9th Grade Biology Review

nucleus

a part of the cell containing DNA and RNA and responsible for growth and reproduction

cell membrane

thin, flexible barrier around a cell; regulates what enters and leaves the cell

ribosome

small particle in the cell on which proteins are assembled; made of RNA and protein

rough endoplasmic reticulum

a region that is recognized by the grainy appearance of the ribosomes on their outer surface, where the cell's proteins are made

lysosome

cell organelle filled with enzymes needed to break down certain materials in the cell

smooth endoplasmic reticulum

no ribosomes are found on surface; contains collection of enzymes that perform special tasks that include the synthesis of membrane lipids and detoxification; the liver contains a lot of smooth er

golgi apparatus

stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum

mitochondria

the organelles in which nutrients are converted to energy

eukaryotic cell

cell with a nucleus (surrounded by its own membrane) and other internal organelles

prokaryotic cell

cell lacking a nucleus and most other organelles

hypotonic solution

a solution in which the concentration of solutes is less than that of the cell that resides in the solution

hypertonic solution

a solution in which the concentration of solutes is greater than that of the cell that resides in the solution

isotonic solution

a solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solutionosmosis

osmosis

diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal

diffusion

process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated

cellular respiration

the process by which cells use oxygen to produce energy from food

g1phase

Cells grow and mature

s phase

DNA replication

g2 phase

The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

prophase

first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus

metaphase

second phase of mitosis, during which the chromosomes line up across the center of the cell

anaphase

the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles

telophase

the final stage of mitosis or meiosis, during which a nuclear membrane forms around each set of new chromosomes

dominant genes

the genes that dictate the way a trait is expressed

recessive genes

genes that are expressed only in the absence of a dominant gene

p generation

parental generation, the first two individuals that mate in a genetic cross

f1 generation

the first offspring from a cross of two varieties in the parental (P) generation

macromolecules

four main classes of large biological molecules (carbohydrates, lipids, proteins, nucleic acids)