Test 1 Study Guide

Chem Review

  1. Understand atomic structure

    • Atoms are composed of protons (+ charged particles), neutrons (neutral particles), and electrons (- charged particles)

    • Protons and neutrons are in the nucleus

    • Electrons are in the orbitals surrounding the nucleus

  2. Describe how different types of bonding work (ionic, hydrogen, covalent - polar and nonpolar)

    • Differences in electronegativity dictate how electrons are distributed in covalent bonds

      • Electronegativity: a measure of how strongly an atom pulls shared electrons toward itself in a bond

    • Covalent Bond: when two atoms share electrons

    • Hydrogen Bond: an attraction between a hydrogen atom with a partial positive charge and another atom, with a partial negative charge

    • Non-polar covalent bonds: share electrons equally, hydrophobic

    • Polar covalent bonds: don’t share electrons equally, hydrophilic

    • An atom in a molecule with a high electronegativity holds electrons more tightly (partial negative charge), and the other atom will have a partial positive charge

    • Ionic bonds result when electrons are transferred from one atom to another to give both atoms full valence shells

    • An ion is an atom or molecule that carries a charge and comes from polar covalent bonds

      • cation: an atom that loses an electron and becomes positively charged

      • anion: an atom that gains an electron and becomes negatively charged

  3. Explain what makes structures polar and nonpolar

    • Become polar when their atoms have unequal electron sharing due to differences in electronegativity, creating partial positive and negative charges, and the molecules geometry is asymmetric which causes the charge difference to not cancel out

    • Are nonpolar if the atoms share electrons equally (low electronegativity difference) or if the molecule is symmetric and the individual bond polarities cancel each other out

  4. Identify and name the 7 functional groups (table 2.3)

    • Amino: −NH2

    • Carboxyl: —COOH or —CO2H

    • Carbonyl: —C=O

      • aldehydes: R-CHO

      • ketones: R-CO-R’

    • Hydroxyl: —OH

    • Phosphate: —O-P=O-O

    • Sulfhydryl: —SH

  5. Explain the properties of water that make it a great solvent

    • Solvent: any liquid in which one or more solids or gases can dissolve

    • Water’s small size, highly polar covalent bonds, and bent shape resulting in overall polarity are unique

    • Has covalent OH polar bonds

Cell Parts

  1. Compare and contrast eukaryotic and prokaryotic cells

    • Prokaryotic Cells: absence of a membrane-bound nucleus and lacks membrane bound organelles

      • characteristics include a plasma membrane, at least one chromosome, many protein-synthesizing ribosomes enclosed within a plasma membrane

    • Eukaryotic Cells: presence of a membrane-bound nucleus that contains the cells genetic material (DNA) and other membrane-bound organelles like the mitochondria, endoplasmic reticulum; building blocks for complex organisms including plants, animals, fungi, and protists

    • Similarities: have DNA, cell or plasma membrane, cytoplasm, ribosomes

    • Differences: cell size, cell structure, organization, DNA structure, DNA location, cell division, ribosome size, cytoskeleton, reproduction

  2. Compare and contrast animal and plant cells

    • Plant and animal cells are both eukaryotic cells

    • Similarities: have nucleus, cell membrane, cytoplasm, mitochondria, endoplasmic reticulum, Golgi apparatus, ribosomes, peroxisomes

    • Differences:

      • cell wall - plant cells have a rigid outer layer made of cellulose that surrounds the cell membrane which provides structural support while animal cells do not have a cell wall and the cells are contained by a flexible membrane

      • chloroplasts - present in plant cells since it is the site of photosynthesis, but it is absent in animal cells since they obtain energy from consuming other organisms

      • vacuoles - plant cells have a large central vacuole that stores water, nutrients, waste, maintains turgor pressure to keep the cell rigid where animal cells have numerous small and temporary vacuoles which are involved in removal and transport instead

      • storage - plant cells store carbohydrates as starch and animal cells store carbohydrates as glycogen

      • shape - plant cells have a fixed rectangular or cubic shape due to the rigid wall where animal cells have an irregular or round shape giving them more flexibility

  3. Provide a brief description for each of the organelles and parts of the eukaryotic and prokaryotic cells (7.2)

    • Eukaryotic Cell

      • nucleus: information storage and transmission, ribosome subunit assembly, structural support

      • ribosomes: protein synthesis

      • endomembrane system: smooth ER, rough ER, Golgi apparatus, lysosomes

      • rough endoplasmic reticulum: protein synthesis and processing

      • smooth endoplasmic reticulum: lipid synthesis and processing

      • Golgi apparatus: protein, lipid, and carbohydrate processing

      • lysosomes: digestion and recycling

      • vacuoles: digestion and recycling

      • peroxisomes: oxidation of fatty acids, ethanol, or other compounds

      • mitochondria: ATP production

      • chloroplasts: production of sugars via photosynthesis

      • cytoskeleton: structural support, movement of materials, in some species movement of whole cell

      • plasma membrane: selective permeability, maintains intracellular environment

      • cell wall and extracellular matrix: protection, structural support

    • Prokaryotic Cell

      • nucleoid: central region of the cell that contains the single circular chromosome of DNA

      • ribosomes: sites of protein synthesis, responsible for translating mRNA into proteins, floating freely in the cytoplasm

      • cytoplasm: site for many metabolic reactions, jelly-like substance that fills the cell and holds all the other components

      • cell membrane: outer covering separates the cells interior from the outside environment and regulates what enters and exists the cell

      • cell wall: rigid layer outside the cell membrane that provides structural support, protects the cell from the mechanical damage and helps maintain its shape

      • capsule, flagella, pili, plasmids

  4. Identify the organelles of a cell in different models or pictures

  1. Explain how the relative amounts of organelles can indicate function of the cell

    • Cells that perform a certain task at a high volume will possess a greater abundance or a larger size of the organelle responsible for that task

Carbohydrates

  1. Know the building blocks for carbohydrates

    • Monosaccharides: simple sugars and monomers of carbohydrates

      • vary in carbon count (either 3, 5, 6)

      • vary in spatial arrangement of atoms

      • monosaccharide (one monomer), oligosaccharide (small polymers), polysaccharide (many large polymers)

  2. Identify the structure of carbohydrates

    • (CH2O)n

    • Carbonyl group that serves as one of the monosaccharides is either at the end of the molecule forming an aldehyde/aldose or within the carbon chain forming a ketone/ketose (C=O)

    • Contain carbonyl group (C=O), hydroxyl group (O—H), carbon-hydrogen bonds (C-H)

      • carbonyl and hydroxyl groups are polar, carbohydrates are hydrophilic

    • Points on structures are carbon (know for images on test)

  3. Nam the type of linkage associated with carbohydrates

    • Glycosidic linkages: a covalent bond formed by a condensation reaction between two sugar monomers; joins the resides of a polysaccharide

      • connects monomers together

      • forms between hydroxyl groups

      • a-linkage —» energy molecule

      • b-linkage —» structural molecule

  4. Identify the polysaccharides and their functions in various organisms

    • Starch: a-glucose monomers, to store energy in plants

    • Glycogen: composed of glucose monomers joined by a-1,4 and a-1,6 glycosidic linkages; major form of stored carbohydrates in animals

    • Cellulose: composed of glucose monomers joined by b-1,4 glycosidic linkages; found in the cell wall of algae, plants, and some bacteria of fungi

    • Chitin: composed of N-acetly-glucosamine (NAG) monomers joined end to end by b-1,4 glycosidic linkages; found in cell walls of fungi and many algae, and in external skeletons of insects and crustaceans; structural and protective function

    • Peptidoglycan: found in bacterial cell walls; provides structural support, rigidity, and protection to the cell

    • Similarity between starch and cellulose: both made of glucose

    • Difference between starch and cellulose: starch has a-linkages while cellulose has b-linkages, starch is a helix molecule while cellulose is linear composed of parallel strands with hydrogen bonds

  5. Compare and contrast the polysaccharides from table 5.1

Lipids

  1. Know the building blocks for lipids

    • Fatty acids and glycerol

      • fatty acids are long chains of carbon atoms

      • glycerol is a three-carbon alcohol molecule with 3 hydroxyl groups

  2. Name the type of linkage associated with lipids

    • Ester linkage

      • Adding a fatty acid through dehydration reaction makes a triglyceride (stores energy) which makes an ester linkage and a carbonyl

  3. Understand the reaction that attaches building blocks to the macromolecules and how it can be reversed

    • Dehydration synthesis/condensation reaction

      • monomers polymerize through this

      • a chemical reaction in which two molecules are joined covalently with the removal of an —OH from one and an —H from another to form water

    • Hydrolysis

      • a chemical reaction in which a molecule is split into smaller molecules by reacting with water, most involve splitting of polymers into monomers

        • adding a water molecule

        • water molecule reacts with the bond linking the monomers separating one monomer from the polymer chain

  4. Be able to explain how the number of carbons and type of bonds within the fatty acid affect the characteristic of the lipid

  5. Identify the different types of lipids and functions in the cell

    • Steroids, Fats, Phospholipids

      • don’t polymerize or make chains

      • characteristic: non-polar or hydrophobic and have hydrocarbons

    • Steroids

      • distinguished by a 4 fused ring carbon skeleton, attached to carbons in the ring

    • Fats

      • composed of three fatty acids linked to a glycerol molecule, also called triglycerides, primary role is to store energy, form by a dehydration reaction (a hydroxyl group of glycerol and the carboxyl group of a fatty acid), glycerol and fatty acid molecules become joined by an ester linkage

    • Phospholipids

      • consist of a glycerol linked to two fatty acid tails and a phosphate group with an ester linkage

        • hydrophilic head that contains glycerol and a hydrophobic tail that is composed of two non-polar fatty acids

      • in bacteria and eukarya, isoprenoids in archaea

      • primary role is to form a lipid bilayer of all cell membranes which creates a protective semi-permeable barrier that regulates the passage of substances into and out of the cell

  6. Explain the amphipathic nature of phospholipids

    • when amphipathic lipids are placed in water the hydrophilic heads interact with water, the hydrophobic tails interact with each other away from the water

      • forms lipid micelles and lipid bilayers

  7. Discuss which types of molecule would be permeable through the lipid membrane

  8. Explain the factors that can alter membrane permeability

  9. Know the structure of cholesterol and how it impacts both permeability and fluidity

  10. Explain the setup and the trends associated with figure 6.10