Biology I (2.01-2.03)

Unsaturated Fatty Acid

"Kinked' chains that bend where the double or triple bonds are located on the chain.

Lipids

A type of macromolecule but NOT a polymer because they are not made up of monomers.

Selective Permeability

Allows some substances to pass through but not others.

Cholesterol

An important steroid in our bodies used to make other steroids that we need. Our body builds cholesterol molecules in the liver and we also acquire it from food we eat.

Monomers

Basic building blocks of Polymers.

Monosaccharides

Carbohydrate monomer. • Many types, but the most common are glucose and fructose. • Important energy source for cells. • Carbon atoms in glucose - used to build other important molecules, like fatty acids and amino acids. • If not used immediately, monosaccharides are stored for later use within large molecules.

Cellulose

Carbohydrate polymer made of glucose. Cellulose is a very strong material that serves as the primary structural component of plants. Most animals are not able to break cellulose down into glucose. However, cellulose in the food that we eat is important because it serves as dietary fiber that regulates digestion.

Chitin

Carbohydrate polymer made of glucose. Chitin is another structural polysaccharide made up of glucose molecules. However, it is different than cellulose because it has amino groups (NH2) bonded to the glucose. It is found in the exoskeletons of arthropods such as insects, spiders, lobsters, and crabs. These protective exoskeletons, or anything else made of chitin, cannot be digested by animals.

Glycogen

Carbohydrate polymer made of glucose. Glycogen is the polysaccharide that animals and fungi use to store excess glucose molecules from their food. It serves as an energy reserve that can be broken down into individual glucose molecules when they are needed.

Starch

Carbohydrate polymer made of glucose. Starch is a polysaccharide formed by plants as a way to store the large amounts of glucose produced during photosynthesis. Animals are able to break down starch into individual glucose molecules, which makes starch an important food source.

Polysaccharides

Carbohydrate polymers made up of hundreds to thousands or monosaccharide units. The polysaccharides that are produced and consumed by living organisms, such as starch, cellulose, and glycogen, are all made up of the monomer glucose. • Even though they are all made up of the same monomer, their properties are different because of the differences in how the glucose molecules are arranged in the different polysaccharides.

Cytoplasm & Cytoskeleton

Cytoplasm - Gel-like fluid that fills cell and surrounds organelles. • Location where many reactions in cell occur. Cytoskeleton - A network of fibers, comparable to the bones and muscles of our bodies. • Gives the cell shape, anchors organelles in place, and directs the movement of organelles. (Found in both Plant and Animal cells)

Hydrophobic

Does not dissolve well in water

Nucleus

Easiest organelle to identify - large, dark, and close to the center. • Contains cell's DNA (genetic info). • DNA is packed into chromosomes. • When the cell is not dividing, chromosomes are stringy and entangled called chromatin. (Found in both Plant and Animal cells)

(Concept Questions - 2.01) What are enzymes and how do they regulate chemical reactions?

Enzymes are proteins that increase the rate of a reaction by decreasing the amount of energy needed to start the reaction. They are biological catalysts, molecules of energy needed to start the reaction. Enzymes regulate chemical reactions through changes in speed. Enzymes will make reactions faster and enzyme inhibitors will slow them down.

Fatty Acid

Fatty acids can form fat molecules, but they also serve a number of other important functions in our bodies. Some include controlling inflammation, brain health and development, maintaining fluidity of cell membranes and preventing blood clots.

Chloroplasts

Green in color because they contain the green pigment chlorophyll. Chloroplasts are important because they convert energy from sunlight into chemical energy for the cell > Photosynthesis (Found only in Plant cells)

Steroids

Have 4 linked rings of carbon atoms; some are hormones which control important metabolic processes. (Cholesterol is the most abundant and is also the starting material for most other steroids)

Hydrophilic

Having a strong affinity for water; mixes well with water.

Homeostasis

Homeostasis is a steady balance of conditions inside a system, such as a cell. This balance must be actively maintained, because cells are constantly consuming and producing molecules. As long as cells maintain homeostasis, they can function normally.

Phospholipids

Macromolecule made up of 2 fatty acids and 1 phosphate group bonded to a glycerol. • Phospholipids are similar in structure to fat molecules. Phospholipid: 2 fatty acids + 1 phosphate group bonded to the glycerol

Triglycerides

Macromolecule made up of smaller molecules that include 1 glycerol and 3 fatty acids.

Fat Molecules

Macromolecule made up of smaller molecules that include 1 glycerol and 3 fatty acids. Also called triglycerides due to the 1 glycerol + 3 fatty acids. - Include carbon, hydrogen, and oxygen atoms. • Fats are stored in the body in fat deposits - Serve as stored energy for the organism. • Fat deposits under the skin can provide insulation. • Fat surrounding vital organs provides protection and cushion. Fats, carbohydrates, and proteins all serve as energy sources, but digesting fats releases much more energy than the others. 1 g of fat can provide about 38 kilojoules of energy, compared to 17 kilojoules of energy from 1 g of carbohydrate or protein.

Golgi Apparatus

Made up of stacks of membrane sacs. The Golgi apparatus modifies and stores proteins that are made in the ER. It also sends specialized proteins to parts of the cell as needed. * Protein Post Office * (Found in both Plant and Animal cells)

Vacuoles

Membrane-enclosed sacs that serve many functions: - Store/transport food, water and nutrients that pass through the cell membrane. - Location of breakdown of large molecules. - Plants have one large central vacuole takes up ~80% of the cell's volume. (Found in both Plant and Animal cells)

Nucleotides

Nucleic acid monomer comprised of a nitrogenous base, a 5-carbon sugar, and at least 1 phosphate group. A DNA molecule is actually made up of two nucleotide chains that spiral around an imaginary axis. This shape is called a double helix. A DNA molecule is very long and is made up of hundreds of thousands of genes.

Osmosis

Osmosis is the facilitated diffusion of water using aquaporins. Because the center of a cell's membrane is hydrophobic, it is difficult for water molecules to diffuse directly through phospholipid bilayer.

Explain how passive transport (both diffusion and facilitated diffusion) occurs in cells.

Passive transport is the movement of materials across a cell's membrane without the use of energy by the cell. A cell's cytoplasm is a solution of many different substances dissolved in water. During the process of diffusion, particles move from an area where they are higher in concentration to an area where that substance is lower in concentration. (Facilitated Diffusion) Large hydrophilic molecules cannot diffuse through the cell membrane. Instead, these molecules pass through the membrane with the assistance of proteins that act as channels. The diffusion of molecules through a protein does NOT require energy to be exerted by the cell. Facilitated Diffusion > Passive Transport. In diffusion, particles move from an area where they are higher in concentration to an area where that substance is lower in concentration. In facilitated diffusion, large hydrophilic molecules pass through the phospholipid bilayer of the cell membrane with the assistance of proteins that act as channels for molecules. Osmosis is the facilitated diffusion of water using aquaporins. Because the center of a cell's membrane is hydrophobic, it is difficult for water molecules to diffuse directly through phospholipid bilayer. Aquaporins -specialized proteins that provide a channel through which water can diffuse from an area of higher concentration to an area of lower concentration.

Proteins

Polymer important for nearly every function of a cell. The word protein comes from the Greek word proteios, meaning "first place." • They are used for structure, transporting other substances, storage, signaling from one part of an organism to another, movement, and defense against foreign substances. • Proteins are made up of 50+ amino acids bonded together. A difference of only one amino acid in the protein chain can cause a big difference in the protein's function within a cell.

Nucleic Acids

Polymer of nucleotides bonded together (in a chain) that carries the genetic information needed to build organisms (DNA/RNA). There are two major types of nucleic acids: deoxyribonucleic acids (DNA) and ribonucleic acids (RNA). • DNA contains an organism's genetic information and is usually found within a cell's nucleus. • RNA molecules transport the genetic coding from the DNA to other parts of the cell where proteins are built. • Encoded into the DNA's structure are instructions for constructing a cell and directing all of the cell's activities. DNA and RNA are very important because they allow cells to reproduce their structures from one generation to the next.

(Terms - 2.01) Polymers

Polymers are large molecules composed of many identical or similar subunits called monomers (basic building blocks).

Amino Acids

Protein monomer (There are 20 different amino acids - all share the same basic structure.) • The number and arrangement of amino acids determines the properties and functions of the protein. Every amino acid is made up of a central carbon with four "groups" covalently bonded to it. (Remember that a carbon atom can form 4 single bonds.) The Amino Group is a nitrogen atom with two hydrogen atoms bonded to it. The Carboxylic Acid Group contains a carbon with a double bond to one oxygen atom and a single bond to another; the second oxygen also has a single bond to a hydrogen atom. The Side Chain (represented by the variable "R") is the only part of the molecular structure that varies between the 20 different amino acids that can make up a protein.

Describe the structure of the cell membrane, specifically the phospholipid bilayer.

Selectively permeable - allows some substances to pass through but not others. • Made of carbohydrates, phospholipids, & proteins. Phospholipids make main structure of the membrane. • Arranged in a double layer called the phospholipid bilayer, the hydrophilic ends of each molecule facing outwards on both sides of the cell membrane. Proteins - embedded in the membrane and act as channels or carriers for other molecules. Each protein can only allow a specific type of molecule into the cell. Carbohydrates serve as markers that distinguish one cell from another. For example, the four human blood groups—A, B, AB, and O—have different carbohydrate markers on the surface of their red blood cells. Cholesterol molecules found in the phospholipid layers of the membrane have been found to have an effect on the fluidity, or movement, of the molecules within the membrane

(Terms - 2.02) Organelles

Small organized structures within a cell.

Aquaporins

Specialized proteins that provide a channel through which water can diffuse from an area of higher concentration to an area of lower concentration.

Saturated Fatty Acid

Straight chains which are able to pack tightly together. Because of this, saturated fats require a higher temperature to melt.

Endoplasmic Reticulum

The Endoplasmic Reticulum (ER) is a maze of membranes. • Involved in the cells metabolism. • Makes lipids and proteins. • Breaks down carbohydrates and other harmful substances to the cell. Two types: • Rough = Covered in ribosomes • Smooth = No ribosomes (Found in both Plant and Animal cells)

(HONORS - 2.01) Dehydration Synthesis

The chemical reaction that bonds monomers together to build polymers. During this reaction, water molecules are formed by the atoms that are removed from the monomers.

Hydrolysis

The chemical reaction that breaks down polymers into the smaller monomer units. During this reaction, a water molecule is split in order to replace the hydrogen and oxygen atoms back onto the appropriate monomers.

(Concept Questions (HONORS) - 2.02) What is the endosymbiotic theory?

The endosymbiotic theory hypothesizes that the ancestors of modern day eukaryotic cells were actually 2 or more prokaryotic cells in a symbiotic relationship where one organism lives inside the other, it is called endosymbiosis.

Endocytosis

The membrane forms a pocket around a particle. The pocket then breaks loose from the outer portion of the cell membrane and forms a vesicle within the cytoplasm (enter).

Exocytosis

The membrane of a vesicle surrounds the material then fuses with the cell membrane. The contents are forced out of the cell (exit).

Explain how active transport occurs in cells.

The movement of materials across the membrane that requires energy from the cell. • Requires energy because substances are moving against the concentration gradient (lower concentration to higher concentration). Active transport of small molecules/ions (ex. calcium, potassium, and sodium) is carried out by transport proteins, also called protein "pumps".

Mitochondria

The powerhouse of the cell. They act as the cell's digestive system, taking in and breaking down nutrients. 2 membranes: inner and outer to provide surface area for reactions occur - allows each mitochondrion to do more work. Muscle cells have the most mitochondria because they need the most energy. 22 (Found in both Plant and Animal cells) See: "3 things I learned in High School meme"

Disaccharides

Two carbohydrate monomers bonded together. • Monosaccharides and disaccharides are classified as simple carbohydrates. • Most simple carbohydrates have a sweet taste and are known as "sugars". • Table sugar, called sucrose, is a disaccharide that you use every day.

What evidence supports the theory of endosymbiosis?

Two organelles found inside eukaryotic cells (mitochondria and chloroplasts) have several features in common with whole prokaryotic cells. They contain their own DNA and ribosomes, and are responsible for their own reproduction.

(Terms - 2.03) Cell Membrane

• Selective barrier for cell. • Allows some things to pass into or out of the cell but not others. • Made of phospholipids and proteins (lesson 2.01). • Oxygen and nutrients pass through the cell membrane, and waste products pass out of cell. • Each organelle is surrounded by a selective barrier membrane. (Found in both Plant and Animal cells)

Ribosomes

• Smallest organelles. • Locations for protein synthesis (where proteins are made). Two types: • Free ribosomes are found within the cell's cytoplasm. • Bound ribosomes are attached to another organelle called the Rough Endoplasmic Reticulum. (Found in both Plant and Animal cells)

(Concept Questions - 2.02) Describe the parts of a prokaryotic cell.

- Prokaryotic cells do not have a true nucleus, which means the DNA is not separated from the rest of the contents of the cell. - Enclosed by plasma membranes, filled with cytoplasm, and contain small structures called ribosomes. - Prokaryotic cells have a cell wall - Contain DNA molecules, meaning the genetic coding used in prokaryotic cells is the same as that used in eukaryotic cells. • Smaller and simpler than eukaryotic cells, existing as single-celled organisms. • Prokaryotes do not contain many specialized structures within the cell. In contrast, eukaryotic cells contain dozens of internal structures, called organelles, inside the cell, each of which has specialized functions. • Like all cells, prokaryotes are enclosed by a cell membrane. Outside of the cell membrane, they have a rigid cell wall, similar to a plant cell. Sometimes there is also a jellylike capsule that surrounds the cell wall. Cell Wall - Semi-rigid structures mostly composed of a sugar. The cell wall gives the cell structure and protection. Cell Membrane - Made mostly of fats and proteins that functions to control what comes in and out of the cell. All cells have a membrane. Cytoplasm - A gel-like substance inside the cell where a lot of chemical reactions occur that keep the organism alive. Nucleoid - The area of the prokaryote cell that contains the DNA. Ribosomes - An organelle that is used to make proteins for the cell. Flagella - A long whip like structure used to help the cell move.

Cell Wall

A cell wall surrounds the cell membrane and provides an additional layer of protection for plant cells. • The cell wall maintains the shape of the cell and prevent excess intake or loss of water. • Made mostly of cellulose. (Found only in Plant cells)

Gene

A gene is a section (or subunit) of DNA which represents a molecular unit of heredity and contains instructions for coding a particular protein or for a particular function.