BIO exam 1

Homeostasis

The maintenance of a relatively constant internal environment.

Energy

The capacity to do work. Cellular work includes processes such as building complex molecules and moving substances into and out of the cell.

Atomic number

The number of protons in an atom, which determines the atom’s identity.

Covalent bond

A strong interaction resulting from the sharing of a pair of electrons between two atoms.

Organic molecules

Describes a molecule with a carbon-based backbone and at least one C-H bond. Ex: glucose

Inorganic molecules

Describes a molecule that lacks a carbon-based backbone and C-H bonds. Ex: carbon dioxide.

Carbohydrates

Monosaccharide. Ex: Glucose. Elements are carbon, hydrogen and oxygen. Provides fast energy to the cell. Form cell walls of fungi and plants.

Lipids

Fatty acid tails, glycerol. Elements are carbon, hydrogen, and oxygen. Provides long-term energy. Insulate (hold in heat). Form cell membrane.

Protein

Amino acid. Elements are carbon, hydrogen, oxygen and nitrogen. Form enzymes (speed up reactions). Aid in movement & support (muscles, hair, nails). Form antibodies to fight disease. Transport materials (through cell membrane & throughout the body).

Nucleic Acid

Nucleotide: sugar, phosphate, base. Elements are carbon, hydrogen, oxygen, nitrogen, phosphorus. Provide instructions for building proteins. Direct functions of the cell. Store genetic information.

Cell

Basic structural unit of living organisms

Cell membrane

A phospholipid bilayer with embedded proteins that form the boundary of all cells. Controls what enters and leaves the cell. Allows for gas exchange.

Hydrophobic

Water fearing; hydrophobic molecules repel water.

Hydrophilic

Water loving; hydrophilic molecules attract water.

Polar molecule

A molecule in which electrons are not shared equally between atoms, causing a partial negative charge at one end and a partial positive charge at the other. Water is a polar molecule.

Hydrogen bonds

A weak electrical attraction between a partially positive hydrogen atom and an atom with a partial negative charge.

Cohesion

The attraction between molecules (or other particles).

Adhesion

The attraction between molecules (or other particles) and a surface.

Ionic bonds

A strong electrical attraction between oppositely charged ions formed by the transfer of one or more electrons from one atom to another.

Viruses

Reproduce and pass their genetic information on to new viruses, but they are not made of cells. They consist of a protein shell that encloses one or more DNA or RNA molecules containing genetic information.

Prions

Noncellular, self-reproducing entity. Infectious proteins that are responsible for “mad cow disease” and related illnesses.

Cell theory

All living things are made of cells. Cells are the basic structural/functional units of life. New cells come from the division of existing cells. DNA is passed from one cell to another. All cells have the same basic composition.

Prokaryotic

Relatively small cells and lack internal membrane-bound organelles.

Eukaryotic

Much larger and contain many different organelles.

Cytoplasm

Made up of about 80% water. Provides support to the cell. Location of many chemical reactions.

Ribosomes

Composed of 2 subunits made of protein and RNA. Location of protein synthesis. Put together amino acids to create a protein.

Cell membrane

Formed of two layers of phospholipids with proteins and cholesterol. Controls what enters and leaves the cell. Allows for gas exchange.

Nucleus

Surrounded by a membrane with pores. Includes the nucleolus (where ribosomes are synthesized). Location where DNA is stored. Provides directions to create proteins.

Mitochondria

Contains 2 membranes. Often bean shaped. Site of cellular respiration. Organic molecules are broken down to create ATP energy (catabolism).

Chloroplast

Organelle has 2 membrane layers. Contain chlorophyll Thylakoids & Stroma. Site of photosynthesis. Carbon dioxide and water are converted into glucose and oxygen in the presence of lights, (anabolism). Found in plants & photosynthetic protists.

Lysosome

Vesicle filled with enzymes (proteins). Breaks down waste, recycles cell parts. Only animal cells.

Cytoskeleton

Made of mictrotubles and microfilaments. Provides structure to animal cells. Holds organelles in place.

Cell wall

Made of complex carbohydrates such as cellulose and chitin. Provides structure and support to plant and fungal cells.

Vacuole

Many small vacuoles in an animal cell. Large central vacuole found in plant cells. Stores water, nutrients or waste. Provides structure and support to plant cells.

Endoplasmic reticulum

Passageways. Can be connected to the nuclear membrane. Smooth -lipids. Rough ribosomes. Collect and transport material, such as lipids. Form transport vesicles.

Golgi apparatus

Modify, package and ship material throughout the cell or out of the cell through th cell membrane. Form vesicles.

Passive transport

Movement without the use of energy. Particles move naturally from areas of high concentration to areas of low concentration.

Active transport

Movement requires energy. Particles move from low concentration to high concentration.

Biofuels

Renewable fuels made from living organisms. (plants and algae).

Fossil fuels

Coal, petroleum, natural gas

Chemical energy

Potential energy stored in the bonds of biological molecules.

Conservation of energy

The principle that energy cannot be created or destroyed, but can be transformed from one form to another.

Kinetic energy

The energy of motion (heat energy)

Adenosine Triphosphate

The molecule in cells that powers energy-requiring functions.

Carbon fixation

The conversion of inorganic carbon (e.g. CO2) into organic forms (e.g. sugars like glucose C6H12O6).

Why are photosynthetic organisms like algae so important?

All living organisms require energy to live and grow. The ultimate source of energy on Earth is the sun. Photosynthetic organisms convert the energy of sunlight into energy-rich food molecules.

What are the different types of energy, and what transformations of energy do organisms carry out?

Energy is neither created nor destroyed, but is converted from one form into another; this principle is known as conservation of energy. Kinetic energy is the energy of motion and includes heat energy. Potential energy is stored energy and includes chemical energy.

How do plants and algae convert the energy in sunlight into energy-rich molecules?

Photosynthesis is a series of chemical reactions that captures the energy of sunlight and converts it into chemical energy in the form of sugar. This energy is used by all living organisms to fuel cellular processes. Photosynthesis can be divided into two main parts: a “photo” part, during which the pigment chlorophyll captures light energy and water is split to produce high-energy electrons, and a “synthesis” part, during which captured energy and electrons are used to fix carbon dioxide into glucose. Photosynthetic organisms are known as autotrophs (“self-feeders”); they include plants. algae, and some bacteria. Animals do not photosynthesize; they are known as heterotrophs (“other-feeders”).

How do algal biofuels compare to other fuels in terms of costs, benefits, and sustainability?

Photosynthetic algae convert glucose into energy-rich oils that can used as fuel to power automobiles and aircraft. These biofuels show promise as alternatives to fossil fuels.