C HAPTER 2: I T ’ S A LIVE !! O R I S I T ? 7 th Grade Life Science

S TANDARDS 7.1 a Students know cells function (to work) similarly ( in almost the same way) in all living organisms. 7.2 a Students know the differences between life cycles (a repeating series of changes) and reproduction methods of sexual and asexual organisms.

S PIDER MAP Through cell division In life stages Grow and Develop For chemical processes Use energy Controls heredity DNA cells Structural unit Functional unit Sense and Respond to change Internally (homestasis) externally Reproduce sexually asexually

S ECTION 1 C HARACTERISTICS OF L IVING THINGS Key Concept: Living things have six characteristics in common. Vocabulary Cell: the smallest functional and structural unit in all living organisms Homeostasis: the maintenance of a constant internal state in a changing environment Sexual reproduction: reproduction in which the sex cells from two parents unite to produce offspring that share traits from both parents Asexual reproduction: reproduction that does not involve the union of sex cells and in which one parent produces offspring that are genetically identical to the parent Metabolism: the sum of all chemical processes that occur in an organism

L IVING THINGS HAVE CELLS All living things are composed of _______________ cells All cells are surrounded by a _______________ In one celled organisms, different parts of the cell perform different functions. In organisms made up of _______ cells, specialized cells perform specialized functions

L IVING THINGS SENSE AND RESPOND TO CHANGE A change that affects the activity of an organism is called a stimulus (stimuli – plural) Can be chemicals, gravity, light, sounds, hunger, or anything that causes a response in the plant Homeostasis Conditions on the inside of an organism must stay the __________ no matter what goes on outside An organism must maintain stable internal conditions to _________________.

L IVING THINGS SENSE AND RESPOND TO CHANGE Responding to External Changes The body will sweat when ________ or shiver when ________ to maintain homeostasis. Some organisms will move from one environment to ____________ to maintain their body temperature.

L IVING THINGS REPRODUCE Living things make offspring like themselves by either _______________ reproduction or ____________________ reproduction.

L IVING THINGS HAVE DNA DNA – Deoxyribonucleic Acid Carries the instructions for the organism’s __________ When organisms reproduce, they pass copies of their ______ to their offspring. The passing of the traits is known as _________

L IVING THINGS USE ENERGY Use energy to carry out chemical activities Examples Changing energy into ________ Breaking ________ food Moving material ______ and ______ of cells Growing ______________ cells Metabolism: sum of all activities performed by the _________________

L IVING THINGS GROW AND DEVELOP All living things __________ during parts of their lives Single celled organisms get __________ and divide. Multicellular organisms The number of cells _____________ The organism gets _______________

S UMMARY OF SECTION 1 Organisms are made up of ______ or _______ cells. Organisms _________ and __________ to stimuli. Organisms reproduce through ___________ or ___________ reproduction. Organisms have __________. Organisms use __________ to carry out their activities. Organisms ________ and ____________.

S ECTION 2 T HE NECESSITIES OF LIFE Key Concept: Every living thing needs water, a place to live, and food in order to survive. Vocabulary Producer: an organism the can make its own food by using energy from its surroundings Consumer: an organism that eats other organisms or organic matter Decomposer: an organism that gets energy by breaking down the remains of dead organisms or animal wastes and consuming or absorbing the nutrients Protein: a molecule that is made up of amino acids and that is needed to build and repair body structures and to regulate processes in the body.

V OCABULARY Carbohydrate: a class of molecules that includes sugars, starches, and fiber Lipid: a fat molecule or a molecule that has similar properties Phospholipid: a lipid that contains phosphorus and that is a structural component in cell membranes ATP: adenosine triphosphate, a molecule that acts as the main energy source for cell processes Nucleic Acid: a molecule made up o subunits called nucleotides

F OUR N ECESSITIES OF L IFE WATER Makes up 70% of your cells and the cells of almost all living things Most chemical reactions require ______________ Organisms differ in how much water they need and how they get it People can survive ____ days without water Why do cells require water? _______________________________________________ _______________________________________________ _______________________________________________

F OUR N ECESSITIES OF L IFE AIR Mixture of several gases including _____________, _______________, and ____________ ______________ Some organisms use oxygen from the ______ or may be dissolved in _____________. Some organisms use oxygen and carbon dioxide to produce ___________ and oxygen in the process of photosynthesis Some organisms do not need air Anaerobic organisms are those that can live without __________

F OUR N ECESSITIES OF L IFE A PLACE TO LIVE All living things need a place to live that has all of the things that they need to ______________ Space on Earth is _____________. Organisms must ______________ for food, water, and other necessities.

F OUR N ECESSITIES OF L IFE FOOD Food gives _____________ Not all organisms get food in the same way. They can be grouped into three categories. ProducerConsumerDecomposer Plants Make their own food Use photosynthesi s to produce food and oxygen Eat other organisms Rely on others for food and oxygen Break down nutrients from dead organisms or animal waste Must eat their food

P UTTING I T A LL T OGETHER Some living things ________ their own food. Some get food from _____________ other organisms. All organisms must break down their food to use the ______________ in it. Nutrients are made up of molecules ( a substance made when two or more atoms join together) Molecules of different kinds of atoms are compounds. Molecules found in living things are ___________, ___________, ____________, _____________, _____________ and ____________.

P ROTEINS Almost all live processes involve ___________ Proteins are made up of smaller molecules called __________ _____________. Some proteins are made up of only a few amino acids while others are made up of thousands Proteins in Action ______________ have many functions Some proteins help other cells do their jobs like hemoglobin in the red blood cells. They can ______________ cells Enzymes start up or speed up chemical reactions in ________. What function do enzymes in cells serve?

C ARBOHYDRATES Molecules made of ______________ Provide and store ___________ for the cells. Simple Carbohydrates One or a few sugar molecules Table sugar and the sugar in fruits are examples Glucose is the most common source of energy for cells Complex Carbohydrates When an organism has more sugar than it needs it makes ______________ carbohydrates Made up of hundreds of sugar molecules Potatoes store extra sugar as STARCH

L IPIDS Molecules that cannot mix with water Some store energy and others form the membranes of the cells Phospholipids All cells are surrounded by a cell membrane __________________ are the molecules that form much of the cell membrane Head is attracted to water, the tail is not List two functions of cell membranes. __________________ and ________________________ Fats and Oils Lipids that store _________________ Most lipids stored in plants are ____________ and animals are ____________

ATP Adenosine triphosphate Major ________ carrying molecule of cells Energy in carbohydrates and lipids is transferred to __________ to provide fuel for cellular activities

N UCLEIC A CIDS Carry the directions for how to make ___________ Made up of smaller molecules called ____________ There could be thousands Sequence stores information DNA is a nucleic acid Like a cookbook called How to Make Proteins Cells get directions from the ______________ of the nucleotides in DNA Tells the cell the order in which amino acids are ___________ together to make the protein.

S UMMARY The cells of living things need __________ to function. The cells of some living things need gases, such as oxygen, to release the energy contained in ______. Living things must have a ________ to live. Cells store energy in carbohydrates, which are made up of ____________. Proteins are made up of ___________________. Some proteins are enzymes. Lipids store energy and make up ______ membranes. Cells use molecules of ______ to fuel their activities. Nucleic Acids, such as _______, are made up of nucleotides.