Lesson 7.1 - Intro To Cellular Life

Study - New Technology allowed people to study the movement and structure of cells

Microscopes:

• Electron microscopes reveal details 1000 times bigger than visible in light microscopes

• Transmission electron microscopes are used to show cell structure and large protein molecules. Electrons go through and need to be cut into slices

• Scanning electron microscopes create 3D images. Electrons bounce off of and do not have to be cut into small slices

Prokaryotes + Eukaryotes:

• Types of Cells Include:

  • Bacteria, plants, animals, fungi, protists

• All Cells Include:

  • Cell Membrane

  • Cytoplasm

  • Ribosomes

  • DNA

• Prokaryotes:

  • Genetic material not contained

  • No membrane-bound organelles

  • Smaller than eukaryotic cells

  • Bacteria

• Eukaryotes:

  • DNA is stored in the nucleus

  • Long and complex

  • Contain dozens of structures and internal membranes

  • Highly specialized

  • Plants, animals, fungi, protists

• Discovery of Cells

  • James Hooke coined the term “cell”

  • He was attempting to study cork

  • Antonie Van Leeuwenhoek observed microorganisms in pond water under a microscope

  • Matthias Scheider concluded that all plant tissue is made of cells and that cells are a basic unit of life

  • Theodore Schwann concluded that all animal tissue is made of cells

• Properties of Cells/Cell Theory

  • All organisms consist of 1 or more cells

  • Cells are the basic unit of life and structure of all organisms

  • All cells come from preexisting cells

Lesson 7.2 - Eukaryotic Cell Structure

• Eukaryotic Cell Structures:

  • Organelles: Preform cell functions

  • 2 Parts: Nucleus + Cytoplasm

  • Cytoplasm is outside the nucleus

• Plant Cell:

• Animal Cell:

• Endomembrane System:

  • Nucleus - Holds instructions

  • Ribosomes - Build

  • ER - Shape

  • Golgi - Modify/Sort/Package

  • Vesicles - Ships

• Nucleus:

  • Control center

  • Holds instructions for making proteins

  • Surrounded by 2 nuclear envelopes

  • Envelopes contain pores that only RNA can pass through

  • Granular material in the nucleus - Chromatin

  • Chromatin - made of RNA and protein

  • When a cell divides, chromatin condenses to become chromosomes. These contain genetic info

  • The nucleolus only holds info to make more ribosomes

• Ribosomes:

  • Small particles of RNA and protein found freely throughout the cytoplasm

  • Create proteins in “Protein Synthesis”

    • Follow instructions from the nucleus and RNA

• ER:

  • Rough ER (Part of protein synthesis) + Smooth ER (Not part of protein synthesis)

  • Ribsomones on Rough ER are found on the surface

  • Rough ER - Proteins are assembled on ribosomes

  • Smooth ER- Creates lipids and detoxifies drugs

• Golgi Apparatus:

  • Proteins are moved from ER to Golgi

  • Modifies, Sorts, and Packages proteins

  • Sends to vesicles which send to their necessary location

• Making Proteins:

1. Nucleus

2. Nuclear Pore

3. Ribosome

4. Protein

5. Rough ER

6. Golgi Body

7. Vesicle

8. Cell Membrane + to a new location

• Lysosomes:

  • Small organelles filled with enzymes

  • Break down lipids, carbs, and proteins into things that can be used by the rest of the cell

  • Breaks down organelles that no longer have a use

  • “Trash/Recycle”

• Vacuoles:

  • Saclike structures

  • Store water, salts, proteins, and carbs

  • Holds pigments + toxins as defense mechanisms

  • In plant cells - the central vacuole is filled with liquid that is used for photosynthesis + helps the plant stand upright

  • Unicellular Organisms - filled with water and have a pump to help from exploding

• Mitochondria:

  • Convert energy from food into compounds that can be used more conveniently by the rest of the cell

  • Enclosed by 2 membranes

  • More folds = more surface area = more energy = more ATP

• Choloplasts:

  • Capture energy from the sun and convert it into chemical energy

  • Photosynthesis

  • Surronded by 2 membranes

  • Contain chlorophyll

• Cytoskeleton:

  • Gives eukaryotic cells their shape

  • A network of protein filaments

  • Also involved in cell movement

• Microfilaments:

  • Thread-like structures made of the protein actin

  • Make extensive networks in cells

  • Make a tough, flexible framework that supports the cell

  • Helps move cells

• Microtubules:

  • Hollow structures that are made up of the protein tubulins

  • Help maintain cell shape

  • Helps cells divide (mitosis+meosis)

  • Build projections from the cell surface that enable cells to swim rapidly through liquids

  • Centrioles are also formed from tubulins

  • These are located near the nucleus and help organize cell division

Lesson 7.3 - Cell Boundaries

• All cells have a thin, flexible barrier known as the cell membrane

• Plants, fungi, bacteria + some protist cells also produce a stronger layer known as a cell wall

  • The main function of the cell wall is to provide support and protection for the cell

  • No movement - extra padding

  • Also attacks bacteria

  • Lies outside the cell membrane

  • Porous enough to allow water, oxygen, carbon dioxide, and other substances to easily pass through

• Cell Membrane

  • Regulates what enters and exits the cell

  • Provides support and protection for the cell

• The composition of nearly all cell membranes is made of a double-layered sheet called a lipid bilayer

  • Gives a flexible structure that forms a barrier between a cell and its surroundings

  • Contains protein molecules embedded in the lipid bilayer, some of which have carb molecules attached to them

• Diffusion Through Cell Boundaries

  • Every cell lives in a liquid environment

  • The cell membrane regulates the movement of diffusion from the liquid on one side of the membrane to another

  • Particles tend to move from areas of high concentration to low concentration

  • This is the process of diffusion

  • This will continue until a state of equilibrium is reached

• Passive Transport

  • Depends upon random particle movements

  • Substances diffuse across membranes without using energy

  • This is called passive transport

• Osmosis

  • Diffusion of water through a selectively permeable membrane

  • Water - solvent - what is doing the dissolving

• Levels of Concentration

  • Water diffuses from areas of high to low concentration

  • More concentrated solution - Hypertonic

  • Area of high concentration

    • Water with more sugar present

  • Less concentrated solution - Hypotonic

  • Area of low concentration

    • Water with less sugar present

  • Water with equal parts sugar and water

    • Isotonic

  • Osmosis is only concerned with water and its’ levels

  • Particles never stop moving, as they must always work to maintain homeostasis

• Osmotic Pressure

  • Occurs when water on the hypertonic side puts pressure on the membrane

  • The cell is almost always hypertonic to fresh water

  • If a cell has too much water, it is at risk of exploding or bursting (which leads to the death of the cell)

  • Cells in large organisms and with cell walls are much less likely to burst

• Facilitated Diffusion

  • Membranes contain integral proteins that can assist in the movement of larger particles

  • The use of these proteins is called facilitated diffusion

  • Protein channels are specific to certain particles only

  • Ex. Glucose Transport - Only for glucose

  • Fast and Specific

  • Still considered diffusion

  • Only occurs from high to low concentration

• Active Diffusion

  • Occurs when materials have to move from areas of low to high concentration

  • Against the concentration difference

  • Requires energy

    • Ex. Stuffing things into a closet

• Molecular Transport

  • Small molecules are carried by proteins

  • Allows movement from low to high

  • Requires energy

• Large Particle Transport

  • Occurs when particles are too large to be carried by proteins

  • Active transport

• Endocytosis

  • Process of taking material into the cell by means of pockets of the cell membrane

  • A vacuole is formed around the material that works to bring it into the cell

  • This vacuole is from the cell membrane

• Phagocytosis

  • The process of cytoplasm surrounding food

  • This is then engulfed by the cell

  • Requires energy

    • Collect

    • Pinch Off

    • Turns to Vesicle

    • Engulfed by Cell

• Pinocytosis

  • The process of cytoplasm surrounding waste

  • This is then removed from the cell

  • Requires energy

    • Collect

    • Pinch Off

    • Turns to Vesicle

    • Released

• Exocytosis

  • The release of waste from a cell

  • Cell membrane fuses with waste from inside the cell

  • Then removes it from the cell

  • Requires energy

Lesson 7.4 - Diversity of Cellular Life

• Unicellular Organisms

  • Made of only 1 cell

  • Dominate life on Earth because so many of them can fit per any given space compared to multi

  • Includes: All bacteria cells, certain eukaryotic organisms (yeast + amebas)

• Multicellular Organisms

  • Made of many cells

  • Great variety in these cells

  • Includes: All plant cells, all animal cells, most fungus cells, some protist cells

• Specialized Animal Cells

  • Red blood cells transport oxygen

  • Cells in the pancreas produce a protein (endomembrane systems)

  • Muscle cells allow for movement

• Specialized Plant Cells

  • Exchange carbon dioxide, oxygen, water vapor, and other gases through stomata

  • Guard cells surround the stomata and regulate the exchanges

• Levels of Organization

  • Individual Cells - 1st level of organization

  • Tissues - Cells are grouped and create these

    • A group of similar cells that perform a particular function

  • Organ

  • Organ Systems

  • Organism

  • Ex. Muscle cell > Smooth muscle tissue > Stomach > Digestive System

• Types of Tissue (Animals)

  • Muscle - Moves

  • Skin - Epithelial

  • Nervous - Neurons

  • Connective - Ligaments/Cartlidge

• Organs (Animals)

  • Groups of tissues that work together to perform a specific function

  • Completes a series of specialized tasks

  • Work together to create organ systems

    • Nervous System

    • Circulatory System

    • Skeletal System

    • Digestive System