Bio Ch. 5,6,7

Briefly describe the 3-D structure of DNA including the base pair rules

DNA is double stranded and the base pair rules are that adenine (purine) always paired with thymine (pyrimidine) and cytosine (pyrimidine) always pairs with guanine (purine)

Compare and Contrast RNA and DNA

DNA: Double stranded has thymine, no uracil present only in nucleus has deoxyribose as sugar RNA: Single stranded has Uracil and no thymine present in both nucleus and cytoplasm has ribose as sugar

Describe the components of a cell membrane in terms of the Fluid-mosaic model

The "fluid" part refers to the phospholipids that can move laterally in the membrane. The "mosaic" part is the proteins that are embedded in the phospholipid bilayer.

Describe what would happen to an animal and plant cell if placed in solutions of various solute concentrations

-Animal cell placed in an isotonic solution will remain normal and water will move back and forth across the cell membrane. If placed in a hypotonic solution, it will burst or lyse as water moves into the cell. If placed in a hypertonic solution, water will leave the cell and the cell will shrivel. -A plant cell in an isotonic solution will be called "flaccid" as water enters and leaves the cell at the same rat. If placed in a hypotonic solution, it will be called "turgid" as the cell wall pushes back against the water pressure and prevents the cell from bursting. In a hypertonic solution, the water will leave the cell, causing it to shrivel and undergo plasmolysis.

Describe what occurs during a general condensation (dehydration) and hydrolysis reaction in the formation and breakdown of polymers

-Condensation reaction or dehydration synthesis: joining of monomers involves one partner losing a -OH group and the other losing a H atom. These join to create a water molecule. Monomers then bond together. -Hydrolysis: Breaking apart of polymers into smaller monomers. Water molecule is added and broken up so that the -OH group goes to one monomer and the H atom to the other.

Compare the following various types of transport across the cell membrane and describe what types of molecules would use each type.

-Diffusion: passive movement of molecules from areas of high to low concentration -Osmosis: Diffusion of water across a selectively permeable membrane, special form of facilitated diffusion. -Facilitated diffusion: Passive movement of molecules from areas of high to low concentration but requires the help of transport proteins to provide a path for polar or charged molecules to move across the hydrophobic core of the cell membrane. -Active transport: Movement of molecules from areas of low to high concentration requiring the use of cellular energy in the form of ATP -Phagocytosis: Cellular "eating" -Pinocytosis: Cellular "drinking" -Receptor mediated endocytosis: More specific form of pinocytosis in which specific receptors on the outside of the cell membrane bind with extracellular ligands to bring them inside the cell

Discuss what determines the 4 levels of protein structure

-Primary: The correct linear order of the amino acid -Secondary: Hydrogen bonds along the polypeptide backbone creating structures such as alpha helixes and pleated sheets -Tertiary: Bonding between R groups further creating 3D shapes of protein -Quaternary: Protein structure gained form aggregation of multiple polypeptide subunits

`Distinguish between prokaryotic cells and eukaryotic cells

-Prokaryotic cells: Simpler; lack membrane bound organelles; still have DNA, ribosomes, plasma membrane and cytoplasm; bacteria, archaea, and cyanobacteria have prokaryotic cells. -Eukaryotic Cells: More complex than prokaryotic; single or multicellular organisms can possess eukaryotic cells (animals, plants, fungi, protists); have many membrane bound specialized organelles for various cell functions

Name the specific monomers in each class of macromolecules and the name of the bonds between them when polymers are formed.

1. Carbohydrates: Monomers-monosaccharides, Bond: glycosidic linkages 2. Lipids: Monomer- Only macromolecules without clear monomer, Bond- Hydrocarbon chains attached to glycerol molecule by ester linkages. 3. Nucleic acids: Monomers-nucleotides, Bond-phosphodeister between sugar and phosphates, hydrogen between 2 strands. 4. Proteins: Monomers-amino acids, Bonds-peptide

Describe the structure of fats, phospholipids, and steroids

1. Fats: 3 hydrophobic hydrocarbon fatty acid chains attached to glycerol 2. Phospholipids: amphipathic with two hydrophobic fatty acids tails attached to glycerol and hydrophilic phosphate head. 3. Steroids: 4 fused carbon ring structures with various attached functional groups

Explain why phospholipids are amphipathic molecules and how this quality contributes to their role in membranes

Amphipathic molecules have parts that are hydrophobic and parts that are hydrophilic. The 2 hydrocarbon tails of phospholipids are composed of chains of carbon atoms noncovalently bonded to hydrogen atoms making the tails hydrophobic. The phosphate group on the phospholipid head is charged making it hydrophilic.

Explain how membrane fluidity is influenced by temperature and membrane composition

As it becomes colder, the phospholipid binary becomes less fluid and more viscous. If the hydrocarbon tails have more unsaturated bonds, it will be more fluid at lower temperatures compared to tails that are more saturated. More cholesterol molecules interspersed through the cell membrane will keep the membrane more fluid at lower temps as well.

Carbohydrates

Carbohydrates (Sugars, composed of C:H:O in a 1:2:1, possess carbonyl groups either as aldehydes or ketons)

List the four major classes of macromolecules and identify their general characteristics

Carbohydrates, Lipids, Nucleic Acids, Proteins

List and describe the major components of all amino acids. Explain how amino acids differ due to the chemical properties of their R groups

Each 20 amino acids have a carboxyl group and an amino group. Each has a unique side chain or R group. The R group can have non-polar, polar or electrically charged qualities.

List conditions under which proteins may be denatured

Extreme high temperatures and other environmental conditions such as variations in pH or salinity. Every protein has optimal environmental conditions that promotes its proper conformation.

Distinguish between hypertonic, hypotonic, and isotonic solutions

In relative comparisons, a hypertonic solution has a higher concentration of solutes to a hypotonic solution. A hypotonic solution would have a lower concentration of solutes compared to a hypertonic solution. Isotonic solutions have equal concentration of solutes to each other.

Lipids

Lipids (Fats, phospholipids, and steroids; composed mostly of carbon and hydrogen with some oxygen, phospholipids and have phosphate groups)

Proteins

Made of amino acids, Amino acids joined together with peptide bonds creating primary structure. Further bonds between amino acids in chain create secondary and tertiary structure important to create 3D structure (conformation) that is necessary for protein to work properly.

Explain the advantages of compartmentalization in eukaryotic cells.

Many of the cell processes need particular environmental conditions to operate properly so keeping these processes separate from the rest of the cell necessary. For example, lysosomes contain digestive enzymes that work at a lower pH than the rest of the cell and need to be separate from the cytoplasm.

Distinguish between mono-, di-, and polysaccharides

Monomers of carbohydrates are monosaccharides. Disaccharides are two monosaccharides joined by a glycosidic linkage. Polysaccharides are long chains of more than 3 monosaccharides each linked by glycosidic linkage.

Nucleic Acids

Nucleic Acids (DNA or RNA; Monomers are nucleotides which are made of a 5 carbon sugar, phosphate group and nitrogenous base; DNA contains genetic information; RNA allows that information to be translated into proteins

List the major components of a nucleotide and describe how these monomers are linked to form a nucleic acid

Nucleotides: 1- 5 carbon sugar (pentose) 2-Phosphate group 3-Nitrogenous base (A, G, C, T, U)

Compare Active and passive transport

Passive transport typically moves molecules from areas of high to low concentration and requires no energy. Active transport moves molecules from areas of low to high concentration, against the concentration gradient and requires energy in the form of ATP.

Distinguish between peripheral and integral membrane proteins. What roles do they play in cell membranes

Peripheral proteins are composed of only hydrophilic regions and are present just on the outside or inside of the membrane. Integral membranes are amphipathic and extend through the cell membrane.

Distinguish between saturated and unsaturated fats

Saturated: No double bonds between hydrogens and carbons in fatty acids. Makes fats more solid at room temp Unsaturated: double bonds present in fatty acids. Makes fats more liquid at room temperature

Explain the role of membrane carbohydrates in cell-cell recognition

Short carbohydrate chains are still attached to the proteins on the outside of the cell membranes. Different cell types and different individuals have unique populations of these carbohydrates which act as ID tags.

Discuss the endomembrane systems and list its members

The endomembrane system is a collection of organelles that possess membranes that may or may not be in continuous contact. Their similar membrane structures allows them to move cellular material from one area to another as processing occurs. Members of the system include: nuclear membrane, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and the plasma membrane

Predict the direction of water movement based on differences in solute concentrations across a membrane

Water will always move down its concentration gradient from areas of high to low concentration. A hypotonic solution has more water than solute compared to a hypertonic solution so water will move form the hypotonic solution into the hypertonic solution