Biology The study of life
Genesis 1:11 Then God said, Let the land produce vegetation: seed-bearing plants and trees on the land that bear fruit with seed in it, according to their various kinds. Genesis 1:20 And God said Let the water teem with living creatures, and let birds fly above the earth across the expanse of the sky. Genesis1:24 And God said, Let the land produce living creatures according to their kinds: livestock, creatures that move along the ground, and wild animals, each according to its kind.
Genesis 1: 26 Then God said, Let us make man in our image, in our likeness, and let them rule over the fish of the sea and the birds of the air, over the livestock, over all the earth, and over all the creatures that move along the ground. Genesis 2: 7 The Lord God formed the man from the dust of the ground and breathed into his nostrils the breath of life and the man became a living being.
A living thing Is made of one or more cells Responds to stimuli Maintains homeostasis Metabolizes Grows and develops Reproduces
A closer look at cells Smallest unit that can perform all of life s processes (listed on previous page) Unicellular organisms made of one cell Multicellular organisms made of more than one cell
Responds to Stimuli Stimuli are physical or chemical changes in the internal or external environment Living things respond to stimuli Response to external stimulus: you put a jacket on when it is cold outside Response to internal stimulus: you feel thirsty when your body is low on fluids
Homeostasis The body s ability to maintain a stable level of internal conditions even though environmental conditions are constantly changing Our responses to stimuli help us maintain homeostasis
Examples of Homeostasis Your body temperature normally ranges about 98.6 F whether you are on a sunny beach or playing in the snow Your blood sugar level remains around 82-110mg/dL whether you are at the movies eating candy or have not eaten in six hours
Metabolism Living things need energy to power everything they do Metabolism is the term used to describe all the chemical reactions that occur in a living thing to create the energy it needs Plants metabolize through the process of photosynthesis taking in sunlight to transform carbon dioxide and water into glucose, oxygen, and energy
Growth Nonliving things like crystals grow by accumulating more of the same material they are made of Living things grow through the division and enlargement of cells Cell division is the formation of two new cells from an existing cell
Development Process by which an organism becomes a mature adult Involves cell division and cell differentiation (specialization) Example: eye cells are different than kidney cells are different than skin cells, etc.
Reproduction The process of transmitting hereditary information from a living organism to their offspring Two kinds of reproduction: sexual and asexual reproduction Sexual reproduction: hereditary information recombines from two organisms of the same species, resulting offspring are similar but not identical to their parents Asexual reproduction: hereditary information from different organisms is not combined so the original and the new are genetically identical
Reproduction Asexual Reproduction Sexual Reproduction
How are living things organized? Matter is anything that occupies space and has mass Everything in the universe is made up of matter Mass is the quantity of matter an object has
More Review.. All matter is made up of the known elements of the periodic table Elements are substances that cannot be broken down chemically into simpler kinds of matter 90% of the mass of living things is composed of combinations of four elements: oxygen, carbon, hydrogen, and nitrogen
Atoms Simplest part of an element that retains all of the properties of that element Protons (+) and neutrons (no charge) are found in the nucleus The number of protons in an atom is called it s atomic number
Atoms The mass number of an atom is equal to the total number of protons and neutrons of the atom Electrons are negatively charged particles that move around the nucleus on energy levels called orbitals Electrons on outer orbitals have more energy than those on inner orbitals
Atoms The number of electrons and protons in an atom are equal giving it an overall neutral condition Atoms of elements can have varying amounts of neutrons, these atoms are called isotopes of the same element
Compounds Atoms of most elements don t exist alone because their electrons readily combine with electrons of other atoms Atoms are chemically stable when the highest energy orbital is filled with the maximum number of electrons Compounds are made up of atoms of two or more elements bonded together A chemical formula shows the kinds and proportions of atoms of each element that forms a particular compound A molecule is the simplest part of a compound that retains all of the properties of that compound
Water Molecule Compound: Water Molecule: H20 Ratio of atoms: two hydrogen atoms and one oxygen atom
Bonding Vocabulary Valence electrons: electrons in the outermost energy level of an atom Oxidation number: the charge (positive or negative) an atom has when it loses or gains electrons. Atoms are neutral when the number of protons (+) equal the number of electrons (-) When atoms lose electrons they will have an overall positive charge because they have more protons than electrons. When atoms gain electrons they will have an overall negative charge because they have more electrons than protons. The oxidation number tells how positive or negative an atom is. an atom that has lost 2 electrons will have an oxidation number ( an overall charge) of +2 an atom that has gained 2 electrons will have an oxidation number (overall charge) of -2
Ionic Bond Bonds between atoms that are created when one atom gives away one or more valence electrons and the other atom gains those electrons.
Covalent Bonds Covalent bonds are created when two atoms share their valence electrons. Carbon has 4 valence electrons and hydrogen has 1so each hydrogen shares the 1 valence electron they have with carbon. The carbon is stable because it has 8 valence electrons now and each hydrogen is stable because they each have 2. Chemical Formula: CH₄
bonding video Please watch before attempting to do ionic and covalent bonding worksheets
Water Water is a polar molecule Polar molecules form when atoms in a molecule have unequal pulls on the electrons they share Because oxygen has more positive protons in its nucleus than either hydrogen, the shared electrons are pulled more towards the oxygen atom (opposite charges attract one another)
Hydrogen bonds Opposite charges of polar molecules can interact to form hydrogen bonds Hydrogen bonds are created between a slightly positive hydrogen atom and a slightly negative atom from another molecule (usually oxygen or nitrogen) Hydrogen bonds exist between water molecules in their solid and liquid states Hydrogen bonds are also found between the sugar molecules and nitrogen bases that help make up an organism s DNA
Hydrogen Bonds Hydrogen bonds are the reason water has a high specific heat Although hydrogen bonds between compounds are 20 times weaker than the ionic or covalent bonds between elements that make up a compound, the hydrogen bonds between water molecules are fairly strong Because of this it takes a great deal of heat to overcome the attractions among water molecules, this allows water to be a liquid at the temperatures that support most life on earth, without the hydrogen bonds all water on earth would evaporate at our temperatures and life on earth could not exist For this is what the Lord says he who created the heavens, he is God; he who fashioned and made the earth, he founded it; he did not create it to be empty, but formed it to be inhabited he says: I am the Lord, and there is no other. (Isaiah 45:18)
Hydrogen Bonds Hydrogen bonds allow water molecules to exhibit cohesion Cohesion is the attraction among molecules of a substance. The cohesion among water molecules makes them stick together You can see this when water forms beads (like on a newly washed car) Cohesion produces surface tension, which makes a kind of skin on water, this keeps water bugs from sinking
Hydrogen Bonds Hydrogen bonds allow water molecules to exhibit adhesion Adhesion is the attraction among molecules of different substances Water molecules stick to other things Adhesion is responsible for the upwards curve on the surface of water ( a meniscus) Adhesion helps plants transport water from their roots to their leaves because water molecules stick to the sides of the vessels that carry the water
Water Many substances like molecules and ions MUSt dissolve in water in order to take part in the chemical reactions within cells that run the processes of life When one substance dissolves in another, a solution is formed A solution is a mixture of substances that is the same throughout (also known as a homogenous mixture) A solution has two parts: solvent and solute The solvent is the substance present in greater amount that dissolves another substance The solute is a substance that gets dissolved in a solvent The amount of solute dissolved in a certain amount of solvent is a solution s concentration (a spoonful of Cool-aid in 8oz of water vs. 16oz of water)
Solutions The liquid portion of the blood is called the plasma, it is about 95% water The solvent in plasma is water and all the substances dissolved in it are the solutes Polar molecules dissolve in water because the attraction between the water molecules and the solute molecules is greater than the attraction among the molecules of the solute themselves Nonpolar substances (ex. Fats and oils) don t dissolve in water because they do not have charged regions that would be attracted to the water molecules
Organic Compounds Most matter in living things is made up of organic compounds Organic compounds contain carbon atoms Carbon has four electrons in its outer-most shell and needs eight to be complete and stable, therefore it bonds covalently to other atoms easily
Types of Organic Compounds Carbohydrates Proteins Lipids Nucleic Acids
Carbohydrates Structure: made of carbon, hydrogen, and oxygen atoms bonded together in different ratios Major jobs in living things: energy, plants use them for cell strength and rigidity too Examples: glucose, FRUCTOSE fructose, galactose GLUCOSE
Proteins Structure: made mainly of carbon, hydrogen, oxygen, and nitrogen Major functions in living things: enzymes, building material for parts Proteins are made up of smaller units called amino acids that are linked together 20 different amino acids, each one has a different shape due to how the atoms bond and therefore can perform many different activities in living things
Proteins Continued Enzymes are made of either protein or RNA molecules and act as catalysts for chemical reactions A catalyst is any substance that helps start a chemical reaction without being changed itself Chemical reactions are necessary in all living things to sustain life Enzyme reactions depend on a physical fit between the enzyme molecule and the substance being catalyzed called a substrate
substrate enzyme Enzymes products of chemical reaction The enzyme has folds called the active site with a shape that allows the substrate to fit into it An enzyme acts only on a specific substrate because only that substrate fits into its active site After the reaction, the enzyme releases the products but is itself unchanged and can be used again many times
Lipids Large organic molecules that do not dissolve in water and contain oxygen, carbon, and hydrogen Include fats, steroids, waxes, and pigments Uses: storage of energy (fats), cell membrane structure (fats), protective coatings (wax), and steroids have many uses in living things (ex. testosterone and cholesterol)
Nucleic Acids Large complex organic molecules that are made up of a chain of nucleotides bonded together A nucleotide is a molecule that consists of a phosphate group, a five-carbon sugar, and a ring-shaped nitrogen base Two kinds of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)
Nucleic Acids Continued DNA: contains information that determines the characteristics of an organism and directs its cell activities RNA: stores and transfers information from DNA that is essential for the manufacturing of proteins, they can also act as enzymes DNA RNA
Organization Continued Organic molecules (as well as others like water) bond together to create small structures in the cell called organelles Organelles carry out functions necessary for the cell to stay alive (ex. nucleus, mitochondria, cell membrane, etc.) Similar cells (basic units of all living things) work together to form tissues (4 types) that perform a specific function in living things
4 Kinds of Tissues Nerve tissue: sends information throughout the body Muscular tissue: causes movement Epithelial tissue: protects, secretes, and absorbs Connective tissue: holds parts together
Organs A group of tissues working together to perform a specific function Examples: heart, liver, lungs, kidney Heart: nervous tissue sends message for the heart to pump, the muscle tissue does the actually pumping (contracting and relaxing), the epithelial tissue forms a protective covering around the heart, and connective tissue holds the heart in its place in the body
Organ System A group of organs acting together to perform a specific function or functions Examples: respiratory system, excretory system, nervous system The digestive system is made up of salivary glands, the tongue, teeth, esophagus, stomach, small intestines, large intestines, liver, gallbladder, and colon
Organism A group of organ systems working together to perform all functions necessary for life make up an organism
ph Water molecules (H₂O) can be broken apart and rearranged into two new molecules: H₃O+ and OHH₃O+ (hydronium ion) OH- (hydroxide ion) When a substance contains more hydronium ions (H₃O+) than hydroxide ions it is called an acid
ph Continued When a substance contains more hydroxide ions (OH-) than hydronium ions it is called a base (alkaline) ph scale is used to compare the relative concentrations of hydronium and hydroxide ions in a solution Ranges from 0 to 14: 0 is the most acidic (highest in hydronium content), 7 is neutral (ratio of each ion is the same), 14 is the most basic (highest hydroxide content)
ph Scale Each change of one ph unit reflects a 10-fold change in the acidity or alkalinity of the substance Example: Urine has 10 times more H3O+ ions at a ph of 6 than water does at a ph of 7
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