Biology 8 Vocab: Test 2

Cell Theory

• All living things are made of cells

• Cells are the basic unit of structure and function in living things

• New cells are produced from existing cells

Microscopes

an instrument used for viewing very small objects

Prokaryotes

• cells that do not enclose DNA in nuclei

• Smaller and simpler that Eukaryotic cells

• They grow, reproduce and respond to the environment

• Some can even more by gliding along surfaces or swimming through liquids

Eukaryotes

• cells that enclose their DNA in nuclei

• Larger, complex and highly specialized

• Contains dozens of structures and internal membranes

Organelles

• cell structures that act as specialized organs and carry out specific functions

• Organelles means “little organs”

• Helps us to understand the cell as a whole

Cell Wall

• In plant cells

• Provides support and protection to the cell

• Outside the cell membrane

• Porous enough to let water, oxygen, and carbon dioxide inside

Cell Membrane

• In both plant and animal cells

• Thin, flexible, barrier surrounding the cell that controls what comes in and out

• Supports the cell

• Keeps the cell’s internal conditions constant

Cytoplasm

• In both plant and animal cells

• Gel-like fluid in the cell

• Outside the nucleus

• Where many organelles are found

Nucleus

• In both plant and animal cells

• Control center of the cell

• Houses the cell’s DNA and instructions for making proteins and other molecules

Nuclear Envelope

• In both plant and animal cells

• Made of two membranes

• Surrounds nucleus

• Dotted with thousands of pores that allow material to enter and exit the nucleus

Chromatin

• In both plant and animal cells

• Form in which chromosomes are spread throughout the nucleus

• Thread like complex of DNA bound to proteins

Nucleolus

• In both plant and animal cells

• Where the assembly of ribosomes begins

Mitochondria

• In both plant and animal cells

• Power plants of the cell

• Converts chemical energy from food into compounds the cell can use

• Contains its own genetic material

Endoplasmic Reticulum

• In both plant and animal cells

• Passageway that carries materials

• Where lipids are assembled and proteins are exported

Rough Endoplasmic Reticulum

• In both plant and animal cells

• Part of the ER involved with making proteins

• Ribosomes found on the surface

• Newly made proteins leave these ribosomes and are inserted into the rough ER, where they may be chemically modified

Smooth Endoplasmic Reticulum

• In both plant and animal cells

• Ribosomes not found on the surface

• Contains collections of enzymes that perform specialized tasks including the synthesis of membrane lipids and the detoxification of drugs

Ribosomes

• In both plant and animal cells

• Small particle of RNA and protein found throughout the cytoplasm in all cells

• Assembles proteins by following coded instructions that come from DNA

Golgi Apparatus

• In both plant and animal cells

• Modifies, sorts and packages proteins and other materials from the ER for storage in the cell or release outside the cell

• Customization Shop/UPS

• From the Golgi Apparatus, proteins are shipped to their final destination inside or outside the cell

Chloroplasts

• In plant cells

• “Solar power plants”

• Captures energy from sunlight and converts it into food/chemical energy during photosynthesis

• Contains green pigment chlorophyll

Vacuoles

• In both plant and animal cells

• Large, sacklike membrane enclosed structures that store materials such as water, salts, proteins and carbohydrates

• Plant cells have a large central vacuole filled with liquid which provides rigidity, allowing for plants to support heavy structures such as leaves and flowers

Vesicles

• In both plant and animal cells

• Used to store and move materials between cell organelles as well as to and from the cell surface

Lysosomes

• In both plant and animal cells

• “Clean up crew”

• Removes junk that might otherwise accumulate and clutter up the cell

• Breaks down lipids, carbs, and proteins into molecules that can be used by the rest of the cell

Cytoskeleton

• In both plant and animal cells

• Helps cell maintain shape

• Also involved in movement

• Made of microfilaments and microtubules

Centrioles

• In animal cells

• Located near the nucleus

• Helps to organize cell division

Compounds

two or more elements joined together in a chemical reaction

Organic Compounds

A compound that includes carbon

Macromolecules

large molecules

Carbohydrates

• Made of carbon, oxygen and hydrogen

• Their monomers are monosaccharides

• They are used for the  main source of energy in all cells in living things and sugars specifically provide short term energy

• Both the cell wall and cell membrane are made of carbs

• Used for structural purposes in some organisms

• Sugars and starches are both kinds of carbohydrates

• Some examples of carbs are bread and pasta

Lipids

• Made of carbon, hydrogen and oxygen

• Their monomers are fatty acids and glycerol

• They are used for energy and are able to provide even more energy than carbohydrates

• Energy is stored in the form of lipids

• Are able to provide long term energy

• Make up most of cell membranes

• Used for waterproofing

• Usually aren’t soluble in water

• Fats, oils, and waxes are made of lipids

• Some examples are butter and avocado

Proteins

• Made of carbon, hydrogen, oxygen, and nitrogen

• Their monomers are amino acids

• Make up most cells

• They help in immune systems as well

• They form cellular structures such as the cytoskeleton 

• They help transport substances in or out of a cell

• Some examples of proteins are meat, eggs, fish and nuts

Nucleic Acids

• Made of carbon, hydrogen, nitrogen and phosphorus

• Their monomers are nucleotides

• Directs the cells activity

• Stores and transmits genetic information

• The two kinds are DNA and RNA

• DNA is the genetic material that holds information about a living thing and is passed from parents to children.

• DNA is stored in the nucleus of a cell

• RNA helps to make proteins and is stored in both the cytoplasm and in the nucleus

• Can be found in all living things, such as meat, fish, fruit and vegetables

Selectively Permeable

some substances can pass through while others cannot

Phospholipid Bilayer

two layers of phospholipids molecules that make up the cell membrane

Diffusion

• moving from an area of high concentration to an area of lower concentration

• Requires no energy

• Called concentration gradient

• Main method on how small molecules move across the cell membrane

• Particles constantly move, randomly collide and spread out evenly

Equilibrium

when  the concentration of a system is the same throughout

Osmosis

• the diffusion of water through a selectively permeable surface

• water can pass through most biological membranes

• Movement of water molecules from higher to lower concentration

• Extremely important biological process

Isotonic

when the concentration of water inside the cell is the same as outside the cell

Hypertonic

when there is a low concentration of water and a high concentration of solute outside the cell causing water to move out of the cell

Passive Transport

the movement of dissolved materials through a cell membrane without the use of energy

Active Transport

the movement of materials through a cell membrane using cellular energy from low to high concentration

Endocytosis

the process of taking material into the cell

Exocytosis

the process by taking material in large amounts out of the cell

Facilitate Diffusion

• molecules that cannot directly diffuse across the membrane get help from special proteins

• How glucose passes through the cell membrane

• Protein channels are used

• This takes no energy

• It allows specific molecules to pass through

Aquaporin

• water channel proteins that allow water to pass right through them

• Without them water would diffuse in and out of cells very slowly

Hypotonic

when there is a high concentration of water and a low concentration of solute outside the cell causing water to move into the cell