Cells, Tissues, Organs and Systems
Overview
Cells –
- determine if cells are alike
- describe how living things made of a single cell are able to survive
- recognize how cellar eorganized into systems
- use a microscope to observe and draw plant and animal cells
Animal Systems
- recognize that animals are made of one cell or groups of specialized cells
- use a microscope to observe and record how a single cell animal moves/feeds
- question and find answers on how the cells in your body are organized
Plant Systems
- recognize that plants are made of one cell or groups of specialized cells
- identify the structure and function of cells in plant tissues
- experiment and observe how water moves n a plant
- record observations on diffusion
- predict how plants can survive in different environments
Characteristics of Living Things (pg .8)
Copy the 6 characteristics of living things into notebook
1. Living things are composed of cells – all cells are similar with some minor differences
2. living things reproduce, grow and repair themselves – reproduce by dividing in two, cells are
needed for growth and repair
3. living things require energy – plants get energy from sun, animals from plants or other animals
4. living things respond to the environment
5. living things have a life span – exist for ltd. Period of time
6. living things produce waste
Homework: Q3, Q4 on page 9
Experiment –
Write up experiment on page 10 – Using the Microscope
Plant and Animal Cells
Animal Cell Structures
- Control: Nucleus – control centre that directs all cell’s activities
- Control: chromosomes – found inside nucleus, contain genetic information
- Materials: cell membrane – acts like a gatekeeper, controls movement of nutrients and waste
- Materials: cytoplasm – watery fluid, allows materials to be transported quickly between structures
in the cell, stores wastes
- Materials storage: vacuole – filled with fluid used to store water and nutrients
Plant Cell Structures
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- Materials storage: vacuole – filled with nutrients but takes up larger part of cytoplasm
- Protection: cell wall – protects and supports plant
- Food production: chloroplasts – contain chlorophyll that allows plants to make its own food
Structures for Movement
- Movement: flagellum – whip like that that helps cells to move
- Movement: cilia – tiny hairs that work together to move a cell
Experiment – Comparing Plant and Animal Cells
Cells in their Environment (p.20)
Cell Membranes
- cells allow some materials to leave but not others
- PERMEABLE - permitting passage
- IMPERMEABLE – not permitting passage
- SELECTIVELY IMPERMEABLE – passage of some substances but not others
Diffusion
- refer to fig 2 on page 20
- class activity of moving across the center of the class
- DIFFUSION – movement of molecules from an area of high concentration to an area of lower
concentration
Diffusion and Cells
- a way that substances move into and out of cells
- molecules of the substance will diffuse across the cell membrane from high concentration to an area of
lower concentration
- diffusion continues until concentration is the same inside and outside the cell
Homework: page 21. Q1, Q2, Q3
Osmosis
- has anyone ever had celery that is limp?
- discuss why you think this may occur?
- OSMOSIS – movement of water across a selectively permeable membrane
- water will move in one direction in order to offset the imbalance of water concentration
Cells in Solutions of Different Concentrations
- movement of water into and out of cells is vital to living things
- Refer to fig. 3 on page 23
- SOLUTE – substance that is dissolved in another substance (ie. sugar and Kool Aid crystals)
- SOLVENT – the solution that dissolves the solvent (ie. water of Kool Aid)
- if the concentration of solute molecules outside the cell is equal to the concentration of solute molecules
inside the cell, there is no net movement of water in or out of the cell
- if the concentration of the solutes outside the cell is less than that found inside the cells, more water
molecules move into the cell
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- if the concentration of solutes outside the cell is greater than that found inside the cells, more water
molecules move out of the cell
Turgor Pressure (p. 24)
- salt affects osmosis of water
- if the concentration of water outside a plant cell is higher than inside it, water molecules enter the cell by
osmosis.
- water fills the vacuole and cytoplasm causing them to swell up and push against the cell wall
- TURGOR PRESSURE – outward pressure of vacuole and cytoplasm pushing against cell wall
- when cell is full of water, cell wall resists turgor pressure preventing more water from entering the cell
(beach ball example)
- as water leaves the cell to counteract the salt concentration, it leaves the cells and the cells shrink
Refer to fig. 5 on page 24
Homework: P. 25 Q1, 2, 3, 4, 5
How Does the Concentration of a Solution Affect Osmosis? (p. 28)
Write up the experiment.
Cells and Cell Systems
Cell Organization
- TISSUE – cells that are similar in shape and function (ie. skin is epithelial tissue)
- ORGANS – tissues that are organized into larger structures (ie. heart)
- ORGAN SYSTEMS – groups of organs that have a related function (ie. circulatory system)
Copy Fig. 2 – Levels of Cell Organization in the Human Body Chart
Homework p. 33, Q1, 2, 3, 5
Unicellular Organisms
- many livings things are composed of just one cell
- MICROORGANISM – unicellular organism (one cell’d organism)
- many microorganism cause disease but most are harmless and can be helpful (ie. yogourt)
Bacteria
- most primitive and most plentiful organism on the planet
- changed very little over billions of years
- some can make their own food or are parasitic (live off others)
- bacteria have NO nucleus, NO mitochondria, NO ribosomes
Copy figure 2- typical Bacterium
Protists
- found in water or moist conditions (ie. rotting leaves)
- have a nucleus, mitochondria and ribosomes/lysosomes
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Plantlike Protists
Diatoms
- found in both fresh and salt water,
- very unique shapes and can make their own food
- 2 thin shells
Euglena
- is like both a plant and an animal cell
- if lots of sunlight – acts like a plant cell …. If reduced sunlight – acts like an animal and feeds
upon other small cells
Copy fig. 4 on pg. 35 – Euglena
Animal Like Protists
- must feed on things that are living or were once alive
Amoeba
- changes shape as it moves
- move by stretching out a branch of cytoplasm called a pseudopod (false foot)
- pseudopod anchors to an object and rest of body is dragged – also used for feeding.
- Refer to fig. 5 on page 36
Paramecium
- used hairlike structures called cilia to beat together to create water currents that move the
paramecium
- cilia can draw food into oral groove (mouth).
-bacteria is main food source
Fungus
- include many multicellular organisms such as mould, mushrooms
Yeast
- does not have chlorophyll and must rely on other organisms for their source of energy
Homework: P. 37, Q1, 2, 3, 4, 6
The Need for Cell Division
- eventually, every cell reaches a size at which it must divide
Is Smaller Better?
- before the nucleus can tell the organelles in the cytoplasm what to do, it must first receive messages from
the cell’s surroundings
- the bigger the cell, the longer it takes for messages to reach the nucleus
- cells also need a constant supply of nutrients to work well
- osmosis and diffusion need to work constantly and the cell membrane needs to be working efficiently
- amount of cell membrane can be described in terms of the surface area of the cell
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Some Big Some Small
- cells that must do a lot of work are usually smaller than cells that are not as active
- more active a cell is, more nutrients it needs and more wastes it produces
- many small cells together are more efficient at exchanging nutrients and waste than one large cell
because of a greater surface area
Cell Specialization
- unicellular organisms are not specialists
- multicellular organism benefit from cell specialization
- CELL SPECIALIZATION – every cell has a function that it is designed to perform, therefore cells in
the same organisms come in a variety of sizes and shapes
‘thin walled’ plant cells found in flexible tissue such as leaf, flower
‘thicker walled’ plant cells are specialized for support and are flexible
‘thickest walled’ plant cells provide rigid support and can make it difficult for nutrients to enter cells
From the Ground Up (p. 46)
Water Absorption
- most plants get water from the soil
- root hairs are tiny extensions on the surface of the cells
- these root hairs increase the surface area of the cell membrane which allows water and nutrients to
pass.
Tubes for Transport
- plants have tubes called xylem vessels to transport water
- Copy fig. 2 from page 47 and include the explanations
Moving Water Around
1. Root pressure – root cells pull minerals and with the minerals come water from the soil which
enters the cells through osmosis
2. Capillarity – liquids cling to the sides of narrow tubes and can help water move up inside the xylem
3. transpiration – water molecules are attracted to each other and as they evaporate for the leafs, the
pull water molecules up behind them.
From the Leaves Down
- phloem moves sugars from leaves to stems/roots for food storage
- consist of living cells
Examining the Leaf
Copy Figure 1 into notebook.
Protection:
1. cuticle – waxy coat that covers the leaf, stops water from evaporating from cells below
2. epidermis – protects the cells below, make the waxy cuticle, have no chloroplasts
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Photosynthesis:
1. palisade – layer of cells just under the epidermis, contain many chloroplasts, therefore performs
photosynthesis
Transport:
1. xylem & phloem tissue are transportation. Move water and sugar throughout cells/plant
Gas Exchange:
1. inside the plant – cells absorb air from air space below the palisade cells and release oxygen into
these spaces as well
2. inside and out the plant – stomates are controlled by guard cells, guard cells act like doors. If lots
of water, guard cell swells up and opens the stomates. If little water, guard cells relax and stomates
close
Test time!!!!!!!!
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