Cells and Systems Unit Review

Living Organisms the basic unit of life is called a CELL –cells are organized into tissues and organs to perform different functions unicellular organisms → single-celled multicellular organisms → many-celled all organisms –need energy from the sun or food –respond and adapt to their environment –reproduce so life goes on –grow –produce wastes (by-product of using energy)

Value of Microscopes made of small lenses magnify objects so we can see them Leeuwanhoek made the first one –magnified things 300x –he saw single cell organisms today –compound light microscopes can magnify something 2000x –electron microscopes can magnify something 2,000,000x

Parts of a Compound Microscope

Structures of a Cell Cell Membrane – containment Cell Wall – structure Cytoplasm – distribution (food, oxygen) Nucleus – control centre Vacuole – storage containers Chloroplast – photosynthesis

Cell Functions cells need a constant supply of oxygen, water and food to work they also need to get rid of waste products everything that comes into or goes out of a cell must pass through the cell membrane –the membrane is selectively permeable → allows some substances and stops others

Fluid Movement in Cells diffusion - spreading out of particles from an area of more concentration to areas of less concentration –food, oxygen, etc. move into cell –waste product move out of the cell osmosis – diffusion of water through a selectively permeable membrane

Fluid Movement in Plants plants need a lot of water to make food by photosynthesis water comes into the plant by through the root hairs (by osmosis) air (oxygen) comes in through openings on leaves called stomata water is lost from the plant by transpiration (a types of evaporation) 2 types of vascular tissues that transport things around inside the plant: –phloem tissues transport sugars made in leaves, to the rest of the plant –xylem tissues transports water and minerals from roots to other parts of the plant

Cell Specialization & Organization cells are specialized for particular tasks cells with the same structure and function are grouped into tissues –e.g. muscle tissue, nerve tissue, skin tissue –e.g. phloem and xylem tissue groups of different tissues form organs –e.g. stomach, lungs, heart, eyes –e.g. roots, stems, leaves organs work together in systems –e.g. digestive system, circulatory system –e.g. root system (below ground) and shoot system (above ground)

multi-cellular organisms have advantages over single-celled organisms: –can grow large –can live in a variety of environments –can get energy from a variety of foods –can work more efficiently

Human Body Systems SystemFunctions Digestivebreaks down food, absorbs food particles, eliminates waste Respiratoryexchanges oxygen and carbon dioxide Circulatorycirculates blood which transports food particles, dissolved gases and other materials Nervouscontrols and co-ordinates body activities; senses internal and external changes Excretoryregulates blood composition and gets rid of waste fluids

Human Body Systems respiratory system –mouth/nose → larynx →trachea → lungs (bronchus, bronchioles, alveolus) –diaphragm is the muscles that moves the air –inhalation: breathing in fills lungs with oxygen- rich air –exhalation: breathing out gets rid of carbon dioxide waste

digestive system –mouth → stomach → intestine –food is broken down along the way into small, soluble particles that can be used by cells –waste is expelled circulatory system –includes heart, blood and blood vessels (artery, vein, capillary) –takes food from digestive system and oxygen from respiratory system and distributes it to cells all around the body –carries waste away from cells for disposal

excretory system –filters waste from the blood and gets rid of it –key organs are the kidneys nervous system –helps your body interpret and respond to stimuli (e.g. hot or cold on skin) –includes brain, spinal cord & nerves endocrine system –glands the produce chemicals called hormones … also help the body respond to stimuli

Body Systems & Human Health 8% of adult body is made up of blood Component% of Blood Volume Main Function plasma55%carries nutrients, waste products, hormones & blood cells red blood cells 44%carry oxygen white blood cells <1%defend body against infection & disease platelets<1%cause blood to clot at wounds to prevent blood loss

Disorders in Human Body Systems SystemDisorders Digestivelow fibre, high fat, to much sugar, to much salt, smoking, alcohol, etc can cause problems such as ulcers in stomach, bowel disease, cancers, etc. Respiratorysmoking and pollution irritate lining of lungs resulting in cough & difficulty breathing; can lead to lung cancer Circulatorydisorders of circulatory system are the leading cause of death in North America most common problem is high blood pressure which affects circulation and can lead to heart attach (damage to heart muscle) and strokes (brain damage) smoking, poor diet, and lack of exercise contribute to the problem