes the shape of the active site so that substrates can no longer fit.

Give an example of how drugs, pesticides, or medicine act as enzyme inhibitors.

Drugs: inhibits enzymes involved in the release of pain in response to an injury (reduces pain). Pesticides: developed by humans for agriculture, landscaping, and warfare purposes. Medicine: inhibits enzymes that promote the cell division of disease-causing bacteria.

Why are cells so small?

Cells' surface area to volume ratio is small because the surface area needs to be big enough to service the volume. It also must be big enough so materials can pass through the membrane and carry out processes efficiently.

How is a light microscope different from an electron microscope?

A light microscope uses visible light that passes through a specimen and then through a glass lens. An electron microscope uses electrons that bounce off the specimen and project an image.

List 3 components of the cell theory.

1. all cells come from preexisting cells, 2) all living things are made up of cells, 3) cells are the basic units of structure and function in living things.

Who are Robert Hooke and Anton van Leeuwenhoek and how are they connected to cells?

Robert Hooke was a scientist that first discovered cells by observing a thin slice of cork. AvL discovered bacteria by observing a pond water sample.

Define, and also compare and contrast, prokaryotic and eukaryotic cells.

Prokaryotic cells are cells that have no nucleus and no membrane-bound organelles. They are simpler and smaller in size. An example is bacteria. Eukaryotic cells are cells that have a nucleus and membrane-bound organelles. They are more complex and bigger in size. Examples are plant, animal, and protist cells.

Identify the major structures of prokaryotes that are unique to their cellular form (capsule, pilus, flagellum, plasmid) and describe the functions of these structures.

Capsule (slime layer): sticky capsule around the cell that enhances bacteria to cause disease. Pilus: extensions of the plasma membrane that help bacteria stick to other surfaces and serve as a bridge for the exchange of DNA. Flagellum: whip-like projection used for movement (like a tail). Plasmid: genes separate from chromosomes that carry antibiotic-resistant genes.

How are prokaryotes both helpful and harmful?

Helpful: they decompose organic matter to help form soil, help with digestion, help make nitrogen available for organisms, and help make certain foods, Harmful: They are capable of causing certain diseases due to lack of hygiene.

What is an organelle?

A membrane-bound subcellular structure that has one or more specific jobs to perform in a cell.

Outline the similarities and differences between plant and animal cells.

Plant cells: cell wall, one single vacuole, chloroplasts, rectangular shape, plasmodesma. Animal cells: lysosomes, centrosome with a pair of centrioles, small vacuoles, organic shape.

Describe the structure and function of the following: nucleus, rough ER, Golgi apparatus, lysosome, vacuole, vesicle, chloroplast, mitochondria, cytoskeleton, centrioles, cell wall.

Nucleus: control center, rough ER: transport materials and ribosomes on it, Golgi apparatus: package and shipping of materials throughout the cell, lysosome: collection of waste products, vacuole: storage place for food and water, vesicle: transport materials around the cell, chloroplast: provide chlorophyll for plant cells, mitochondria: powers the cell and provides ATP, cytoskeleton: the internal framework that helps cell keep its shape, centrioles: separate chromosomes to help with cell division, cell wall: regulate what goes in and out and protects the cell.

Describe the pathway of protein manufacture between a ribosome and the cell membrane.

Once the ribosomes produce the proteins, they travel through the rough endoplasmic reticulum into a vesicle where they are taken to the Golgi apparatus where they are packaged. They then enter another vesicle that takes them to the cell membrane, where it then leaves the cell with the help of energy from the mitochondria.

Identify the 2 major functions of the cell membrane.

They protect the cell from water, and transport materials in and out, and regulate what enters and exits.

Discuss why the cell membrane is described as a fluid mosaic model.

It is described that way because it has a lot of different things that make it up.

Define the terms hydrophilic and hydrophobic.

Hydrophilic means attracted to water ("water-loving"), and hydrophobic means repelled by water ("water-fearing").

What is the function of cholesterol in cell membranes?

Cholesterol sits in between the phospholipids and keeps them from bunching up.

List the functions of membrane proteins.

They send signals, are used for cell-to-cell recognition, transport materials across the membrane, and carry out chemical reactions.

Why is the cell membrane described as being selectively permeable and what types of items can cross and which ones cannot?

The cell membrane is selectively permeable because it only allows certain substances to pass through it. Non-polar molecules can pass through the membrane with ease, but polar molecules (except water) and ions need assistance.

Define the term concentration gradient.

The difference in the concentration of a substance between two areas. Particles follow a natural pattern when moving across a membrane.

Connect the terms solution, solute, and solvent.

A solute is a substance that is being dissolved. A solvent is a substance that does the dissolving. The solution is a mixture of 2 or more substances that are evenly distributed.

What is diffusion?

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration to find equilibrium.

How is active transport different from passive transport?

Active transport requires energy to occur and passive transport does not require energy.

What is osmosis?

Osmosis refers to the movement of water along the concentration gradient.

How does osmosis affect cells placed in the following solutions - hypertonic, hypotonic, and isotonic?

When cells are placed in a hypertonic solution and the concentration of the solute is greater outside the cell than inside, water will leave the cell to find equilibrium. This will cause the cell to shrink and shrivel. When cells are placed in a hypotonic solution and the concentration of the solute is greater inside the cell than outside, water will enter the cell from the outside to find equilibrium. This will cause the cell to expand and swell. When cells are placed in an isotonic solution and the concentration of the solute is equal on both sides of the membrane, no net osmosis will occur and nothing will happen to the cell.

How does osmosis affect plant and animal cells differently?

Osmosis only affects the cell membrane. In animal cells, the membrane will swell or shrink and cause the cell to swell or shrink. In plant cells, the membrane will swell or shrink, but the shape of the cell wall will not change, so the cell will keep its shape.

Differentiate between facilitated diffusion and active transport.

Facilitated diffusion involves the movement of materials through the membrane using carrier and channel proteins, and it follows the natural concentration gradient. It does not require energy. Active transport involves the movement of materials through the membrane using carrier and channel proteins, but it goes against the concentration gradient. It also requires ATP to occur.

How do endocytosis and exocytosis differ from one another and how do phagocytosis and pinocytosis differ from one another?

Endocytosis is the bringing in of materials and exocytosis is the releasing of materials. Phagocytosis occurs when the cell brings in food particles (cell eating) and pinocytosis occurs when the cell brings in liquid particles (cell drinking).

Define homeostasis and discuss the importance to cells.

Homeostasis refers to the dynamic state of steady internal, physical, and chemical conditions maintained by living systems. It is important because it helps the cell maintain its normal internal environment to help it keep functioning.

Outline the discovery of aquaporins and specify their connection to the process of osmosis.

Water can diffuse rapidly through the cell membrane due to aquaporins. They were discovered by Dr. Peter Agre. The discovery of facilitated diffusion led to this discovery.

Define the term energy.

The ability to do work and cause change. It allows your body to perform its daily functions.

Differentiate between kinetic and potential energy.

Potential energy is the energy stored in the location or structure of matter, and it includes chemical energy (energy stored in bonds). Kinetic energy is the energy of motion.

Describe food energy in terms of potential and chemical energy.

Most organisms obtain their energy from food. Autotrophs obtain it from the sugars they create (plants), and heterotrophs obtain it from the food they consume (animals).

How are the 1st and 2nd Laws of Thermodynamics different from one another?

The 1st law of thermodynamics states that energy cannot be created or destroyed. The 2nd law of thermodynamics states that the amount of energy available for use decreases as it transfers, which leads to an increase in disorder; some energy is lost as heat.

How do exergonic and endergonic reactions differ?

Exergonic reactions involve energy being released and endergonic reactions involve energy being stored.

What is meant by the concept of energy coupling?

The use of energy released from an exergonic reaction drives an essential endergonic reaction.

What is ATP and describe its structure.

Energy currency of cells that powers its activity. ATP has a nitrogenous base called adenine, a 5-carbon sugar called ribose, and a triphosphate group.

How is the energy of ATP stored? How is it released?

Energy is stored through phosphorylation. A 3rd phosphate group is added to ADP to create ATP and energy is stored in the bond between the phosphates. Energy is released when the bond between the 2nd and 3rd phosphate in ATP is broken and ATP is converted to ADP.

List and briefly describe the 3 types of cellular work.

Chemical: phosphorylation

Mechanical: contraction of muscle cells

Transport: active transport.

Describe the ATP cycle (cellular respiration).

It starts in the cytoplasm with glycolysis. A glucose molecule and 2 ATP are needed to start the reaction. Glycolysis breaks down the glucose into 2 pyruvate molecules and charges 2 NAD+ by adding hydrogen and making it NADH to aid in the electron transport chain. This produces 4 ATP molecules for a net increase of 2 ATP. Then, if there is oxygen present, the 2 pyruvate molecules move to the Krebs Cycle in the mitochondrial matrix. There, the pyruvate is further broken down to charge more NAD+ and FAD molecules. Carbon dioxide is created as a byproduct of this stage, which we then exhale. 2 ATP molecules are produced from the Krebs Cycle. Then, the charged NADH and FADH2 move to the electron transport chain in the mitochondrial cristae, which generates ATP from the charged NADH and FADH2. When the hydrogen atoms are released, oxygen is the final acceptor of them, and they bond to create water. 32-34 ATP molecules are produced.

What is cellular respiration?

Cellular respiration is the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.

Write and label the overall balanced chemical equation for cellular respiration.

Glucose (C6H12O6, consumed food) + 6 Oxygen (O2, breathing in) → 6 Carbon dioxide (CO2, Krebs Cycle, and exhaled) + 6 Water (H2O, Electron transport chain, exhaled) + Energy (ATP, generated in all 3 steps)