Chapter 1: Organization, Cells, Transport, Osmosis

chemical level of organization

is the simplest level of biological organization, consisting of atoms and molecules that form the basic building blocks of cells.

cellular level of organization

is the level where cells are formed from molecules and organelles, functioning as the basic unit of life.

tissue level of organization

is the level where groups of similar cells work together to perform a specific function, forming tissues such as muscles, nerves, and epithelial layers.

organ level of organization

is the level where different types of tissues come together to form organs, which perform specific functions essential for the body's survival.

organ system level of organization

is the level where different organs work together to perform complex functions necessary for the organism's overall functionality, such as the circulatory or digestive system.

organism level of organization

is the level where all organ systems work together to maintain life and health of an individual organism, representing the highest level of biological organization.

lymphatic system

is a network of tissues and organs that help rid the body of toxins, waste, and other unwanted materials, playing a vital role in immune function and fluid balance.

respiratory system

is a system of organs responsible for taking in oxygen and expelling carbon dioxide, essential for gas exchange and maintaining respiratory function.

digestive system

is a system of organs that breaks down food, absorbs nutrients, and removes waste, crucial for providing energy and maintaining overall health.

urinary system

is a system of organs that produces, stores, and eliminates urine, playing a key role in regulating fluid balance and filtering waste products from the blood.

male reproductive system

is a system of organs involved in the production, maturation, and transport of sperm, essential for reproduction and hormonal regulation.

female reproductive system

is a system of organs responsible for producing and transporting ova, supporting fertilization, and providing a site for fetal development, crucial for reproduction and hormonal regulation.

homeostasis

is the process by which biological systems maintain a stable internal environment despite external changes, crucial for the survival of organisms.

cell membrane is made of…

phospholipids, carbohydrates, proteins

heads of the lipid bilayer are…

hydrophilic; bounce off lipid, need help getting through

tails of the lipid bilayer are…

hydrophobic; pass through without help

glycocalyx

“ID markers” - differentiate different types of cells from one another (my cells vs.your cells)

functions of membrane proteins

receptors, ion channels, transport proteins

receptor

receives signals from other cells

ion channel

allows hydrophilic ions to pass through the cell membrane (charged molecules) (specific ones for specific ions)

transport proteins

act as an Uber for hydrophillic non-ions and gets them to where they need to be

functions of a membrane

1. physical boundary between other cells or structures

2. Communication between body organ systems (ex. heart cells and blood vessel cells)

3. Controls passage of material in & out of cell (semi-permeable)

   1. Hydrophobic: pass right through

   2. Hydrophillic: need “help”

4. Maintain gradients

How do cells communicate?

Endocrine signaling = Cell A sends hormones through bloodstream to Cell B where they go to receptors and elicit a physiological response.

Paracrine signaling: between two neighboring cells = Cell A sends directly to cell B to elicit a physiological response.

gradient

the difference between the inside & outside of a cell in concentration, pressure, pH, temperature, etc.

Higher concentration

the down gradient; moving from high conc. to low conc.; going down the hill

Requires no ATP

lower concentration

Up gradient; moving from low conc. to high conc.; going back up the hill.

Requires ATP

passive transport

requires no ATP

moving with the gradient from high to low

active transport

Requires ATP

moves against the gradient from low to high.

Requires transport proteins

simple diffusion

type of passive transport involves hydrophobic molecules moving across a membrane without energy.

facilitated diffusion

type of passive transport that uses protein channels to assist hydrophilic molecules in crossing a membrane without energy.

vesicular transport

type of active transport that involves the movement of materials in and out of cells via vesicles, requiring energy. (Exocytosis/Endocytosis, Na+/K+ pump)

endocytosis

the process by which cells “eat” substances by engulfing them in a vesicle, requiring energy. (ex. killing bacteria)

exocytosis

the process by which a cell expels materials in a vesicle, requiring energy.

What is diffusion rate dependent on?

size of molecule: smaller = faster diffusion

size of gradient: bigger gradient = faster diffusion

surface area: more membrane = faster diffusion

membraane thickness: thicker membrane = slower diffusion

similarities between active transport and facilitated diffusion

both require “help”

deal with hydrophilic molecules

differences between active transport and facilitated diffusion

active transport: requires ATP; goes from low to high concentration.

Facilitated diffusion: does not require ATP; goes from high to low concentration.