Chapter 2 Flashcards
2 systems for maintaining homeostasis
Endocrine and Nervous System
Communication->____________->homeostasis->good health
regulation
Put these in the right order-
Organ system, cell, organelle, organism, organ, chemical
Chemicals->organelle->cell->organ->organ system->organism
What is an Atom?
the smallest partical of an element that can display the characteristics of that element and enter into an ordinary chemical reaction
What is an ion?
When an atom looses or accepts one or more electrons
what is the difference between a cat ion and anion?
if the ion is positively charged it is a cat ion
if the ion is negatively charged it is a an ion
What is the Atomic Weight?
Average mass number of all isotopes of an element
What is Atomic mass number?
of protons and neutrons
What is an isotope?
Different # of neutrons in a different atoms of the same element
Which two elements can have a maximum of 2 electrons in their valence shells?
hydrogen and helium
How does a cat ion become a cation?
How does an anion become an anion?
By giving away an electron-cation and by having a positive charge
By accepting an electron-anion and by having a negative charge
What do ionic bonds from?
New substances
Are ionic bonds strong?
No
what does valent refer to in covalent bond?
the valence shell
In a covalent bond, electrons are?
Shared
What is a non polar covalent bond?
The electrons are shared equally in the bond
example-Hydrogen or any time there are atoms of the same element form a covalent bond it will always be a non polar bond
What is a polar covalent bond?
Electrons are shared unequally between the two atoms
example-H20
Do hydrogen bonds form new substances?
no
How strong are hydrogen bonds?
Very weak, but strength in numbers
What does a straight line represent?
a covalent bond
What does a dotted line represent?
a hydrogen bond
What is a hydrogen bond?
A bond between hydrogen and either oxygen or nitrogen
Where do hydrogen bonds form?
They form on the hydrogen end
What are the functions of hydrogen bonds?
Hold molecules together, dictate shape or hold DNA together
What are molecules?
When two atoms join to form structures held together by covalent bonds
Changing the shape of a molecule does what?
It changes it’s function
If you had an atom with 11 protons and 12 neutrons, is that more likely to become a cation or an anion?
It would more than likely become a cation
*****
Chemical actions that build bonds do what?
store energy
Chemical reactions that break bonds do what?
release energy
If energy that is stored was all released at once within a cell?
It would produce to much heat and the cell would be destroyed
What is the energy currency molecule in the cell?
ATP
Energy within a cell needs to be released in _______ quanties?
small