Biology Unit 4 updated

homeostasis

when the body maintains equilibrium

* production of organisms is vital for maintaining homeostasis
* the maintenance of homeostasis is essential for life

control center

part of the body that processes information from the receptor and sends a response to the effector

effector

an organ that carries out the response to a nerve impulse

endocrine system

the biological systems that consists of groups of glands responsible to the secretion of hormones

testosterone

a chemical substances secreted by endocrine glands into the bloodstream that controls or regulates specific physiological processes

hypothalamus

the portion of the brain below the thalamus and above the brainstem

internal feedback mechanism

an evolved response to a change in homeostasis; occurs when one level of a substance stimulates a response in another substance or organ system

negative feedback

a control mechanism in which a change in the body triggers a response that counteracts the change

* stops the stimulus
* ex. the baby sitting in the stomach for 9 months
* ex. lowering body temperature from original state

types of passive transport

* diffusion: movement of a solute through a solvent
* facilitated diffusion: the passive movement of molecules along the concentration gradient
* osmosis: the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules

concentration gradient

change in one concentration to another

diffusion

* movement of a solute through a solvent
* requires membrane proteins

osmosis

is the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules

* facilitated diffusion

* the passive movement of molecules along the concentration gradient
* plasma membranes

active transport

the movement of __ions__ or molecules across a cell membrane into a region of higher concentration, assisted by __released__ energy.

* diffusion

passive transport

the movement of substances across a cell membrane down their concentration gradients, which does not require energy.

* facilitated diffusion

positive feedback loops

encourages the stimulus

* ex. having the baby

plasma membrane

a semipermeable because it acts as a gatekeeper for the cell

* large molecules can only pass through if energy is used
* Small nonpolar molecules like oxygen and carbon dioxide can diffuse into and out of the cell through the plasma membrane easily.
* Polar molecules, or ions such as sodium, cannot diffuse through the membrane without help.

osmosis

Diffusion of water through a semipermeable membrane

ATP

The primary molecule used by cells to store \n chemical energy for use in cellular processes.

* is used for many jobs to supply cellular energy

maintaining homeostasis

1. receptors (collects information about the body)
2. control center (receives signals from receptors)
3. effectors ( communicates with control center to put the mechanism in effect)

cellular respiration

The process by which cells convert chemical energy \n stored in various compounds, such as sugars, into useful \n energy for cellular processes

glucose

A monosaccharide sugar, C6H12O6

glycosis

The breakdown of glucose into pyruvate to produce ATP and NADH

* the first step in both cellular respiration and fermentation
* anaerobic step
* creates 2 ATP

krebs cycle

A part of aerobic respiration that uses the products of glycolysis and fatty acid oxidation to generate ATP and NADH for oxidative phosphorylation

light-dependant reactions

The set of reactions in photosynthesis in which \n chlorophyll absorbs light energy to make ATP and \n NADPH

aerobic

requiring oxygen

2 step process: krebs cycle then \n Electron transport chain

krebs cycle steps (aerobic)

1. The two pyruvic acid molecules formed during glycolysis move into the mitochondria, where they initiate a series of enzymatic reactions that release electrons and hydrogen ions, and produce carbon dioxide and two molecules of ATP.
2. The carbon dioxide diffuses out of the \n mitochondria.
3. The electrons and hydrogen ions are carried to the electron transport chain on NADH (a carrier protein molecule similar to NADPH).

\n Electron transport chain steps (aerobic)

1. Products from the Krebs cycle move across the inner membrane of the mitochondria.
2. electrons are shuttled back and forth across the inner \n mitochondrial membrane as part of this process.
3. the enzyme ATP synthase adds phosphate to ADP, making 2 ATP molecules per glucose

aerobic respiration

produces 34 ATP

products of photosynthesis

glucose and oxygen

reactants of photosynthesis

carbon dioxide and water

anaerobic

doesn’t require oxygen

glycolysis without oxygen

In a low-oxygen environment, pyruvic acid can be turned into lactic acid as an alternate pathway for making small amounts of ATP.

light dependant and light independent combined reactions

produces equation for photosynthesis 6CO2 + 6H2O + (light energy) → C6 H12 O6 + 6O2

polar

an uneven partial charge distribution between the atoms.

non polar

molecules like lipids have an even distribution of charge

need more help?

read kendricks stemscopedia Homeostasis , Photosynthesis and Cellular Respiration.pdf, transport, Plasma Membrane and Movement of Materials.pdf

hypertonic solutions

the water concentration outside of the cell is lower than the concentration inside the cell and eventually will become dehydrated

hypotonic solutions

the water concentration outside of the cell is higher than the concentration inside the cell. Water molecules will flood into the cell, and it will swell.

single celled organisms maintaining homeostasis

using a special vacuole to actively pump excess water out through the plasma membrane.

animal celled organisms maintaining homeostasis

uses tissues and organs like kidneys to \n maintain the body’s water concentration outside the body cells.