Bio 105 Test 1 Chap 1-3

All living organisms grow

for unicellular (one celled) organisms, ____ is an increase in cell size before reproduction. For multicellular organisms, ___ refers to an increase in an organisms size as the number of cells making up the organism increases

All living organisms reproduce

_____ is the process of producing new organisms. Offspring are similar, but not necessarily identical, to their parents in general structure, function and properties

All living organisms maintain homeostasis

_____ is the maintenance of a relatively constant internal environment. Organisms maintain a stable internal environment, even when the external environment changes

All living organisms sense and respond to stimuli

___ are events that invoke a response. Organisms respond to ___ in many ways such as moving towards a food source or away from a threatening predator.

All living organisms obtain and use energy

All living organisms require an input of energy to power their activities. Organisms obtain energy from food (which they either produce themselves by photosynthesis or consume from the environment). Chemical reactions convert that energy into usable forms. The sum total of all these reactions is metabolism.

All living organisms share five properties that define them as ‘alive’ except

A mule who is alive but cannot reproduce (sterile) and fire which reproduces and uses energy but is not alive.

Matter

is anything that takes up space and has mass

Elements

substances that cannot be chemically broken down

Atom

the smallest unit of an element that still retains the property of that element

Nucleus

is the dense core of an atom

Atomic number

number of protons in an atom

carbon

4th most common element in the universe, 2nd most common element in the human body. key component of the molecules of living organisms, can form multiple covalent ponds and bond up to 4 atoms

covalent bond

the sharing of a pair of electrons between two atoms

organic molecules

carbon based backbone and at least one C-H bond

inorganic molecules

lack carbon-based backbones and C-H bonds

Macromolecules

large organic molecules composed of monomers linked together to form polymer chains, Ex: carbohydrates, Proteins, Lipids, Nucleic acids

Carbohydrates

made of repeating subunits of simple sugars (monomers)

Proteins

folded polymers made of repeating units of amino acids, always the same atoms in the main chain with different groups of atoms in the side chain

Lipids

non made of repeating monomers, hydrophobic (don’t mix with water)

Nucleic acids

polymers made of repeating nucleotide subunits Ex: DNA and RNA

Cell membrane

double layer (bilayer), separate the contents of a cell from it’s environment

Water

all of life’s chemical reactions take place in water, it is composed of a oxygen and two hydrogen atoms, and many of its functions are due to its shape, cohesion, adhesion, freezing at 0C and boiling at 100C, solid water is less dense than liquid water so ice floats

polar molecule

electrons in bonds do not share equally between atoms, partial negative charge at one end and a partial positive charge at the other

Hydrogen bonds

water forms special attractions known as _____ bonds with water and other molecules, they give water its unique properties

cohesion

molecules cling to each other Ex. water has this property

adhesion

molecules cling to other surfaces Ex. Water has this property

Solvent

a substance in which another substance dissolves

Solute

a dissolved substance

Solution

the mixture of solute and solvent

Ionic bonds

strong bonds formed between oppositely charged ions

Ion

a charged atom due to loss or gain

pH

measure of the concentration of hydrogen ions in a solution, ranges from 1-14

Cell theory

all living things are made of cells, and every new cell comes from the division of a pre-existing cell

Prokaryotic cells

lack internal membranes-bound organelles

Eukaryotic cells

membrane-bound organelles, including a nucleus; resist effects of antibiotics

similarities of prokaryotic and eukaryotic cells

cell membrane of phospholipids and proteins, cytoplasm (gelatinous aqueous interior), ribosomes ( a complex of RNA and protein that carry out protein synthesis), DNA as a molecule of heredity

Differences of Prokaryotic and Eukaryotic cells

Only eukaryotic cells: a nucleus (organelle that contains DNA), many organelles'

Only prokaryotic cells: DNA floating freely in cytoplasm, no organelles, cell wall made of peptidoglycan, a rigid structure enclosing the cell membrane

Cell membrane

to have an effect on the cell substances such as antibiotics must first cross the cell membrane, all cells have a cell membrane, the membrane is semipermiable

Phospholipids (lipids, fats, triglycerides)

primary component of cell membranes, hydrophobic and partly hydrophilic, form a bilayer in an aqueous environment (hydrophilic heads point toward the water, hydrophobic tails point away from the water)

semipermeable

prevents many large molecules, such as glucose and hydrophilic (charged) substances, such as sodium ions, from crossing; allows small unchanged substances to cross via diffusion

Simple diffusion

natural tendency of dissolved substances to move from an area of higher concentration to one of lower concentration, no energy required

transport proteins

assist large or hydrophilic molecules in crossing the membrane; act as a channel, carrier, or pump; can move specific substances across membranes

facilitated diffusion

large or hydrophilic solutes diffuse across a membrane help of transport proteins; allows substances to move from area of higher concentration to lower concentration; does not require energy input

Active Transport

uses the help of transport proteins, requires energy input, pumps solutes to the side of the membrane with higher solute concentration

Nucleus

eukaryotes,encloses the cell’s DNA, reactions for interpreting the genetic instructions take place here, surrounded by the nuclear envelope

Endoplasmic reticulum

eukaryotes, network of membrane-covered ‘pipes’, proteins and lipids synthesized here, rough ER and smooth ER

Golgi apparatus

eukaryotes, stacked membranous discs, receives proteins from ER via vesicles, packages and transport proteins

mitochondria

eukaryotes, extract energy from food (ex. macromolecules such as carbs, lipids, and proteins), convert energy into useful form that cells use (ATP or adenosine triphosphate)

Chloroplasts

eukaryotes, plants and algae have them, site of photosynthesis (capture and conversion of sunlight energy into a usable form)

lysosomes

full of digestive enzymes, break down worn-out cell parts and food molecules

Cytoskeleton

network of protein fibers; function include cell support and movement, and movement of structures within cells

Endosymbiosis theory

free-living prokaryotic cells engulfed other free-living prokaryotic cells billions of years ago, forming mitochondria and chloroplasts