All living things are made up of cells! Specialized cells develop from a single zygote Organisms are made up of specialized cells. Each has a specific job/function red blood cell nerve cell
Zygotes (fertilized egg) first divide into embryonic stem cells. Stem cells can become any of 200 types of cells in the human body.
Stem cells develop in two stages. 1. Determination: committing to become one cell type 2. Differentiation: acquiring specialized structures and functions
Specialized cells function together in tissues, organs, organ systems, and the whole organism. Specialized cells perform specific tasks. Tissues are groups of similar cells working together. Types: o epithelial tissue o connective tissue o muscle tissue smooth (stomach) skeletal (bicep) cardiac (heart) o nervous tissue cell tissue
Organs are different tissues working together. Organ systems are two or more organs working together. Organism is all organ systems working together. ORGANS ORGAN SYSTEM ORGANISM
TISSUE ORGANS ORGAN SYSTEM CELL ORGANISM
There are 11 major organ systems in the human body.
How does our body make sure we don t die in the next 5 minutes?
Conditions within the body must remain within a narrow range. Homeostasis involves keeping the internal environment within set ranges (temperature, ph, water, vitamins, minerals, etc). Examples of your body under homeostasis When you are cold, your body will shiver. When you are hot, your body will sweat.
Feedback loops are necessary for homeostasis. Feedback compares current conditions to set ranges. Negative feedback counteracts change. Negative Feedback Loop Holding breath, CO 2 levels rise, O 2 / CO 2 level returns to normal Control system forces exhale, inhale
Positive feedback increases change that is needed to maintain normal conditions Torn vessel stimulates release of clotting factors platelets blood vessel fibrin clot red blood cell white blood cell growth hormones stimulate cell division
How do we make sure we keep our body functioning at its best? Let s look at the cellular level
The Physiological Environment Physiological Environment: the internal conditions that optimize (make the best use of) individual cell function and body organization
The Physiological Environment External Environment: conditions outside of the cell Internal Environment: conditions within the cell
How are cells able to change because of their environment? A selectively permeable membrane!
Molecular Transport Diffusion: movement of molecules from an area of high concentration to low concentration. Semi-permeable or Selectively permeable
Molecular Transport Diffusion: movement of molecules from an area of high concentration to low concentration. ** dilemma: cells must prevent their contents from diffusing into their environment while at the same time diffusing certain molecules in and out of the cell.
Passive Transport Passive Transport: diffusion across a membrane WITHOUT energy; instead, the cell relies on a diffusion gradient as the driving force for moving molecules.
Passive Transport Membrane diffusion relies on the fact that certain particles can pass through a membrane. Why? Because of LIPIDS! Facilitated diffusion is a form of passive transport that uses a carrier protein to move ion and molecules through a membrane.
Passive Transport Membrane diffusion relies on the fact that certain particles can pass through a membrane. Why? Because of LIPIDS! Facilitated diffusion is a form of passive transport that uses a carrier protein to move ion and molecules through a membrane.
Passive Transport Osmosis: the diffusion of WATER across a selectively permeable membrane; moves towards more solute (usually a salt). SALT SUCKS!
OSMOSIS The solute (large circles) is more concentrated on the right side, which pulls the water molecules toward that side. The large circles would move to the left to spread out evenly, BUT the membrane won't let those pass.
Solutions That Affect Cells ISOTONIC SOLUTION
Solutions That Affect Cells HYPOTONIC SOLUTION
Solutions That Affect Cells HYPERTONIC SOLUTION
Plasma Membrane
Active Transport Active transport pumping: an energyconsuming process where a cell moves ions and molecules across its membrane. Notice the direction of the concentration gradient & the direction of the molecules The molecules move AGAINST the gradient. Hence, ENERGY NEEDED!!
Bulk active transport: moves large amounts of particles into and out of the cell. Types: Active Transport Endocytosis: moves large amounts of particles INTO a cell
Type of Endocytosis Receptor-mediated endocytosis: uses receptor proteins to bind molecules.
Active Transport Exocytosis: removes large amounts of molecules OUT of the cell. Excretion: removal of waste Secretion: transport of important molecules
Endocytosis And Exocytosis