Chapter 2 - The Nature of Life Flashcards
Attributes of living organisms
Composition and structure Growth Reproduction Response to stimuli Metabolism Movement Complexity and organization Adaption to the environment
Bonds and ions
Covalent bonds
Ionic bonds
Hydrogen bonds
Growth
Increase in mass, usually accompanied by an increase in volume.
Nucleus
Part of atom containing protons and neutrons.
Protons
- Positively-charged part of an atom
- Has mass
- Affects the path of electrons around the nucleus
Atom
The smallest stable subdivision of an element that can exist
Reproduction
Offspring always resemble the parents more than other individuals of the same kind. (see chapter 13)
Orbital
- Region occupied by electrons around the nucleus
* A volume of space in which a given electron occurs 90% of the time.
Isotopes
Variations of elements with slightly different numbers of neutrons in the atoms, resulting in different weights but all forms behaving alike chemically
Electrons
- Negative charges that whirl around the nucleus.
Valence
The combining capacity of an atom or ion based on electron number.
Covalent bonds
Form when two atoms complete their outermost energy level by sharing a pair of electrons in the outermost orbital. They hold two or more atomic nuclei together and travel between them.
Neutrons
- Part of an atom with no electrical charge
* Has mass
Hydrogen bonds
Form when positively charged hydrogen atoms in polar molecules are attracted to negatively charged atoms in other polar molecules.
Acids
Chemicals that release hydrogen ions (H+) in water
Ionic bonds
Molecules that lose or gain electrons and become either positively or negatively charged particles.
Compound
A substance where 2 or more elements are united in a definite ratio by chemical bonds.
Molecule
- The smallest unit of an element or compound retaining its own identity.
- 2 or more atoms bound together
pH
- Scale (0-14) to measure acidity or alkalinity
- Each unit (0-14) represents a tenfold change in H+ concentration.
- Pure water is 7/neutral, number of H+ and OH- is the same.
Thermodynamics
Study of energy and its conversions from one form to another.
Bases (alkaline compounds)
- Feel slippery or soapy
* Compounds that accept H+ ions.
Second law of thermodynamics
Energy contained within a system and is converted from one form to another, flows from a high to a low state (heat flows from hot objects to cool surfaces).
Polymers
“Many units”
- formed when two or more monomers bond together
First law of thermodynamics
Energy is constant – it cannot be gained or lost – but can be converted from one form to another. Forms include: chemical, electrical, heat, and light.
Monomers
“Single unit”
- smaller cell components that bond through dehydration synthesis to create polymers
Characteristics of matter
- Occupies space
- Has mass (weight)
- Composed of elements
Monosaccharides
- a kind of carbohydrate (polymer)
- Simple sugars with backbones of 3-7 carbon atoms
- includes glucose, fructose
Disaccharides
- a kind of carbohydrate (polymer)
- formed when two or more monosaccharides bond via dehydration synthesis
- includes sucrose (glucose+fructose)
Carbohydrates
- One of the most important classes of polymers.
- The most abundant organic compound in nature.
- Includes sugars, starches
- CH2O
Cellulose
Chief structural polymer in cell walls (3000-10000 chains of glucose molecules)
Lipids
- Fatty or oily substances insoluble in water because contain no polarized components
- store twice as much energy as carbohydrates
- important to long-term energy reserves of cells
- broken down by hydrolosis
Polysaccharides
- A kind of carbohydrate (polymer)
- Formed when more than 2 monosaccharides bond together
- example is starch, a string of glucose molecules that have bonded, each giving up a molecule of water
Proteins
- second only to cellulose in making up dry weight of plant cells
- regulate chemical reactions in cells
- usually very large molecules of one or more polypeptide chains
Polypeptides
Chains of amino acids
Amino acids
a
Peptide bonds
- Link together amino acids through covalent bonds
Storage proteins
a
Growth
- An increase in mass, usually accompanied by an increase in volume.
- Results from the production of new cells and includes variation in form.
- Controlled by a plant’s genetic makeup and the environment in which its grown.
Enzymes
a
Nucleic acids
a
Nucleotides
a
Response to Stimuli
Plants respond to injury and other stimuli, such as light, temperature, and gravity.
Metabolism
The collective product of all the biochemical reactions taking place within an organism. Most important activities: respiration, photosynthesis, digestion, assimilation.
Movement
Most plants movements are slow, imperceptible, and mostly related to growth. Not confined to the organism as a whole, but occurs at the cellular level.
Complexity of an Organization
Cells contain large numbers of molecules (more than 1 trillion molecules in a single cell). Numbers of molecule types can be in the millions for flowering plants and other large objects.
Reproduction
Offspring always resemble parents more than they do other individuals of the same kind.
Genes
a
Organic compounds
Have a “backbone” of carbon atoms
Inorganic compounds
Have no carbon atoms (except carbon dioxide CO2 and sodium bicarbonate NaHCO3)
Dehydration synthesis
Bonds two monomers together when H+ is removed from one monomer and hydroxyl OH- removed from the other creating an electrical attraction
- also known as a condensation reaction
Hydrolysis
Opposite of dehydration synthesis, when H+ from water attaches to one monomer and OH- to another, resulting in energy being released
Isomer
Molecules with the same numbers and kind of atoms but different in structure and shape
Sucrose
The form in which sugar is transported through plants
Waxes
- A kind of lipid
- usually embedded in cutin or suberin (also lipids) on leaf surfaces
- provide waterproofing, prevent water loss, protection against insects and microorganisms
Phospholipids
- a kind of lipid
- constructed chemically like fats but with some polarized ions
- important component in membranes in living organisms
Adaptation to the Environment
Response to air, water, light, soil, genetic fitness.
Energy
The ability or capacity to do work or to produce a change is motion or matter.
