Biology EOC Review Packet Notes

Nucleic Acids

  • Two types:
    • Deoxyribonucleic Acid (DNA)
    • Ribonucleic Acid (RNA)

Comparing DNA & RNA

  • Both contain Cytosine (C), Adenine (A), and Guanine (G)
  • DNA:
    • Sugar: Deoxyribose
    • Structure: Generally Double-stranded (Double helix)
    • Nitrogen Base: Thymine (T)
  • RNA:
    • Sugar: Ribose
    • Structure: Generally Single-stranded
    • Nitrogen Base: Uracil (U)

Complementary Bases

  • DNA:
    • Adenine (A) bonds with Thymine (T)
    • Guanine (G) bonds with Cytosine (C)
  • RNA:
    • Adenine (A) bonds with Uracil (U)
    • Guanine (G) bonds with Cytosine (C)
  • Bonding occurs via Hydrogen Bonds.

Biochemical Reactions

  • Allow organisms to grow, develop, reproduce, and adapt.
  • Factors affecting reaction rates:
    • Changes in temperature (gaining or losing heat energy)
    • pH (measure of acidity)

Enzymes

  • Proteins that serve as catalysts in living organisms.
  • Increase enzyme activity.
  • Very specific: each enzyme catalyzes one chemical reaction on one particular substrate.
  • Examples: digestion, respiration, reproduction, movement, cell regulation.
  • Structure altered by temperature and pH.
  • Typically end in "-ase".

Catalysts

  • Substance that changes the rate of a chemical reaction or allows it to occur at a lower temperature.
  • Each catalyst works best at a specific temperature and pH.
  • Lower the activation energy of a chemical reaction.
  • Can be used repeatedly.

Enzyme-Substrate Interaction

  • Substrate enters the active site of the enzyme.
  • Enzyme changes shape slightly as substrate binds, forming an enzyme/substrate complex.
  • Enzyme/products complex is formed.
  • Products leave the active site of the enzyme.

Enzyme Activity and Energy

  • Enzymes lower the activation energy required for a reaction.
  • Optimal temperature range for enzyme activity, beyond which activity decreases.
  • Optimum pH for enzyme activity.

Macromolecules

  • All organisms are composed of organic molecules containing Carbon atoms.
  • Made of smaller units that bond to form larger molecules.
  • Energy is stored in the bonds that link these units together; the amount varies with the type of molecule formed.

Types of Macromolecules

Carbohydrates

  • Elements: Carbon, Hydrogen, and Oxygen.
  • Monomer: Monosaccharide
  • Examples: Sugars and starches.
  • Functions: Provides energy to cells, stores energy, and forms body structures.

Lipids

  • Elements: Carbon, Hydrogen, and Oxygen.
  • Monomer: None specified in the text.
  • Examples: Fats and oils.
  • Functions: Stores energy, forms cell membranes, and carries messages.

Proteins

  • Elements: Carbon, Hydrogen, Oxygen, Nitrogen, and Sulfur.
  • Monomer: Amino Acid
  • Examples: Enzymes and antibodies.
  • Functions: Helps cells keep their shape, makes up muscles, speeds up chemical reactions, carries messages and materials.

Nucleic Acids

  • Elements: Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorus.
  • Monomer: Nucleotide
  • Examples: DNA and RNA.
  • Functions: Contains instructions for proteins, passes instructions from parents to offspring, and helps make proteins.

Carbohydrates (Sugars and Starches)

  • Composed of Carbon, Hydrogen, and Oxygen.
  • Basic carbohydrates are simple sugars (glucose).
  • Simple sugars bind together to make starch, glycogen, or cellulose.
  • Important energy source for all organisms; stores energy for short periods.
  • Some (like cellulose) are used as structural material in plants.

Lipids

  • Composed of Carbon, Hydrogen, and Oxygen that often bond to form Fatty Acids and Glycerols.
  • Have more C-H bonds than carbohydrates, thus containing more energy per gram.
  • Provide long-term energy storage, cushioning of vital organs, and insulation for the body.
  • Insoluble in water.

Phospholipids

  • Major component of cell membranes.
  • Phosphate group/head (Hydrophilic - water liking).
  • Fatty acid tail (Hydrophobic - water fearing).

Proteins

  • Composed of chains of Amino Acids (C, H, O, N, and sometimes S).
  • Involved in almost every function in the human body.
  • Enzymatic proteins speed up chemical reactions and enzymes can be reused.

Nucleic Acids

  • Organic molecules that carry and transmit genetic information; made of Nucleotides.

Nucleotides

  • Have three parts:
    • A nitrogenous base.
    • A simple (pentose) sugar.
    • A phosphate group

Prokaryotic vs. Eukaryotic Cells

Prokaryotic Cells

  • Do NOT have a nucleus.
  • DNA is in the cytoplasm in the form of circular chromosomes.
  • Lack all organelles except ribosomes, cytoplasm, and a cell membrane.
  • Most are unicellular.

Eukaryotic Cells

  • Have a nucleus.
  • DNA is in the nucleus in the form of linear chromosomes.
  • Contain organelles.
  • Can be unicellular or multicellular.

Eukaryotic Cells

  • Have specialized Organelles that carry out the essential functions of life

Nucleus

  • Contains the chromosomes composed of DNA and functions in the genetic control of the cell.

Cytoskeleton

  • A network of fibrous proteins that helps the cell with maintaining shape, support, and movement.

Endoplasmic Reticulum (ER)

  • A complex, extensive network that transports materials throughout the inside of a cell.
    • Rough ER: Has ribosomes attached to the surface.
    • Smooth ER: Has no ribosomes attached to the surface.

Ribosomes

  • The sites of protein synthesis; some are located on the ER, others are found in the cytoplasm.

Golgi Complex

  • Collects, packages, and otherwise modifies cell products (for example proteins and lipids) for distribution and use within or outside the cell.

Vesicles

  • Carries proteins from the rough ER to the Golgi apparatus.

Mitochondria

  • Are the sites of cellular respiration, a process which supplies the cell with energy.

Chloroplasts

  • Are found only in plant cells.
  • Contain the green pigment, Chlorophyll, which absorbs energy from the Sun to convert carbon dioxide and water into sugar through the process of photosynthesis.

Lysosomes

  • Contain chemicals called Enzymes necessary for digesting certain materials in the cell.

Vacuoles

  • Store materials such as water, salts, proteins, and carbohydrates.
  • Vacuoles in animal cells (if they are present) are much smaller than those in plant cells.

Cell Membrane

  • Encloses the cell and regulates the passage of materials between the cell and its environment.
  • Aids in protection and support of the cell.

Cell Wall

  • Is the cell structure that surrounds the cell membrane for protection and support in plant cells, bacteria, fungi, and some protists, and allows for specific substances to pass in and out of the cell.

Cytoplasm

  • Is the semi-fluid material inside the cell containing molecules and the organelles, exclusive of the nucleus; is bound by the cell membrane.

Plant Cell

  • Nucleus
    • Nuclear envelope: membrane enclosing the nucleus. Protein-lined pores allow material to move in and out.
    • Chromatin: DNA plus associated proteins.
    • Nucleolus: condensed region where ribosomes are formed.
  • Peroxisome metabolizes waste.
  • Endoplasmic Reticulum
    • Rough: associated with ribosomes; makes secretory and membrane proteins.
    • Smooth: makes lipids.
  • Vacuole
  • Plasmodesmata channels connect two plant cells
  • cell wall maintains cell shape
  • plasma membrane
  • cytoplasm
  • Central Vacuole filled with cell sap that maintains pressure against cell wall
  • Cytoskeleton:
    • microtubules
    • intermediate filaments
    • microfilaments
  • Chloroplast site of photosyntesis
  • Ribosomes
  • Golgi apparatus
  • Mitochondria
  • Plastid store pigments

Animal Cell

  • Cytoskeleton
    • Microtubules: form the mitotic spindle and maintain cell shape.
    • Centrosome: microtubule-organizing center.
    • Intermediate filaments: fibrous proteins that hold organelles in place.
    • Microfilaments: fibrous proteins; form the cellular cortex.
  • Plasma membrane
  • Lysosome: digests food and waste materials.
  • Golgi apparatus: modifies proteins.
  • Cytoplasm
  • Mitochondria: produce energy.
  • Nucleus contains chromatin, a nuclear envelope and a nucleolus
  • Peroxisome

Fungal Cells

  • Have a cell wall that is made of chitin and other polymers instead of cellulose.
  • May have several nuclei within a single cell.
  • Cannot make their own food through photosynthesis because they lack chloroplasts.

Virus

  • A nonliving particle made up of a nucleic acid and either a protein or lipid-protein coat.
  • Viruses cause many diseases in living organisms and are useful tools for genetic research.
  • Viruses are extraordinarily small; smaller than prokaryotic cells.
  • Viruses do not have cytoplasm or organelles and thus cannot carry out cell functions such as metabolism.
  • They cannot grow by dividing.
  • To reproduce, viruses must enter a living cell and use that cell's (the host cell's) ribosomes, enzymes, ATP, and other molecules to reproduce.

Movement Across The Cell Membrane

  • HOMEOSTASIS- the need for an organism to maintain constant or stable internal conditions.
  • Homeostasis depends, in part, on appropriate movement of materials across the cell membrane.
  • The CELL MEMBRANE regulates the passage of material into and out of the cell.
  • Materials needed for cellular processes must pass into cells so they can be utilized.
  • Each individual cell exists in a fluid environment, and the cytoplasm within the cell also has a fluid environment. The presence of a liquid makes it possible for molecules (such as nutrients, oxygen, and waste products) to move into and out of the cell.
  • A cell membrane is SEMIPERMEABLE (SELECTIVELY PERMEABLE) - some molecules can pass directly through the cell membrane while other molecules cannot.

Types of Transport Across the Cell Membrane:

  • PASSIVE TRANSPORT - molecules move across a cell membrane but do not require energy from the cell.

Diffusion

  • The spreading out of molecules across a cell membrane until they are equally concentrated.
  • Results from the random motion of molecules and occurs along a concentration gradient (molecules move from an area of higher concentration to an area of lower concentration).
  • Oxygen, carbon dioxide and water can diffuse either into a cell or out of a cell.

Facilitated Diffusion

  • Some molecules that are not able to pass directly through a cell membrane are able to enter the cell with the aid of TRANSPORT PROTEINS.
  • Transport proteins provide access across the cell membrane.
  • Occurs along a concentration gradient and does not require energy from the cell.
  • Some molecules have chemical structures that prevent them from passing directly through a cell membrane.
  • Glucose passes through the cellular membrane using facilitated diffusion.