science test

atom

the smallest unit of a substance that maintanes the properties of that substance

element

a substance that is made entirely of one type of atom

molecule

a group of atoms held together by attractive forces called chemical bonds

a compound

a molecule that contains at least two different elements

cell

the smallest functional and structural unit of all living things

organelle

_______ have special functions that keep the cells working properly

eukaryotic cell

cells with a nucleus

prokaryotic cell

cells that dont have a nucleus surrounding their genetic material

cell membrane

surrounds the cell

cytoplasm

the gel-like liquid inside the cell

mitochondria

in eukaryotic cells, cellular respiration occurs in these organelles

DNA

genetic material in the form of a long molecule

cell theory

1) all organisms are made of cells

2) cells come from existing cells

3) the cell is the basic unit of life

4) cells take in and use energy for life

organic compounds

a chemical compound that contains carbon atoms

4 types of organic molecules

1) proteins-contain amino acids

2) carbohydrates- made of C-H-O carbon, hydrogen, and oxygen

3) lipids- long branching chains of hydrogen and carbon

4) nucleic acids- DNA and RNA made of nucleotides

cytoskeleton

________ is throughout the cytoplam of eukaryotic cells

genetic material

Any material of plant, animal, microbial or other origin that carries genetic information and that passes it from one generation to the next

cellular respiration

in ________, cells use oxygen to produce energy from food

ribsosomes

the organelle that makes proteins by putting together chains of amino acids using instructions encoded in the cell’s DNA

plant cells- eukaryotic cell

1) cell wall

2) vacuole

3) chloroplasts

animals- eukaryotic cell

1) lysosome

organism

a living thing that can carry out life processes by itself

unicellular organism- not specialized for any one function, need fewer resources and can live in harsh conditions. If one cell dies it is dead.

made up of just one cell that performs all of life functions

multicellular organism- has specialized cells which are organized at levels: cells to tissues to organs to organ systems

made up of more than one cell

organs

a structure made up of a collection of two or more tissues that carries out a specialized function

structure

the arrangement of parts in an organism or an object

function

the structure of a cell, tissue, or organ

homeostasis

maintaining a stable balance in the body

a unicellular organism

exchanges materials directly with its environment. The cell membrane helps to regulate materials and maintain homeostasis

cells in multicellular organisms……

must work together to maintain homeostasis for the entire organism. Systems transport materials to cells from other places in the organisms

mitosis

when equal numbers of chromosomes are sperated, and the nucleus splits to from two identical nuclei

passive transport

the movement of particles across a cell membrane without the use of energy by the cell

diffusion

the movement of molecules from high concentrations to low concentrations

osmosis

the diffusion of water through a semi-permeable membrane

active transport

the movement of particles against a concentration gradient and requires the cell to use energy

producers

some living things, such as plants and many single-celled organisms

consumers

many living things, such as people and other animals

decomposers

a special group of consumers is made up of…..

photosynthesis, only plants: what is needed and what comes out of it

plants use energy from sunlight, carbon dioxide, and water to make sugars

chloroplasts

photosynthesis takes place in organelles called _______

chlorophyll

chloroplasts contain a green pigment called ______

cellular respiration, both plants and animlas. what is needed and what comes out

the process of breaking down food to produce ATP

stimulus

anything that causes a reaction or change in an organism

response

an organisms reaction to a stimulus

behavior

a set of actions taken by an organism in response to a stimulus

hormone

a chemical signal produced in one part of an organism that affects cell activity in another part of the organism

taxis

the movement of organisms toward or away from an external stimulus

tropism

the movement of a plant in response to an external stimulus, such as light or gravity

migration

animals that live in enviornments where it is difficult to survive year-round will move to enviornments where conditions are more favorable for survival

hiberantion

a deep sleep during which an animal slows down its body processes to save energy

species

a group of organisms that can reproduce only with one another and not with other organisms

population

a group of organisms of the same species that live in the same place at the same time

variation

the differences that occur in individuals within a species

artificial selection

the practice by which humans breed specific plants or animals for deisred traits

natural selection

the process by which organisms that inherit helpful traits tend to reproduce more successfully than other organisms do

overproduction

more offspring are usually born than the envirornment can support. only some of them will survive into adulthood, and a smaller number of them will successfully reproduce

genetic variation

within a population there are naturally occuring variations in traits. genetic differences, or variations, pass from parents to their offspring

selection

individuals try to get the resources they need to survive. these resources include food, water, space, and, in most cases, mates for reproduction

adaptation

an inherited trait that improves survival and reproductive success of an organism