Feeney Bio Midtterm

Midterm Review

Microscope Diagram

• Eye Piece: The lens you look through, typically 10x or 15x magnification.

• Objective Lenses: Different lenses that provide varying levels of magnification, often labeled as 4x, 10x, 40x, and 100x.

• Stage: The flat platform where the slide is placed for observation.

• Light Source: Illuminates the specimen, which can be a built-in light or an external lamp.

• Coarse Focus Knob: Used for making large adjustments to the focus of the microscope.

• Fine Focus Knob: Used for making small adjustments to the focus for clearer images.

Characteristics of Life (DR GECHEE!!!)

• All living things:

  • Are made of cells

    • Uni-cellular: “single celled” (example: yeast or paramecium)

    • Multi-cellular: “many celled” (example: plants and animals)

  • Reproduce

    • Sexual: two cells from different parents join (half from “Mom” and half from “Dad”)

    • Asexual: genetically identical to one parent

  • Are based on a universal genetic code (DNA determines inherited traits)

  • Grow and develop

    • Exhibit a life cycle; grow and change during the organism’s lifespan

  • Obtain and use energy

    • Energy is used for chemical reactions; known as metabolism (the sun is the ultimate source of energy)

  • Respond to their environment

    • Example: plants turn toward the sun

  • Maintain a stable internal environment

    • This process is known as homeostasis (e.g., sweating when hot, shivering when cold)

  • Evolve or change over time

    • Evolution is the gradual adaptation process of organisms over time.

History of Cells

• 1665: Robert Hooke - used a light microscope to observe thin slices of cork and named the structures "cells"

• 1838: Matthias Schleiden - all plants are made of cells

• 1839: Theodore Schwann - all animals are made of cells

• 1853: Rudolph Virchow - all cells come from existing cells

Levels of Organization

• Biosphere: The whole world, including all biotic and abiotic factors

• Ecosystem: All biotic and abiotic things in a particular area

• Community: All organisms living in a specific area

• Population: A group of organisms

• Organism: One individual made up of organs forming organ systems

• Tissues: Make up organs that form organ systems

• Cells: Basic unit of life

• Molecules: Composed of atoms

Scientific Method

1. Define the Problem

2. Background Research

3. Form a Hypothesis

4. Design a Controlled Experiment

5. Observe, Record and Analyze Data (ORA)

6. Draw Conclusions

7. Communicate Results

   • Theory or A NEW PROBLEM!!!

Basic Cell Structure

• Cell Membrane: Thin, flexible barrier that contains the cytoplasm.

• Cell Wall: Strong layer outside the cell membrane (support and structure).

• Nucleus: Contains genetic material and controls cell activities.

• Cytoplasm: Material inside the cell membrane (excludes nucleus).

• Nucleolus: Region in the nucleus where ribosomes are assembled.

• Nuclear Envelope: Double membrane with nuclear pores.

• Cytoskeleton: Support the cell with microtubules and microfilaments.

• Ribosomes: Make proteins, respond to coded messages; produced in the nucleus.

• Endoplasmic Reticulum (ER): Internal membrane system; Rough ER synthesizes proteins; Smooth ER has no ribosomes.

• Golgi Apparatus: Modifies, sorts, and packages proteins.

• Lysosomes: Enclose enzymes; break down particles.

• Vacuoles: Store salts, proteins, carbohydrates; help support plant structures.

• Chloroplasts (plants only): Convert sunlight into glucose (photosynthesis).

• Mitochondria: Powerhouse of the cell, use energy for growth and movement.

Cell Membrane Structure

• Fluid Mosaic Model: Membranes are fluid and proteins/lipids can move.

• Diffusion: Movement from high concentration to low concentration.

Types of Solutions**

• Hypotonic: Solute concentration outside the cell is lower, causing water to move into the cell.

• Hypertonic: Solute concentration outside the cell is higher, causing water to move out of the cell.

• Isotonic: Solute concentration is equal inside and outside; water moves in and out.

Endocytosis/Exocytosis

• Endocytosis: Moves large molecules and fluids into the cell.

• Exocytosis: Releases contents out of the cell.

pH Scale

• pH means “potential of hydrogen.”

• Scale ranges from 0-14, with 7 as neutral.

• Acids: 0-6 pH (e.g., lemon juice).

• Bases: 8-14 pH (e.g., soap).

Chemistry of Life

• Atom: Basic unit of matter.

• Element: Pure substance of one type of atom.

• Isotopes: Atoms of the same element with different neutron numbers.

• Molecules: Smallest units of covalently bonded compounds.

• Covalent Bonds: Atoms share electrons (e.g., H2O).

• Ionic Bonds: Transfer electrons between atoms (e.g., NaCl).

Macromolecules

• Carbohydrates: Energy and structure; examples include glucose and starch.

• Proteins: Repair/build tissues; examples include enzymes.

• Nucleic Acids: Store and transmit genetic information (DNA and RNA).

• Lipids: Store energy; examples include fats and oils.

Cell Growth and Division

• Cell Division: Process of a cell dividing into two daughter cells.

• Chromosomes: Contain cell's genetic material (DNA).

• Cell Cycle:

  • Interphase: Cell performs normal functions.

  • Mitosis: Cell division phases (prophase, metaphase, anaphase, telophase).

  • Cytokinesis: Division of cytoplasm into two cells.

DNA Structure

• Nucleotide: Basic structure (nitrogenous base, phosphate group, deoxyribose sugar).

• Double Helix: Structure of DNA, discovered by Watson and Crick.

• Nitrogenous Bases: Adenine, Cytosine, Guanine, Thymine.

• RNA: Contains ribose instead of deoxyribose, Uracil instead of Thymine.

Summary of RNA Types

1. mRNA: Carries genetic message to ribosomes.

2. tRNA: Transfers amino acids to ribosomes.

3. rRNA: Makes up ribosomes with proteins.

The Big Four Macromolecules

Mitosis

• Mitosis is the process of cell division resulting in two genetically identical daughter cells.

• Phases include:

  • Prophase: Chromosomes condense and become visible.

  • Metaphase: Chromosomes align at the cell's equator.

  • Anaphase: Sister chromatids are pulled apart to opposite poles.

  • Telophase: Nuclear envelopes re-form around each set of chromosomes.

• Followed by Cytokinesis, which divides the cytoplasm.

Meiosis

• Meiosis is a type of cell division that produces four genetically diverse gametes with half the chromosome number of the original cell.

• Phases include:

  • Meiosis I: Homologous chromosomes are separated; results in two haploid cells.

    • Prophase I: Homologous chromosomes pair and exchange genetic material (crossing over).

    • Metaphase I: Homologous pairs align at the equator.

    • Anaphase I: Homologous chromosomes are pulled apart.

    • Telophase I: Nuclear membranes may reform.

  • Meiosis II: Similar to mitosis; sister chromatids are separated; results in four haploid gametes.

    • Prophase II: Chromosomes condense again.

    • Metaphase II: Chromosomes align at the equator.

    • Anaphase II: Sister chromatids are pulled apart to opposite poles.

    • Telophase II: Nuclear membranes reform, resulting in four genetically unique cells.