Unit 2 cells and systems
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Unit 2: Cells and Systems. Topic 1: Living Organisms. Living organisms are found in all shapes and sizes, but have much in common. Living organisms: Need energy Respond and adapt to their environment Reproduce Grow Produce wastes. Functions and Structures. 1. Energy

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Unit 2: Cells and Systems

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Unit 2 cells and systems

Unit 2: Cells and Systems

Topic 1 living organisms

Topic 1: Living Organisms

  • Living organisms are found in all shapes and sizes, but have much in common.

  • Living organisms:

    • Need energy

    • Respond and adapt to their environment

    • Reproduce

    • Grow

    • Produce wastes

Functions and structures

Functions and Structures

1. Energy

  • Animals get their energy from food

  • Plants get their energy from the Sun

  • What structures do plants and animals have to allow them to gather and use food for energy?

Functions and structures1

Functions and Structures

2. Environment

- Plants move towards the Sun because they need light to make food

- Animals find food at different times during the day (ex. raccoons and deer)

3. Reproduction

- Do plants and animals reproduce in the same way? What structures enable plants and animals to reproduce?

Functions and structures2

Functions and Structures

4. Growth

- What structures enable plants and animals to grow?

- How do living organisms grow?

5. Wastes

- Plants and animals release different waste products

- Plants and animals have different structures in place to release wastes

Levels of organization in organisms

Levels of Organization in Organisms

  • Organisms have specialized structures to carry out their various functions

  • Most organisms have systems that perform certain functions to keep the organism alive

  • Systems are made of organs

    • Ex. The heart is an organ of the circulatory system

  • Organs are made from tissues

  • System -> Organ -> Tissues

    • Fig. 2.1A-C

Levels of organization in organisms1

Levels of Organization in Organisms

  • The basic unit of every system is the cell

  • Cell: the smallest unit that can perform the functions of life

  • All living organisms are made up of cells

  • The cell is the smallest thing that scientists consider to be alive

Cells work together

Cells Work Together

  • The cells in a pika’s digestive system are organized into different tissues and organs that help the pika digest plants

  • The cells in our bodies are organized into tissues and organs that help us digest a variety of foods.

Topic 2 microscopes and cells

Topic 2: Microscopes and Cells

  • Microscopes help us to see things that are too small to see with the unaided eye

  • Magnify: to make objects appear larger by using a microscope or another magnifying instrument.

A world too small to see

A World Too Small to See

  • The human eye can only see objects that are larger than 0.1mm

  • Separate dots must be more than 0.1mm apart in order for most people to see them as dots

    • Look at the circles of dots on page 103

Early microscopes

Early Microscopes

  • Anton van Leeuwenhoek (1632-1723)

  • Microscope: an instrument that makes objects appear larger by bending light through a lens

    • His microscopes were able to magnify 300X

    • He studied blood, pond water, etc

    • Was the first to observe single-celled organisms which he called “animalcules”

Early microscopes1

Early Microscopes

  • Robert Hooke (1635-1703)

    • Experimented with microscopes

    • Observed a network of tiny box-like components in the bark of an oak tree

    • Described them as “cellulae” meaning “little rooms” in Latin. This is where the term “cell” was derived.

Cells in all living things

Cells in All Living Things

  • As more scientists observed micro-organisms, they saw cells in every living thing they examined.

  • Matthais Schleiden and Theodore Schwann came up with this hypothesis:

    • All organisms are composed of cells.

    • The cell is the basic unit of human life.

    • All functions carried out by living things are carried out by their individual cells.

Cells in all living things1

Cells in All Living Things

  • Their ideas formed the basis of cell theory

  • All living things are composed of one or more cells.

  • Cells are the basic units of structure and function in all organisms.

Microscopes today

Microscopes Today

  • Compound light microscopes

    • Have two lenses, which can magnify objects 2000X

    • We use this type of microscope in schools

Microscopes today1

Microscopes Today

  • Electron Microscopes

    • Used to see smaller structures inside the cell.

    • They use beams of electrons instead of light, which bounce off the sample and form an image which is enlarged on a screen.

    • Today’s electron microscopes can magnify up to 2,000,000X

Electron microscope images

Electron Microscope Images

How to calculate field of view

How to Calculate Field of View

Medium- Low- Magnification of Low-Power Power= Power XObjective Lens

FOVFOV Magnification of Medium-

Power Objective Lens



A low-power objective lens is 4X with a FOV of

4mm. You have a medium-power objective lens

of 10X. What is the medium-power FOV?

Medium FOV = 4mm X 4


= 4mm X 0.4

= 1.6mm

Topic 3 the cell and its structures

Topic 3: The Cell and Its Structures

  • Multicellular: many-celled organism

  • Unicellular: single-celled organism

    • Although these organisms consist of only one cell, they are not simple organisms.

    • They each have a way of moving, obtaining food, and carrying out functions essential to life.

Observing plant and animal cells

Observing Plant and Animal Cells

Inquiry Investigation 2D page 118

Cell parts

Cell Parts

  • Organelles: structures inside the cell

    • Each organelle has a role to play in the activities necessary for life

  • Cell Membrane: surrounds and protects the contents of the cell, and helps control the movement of substances in and out of the cell.

Cell Membrane

Cell parts1

Cell Parts

  • Cytoplasm: jelly-like substance that distributes materials such as oxygen and foods to different parts of the cell

    • Constantly moves inside the cell

    • Helps support all other parts inside the cell


Cell parts2

Cell Parts

  • Nucleus: controls the cell’s activities

    • Contains the chromosomes (genetic material) that directs the cell’s growth and reproduction

    • Enclosed by a nuclear membrane which controls what enters and leaves the nucleus


Cell parts3

Cell Parts

  • Vacuoles: balloon-like spaces within the cytoplasm that store food, wastes, and other substances that the cell cannot use right away

    • A membrane surrounds vacuoles


Cell parts4

Cell Parts

  • Cell Wall: ONLY occurs in the cells of PLANTS, fungi, and some unicellular organisms

    • Thicker and more rigid than cell membranes

    • Made of a tough material called cellulose

    • Cell walls provide support for the cell

Cell Wall

Cell parts5

Cell Parts

  • Chloroplasts: structures in which the process of photosynthesis takes place

    • Photosynthesis uses energy from the Sun to make carbohydrates

    • Chloroplasts are only found inside cells in green plants and some unicellular organisms. NOT found in animal cells.


Cell size and function

Cell Size and Function

  • To carry out their work, cells need a constant supply of materials such as oxygen, water, and food particles, and to get rid of waste

  • Cells transfer these materials through the cell membrane

  • Cells need to be small to transfer these materials efficiently

Small smaller smallest

Small, Smaller, Smallest

  • Cells come in a variety of shapes and sizes

  • To grow larger, organisms add more cells to their bodies rather than growing bigger cells

  • This occurs when cells divide

  • Cells are measured in micrometers (μm)

    • Most cells in plants and animals have a diameter between 10 – 50 μm

Topic 4 fluid movement in cells

Topic 4: Fluid Movement in Cells

The Cell Membrane

  • Individual cells carry out the same activities as whole organisms

  • Your cells eventually make use of the air you breathe and the water you drink

  • A cell membrane allows materials to enter and leave the cell, and stops

    other substances

Cell membranes

Cell Membranes

  • Selectively permeable: a cell membrane that only allows certain materials to cross it

  • Permeable: a cell membrane that allows all materials to cross it

  • Impermeable: a cell membrane that allows nothing to cross it

  • The STRUCTURE of the cell membrane allows there to be different levels of permeability



  • The structure of the cell membrane controls what can move into or out of the cell.

  • The Particle Theory helps us to understand how particles can move through a substance

  • Diffusion: the movement of particles in liquids and gases from an area of higher concentration to an area of lower concentration.

Diffusion in cells

Diffusion in Cells

  • Diffusion also plays a part in moving substances into and out of cells

    • Example: CO2 particles move across an amoeba’s selectively permeable membrane to maintain CO2 levels in its cytoplasm

      • Figure 2.13A and 2.13B



  • The most common substance found inside cells is water

  • Water particles are small and can easily move into and out of cells by diffusion

  • Osmosis: The diffusion of water through a selectively permeable membrane



  • Water is transported through your cells by osmosis and diffusion to replace lost water in your cells

  • Water is needed by cells for dissolving many of the substances involved in cell processes

  • Water moves from a region where it is in high concentration to a region where it is in lower concentration

Measuring Osmosis Lab Investigation 2F p. 132

Fluid movement in plants

Fluid Movement in Plants

  • Plants need water for photosynthesis

  • Inside the plant, vascular tissues connect the roots to the leaves

  • Phloem tissue: transports sugars manufactured in the leaves to the rest of the plant

  • Xylem tissue: transports water and

    minerals absorbed by the root cells

    to every cell in the plant

    • Xylem tubes look like bundles of

      hollow vessels (like straws)

From root to leaf

From Root to Leaf

  • The root system of plants is covered with fine root hairs

  • Root hairs: an extension of a single epidermal cell, which protects the outside of the tissue. Water enters a root hair through osmosis when there is more water in the soil than in the root.

    • From the root hairs, water passes from cell to cell by osmosis until it reaches the xylem tube

    • As more water enters the xylem tissue, it creates pressure which pushes water up the plant

From root to leaf1

From Root to Leaf

  • Water is transported by xylem tissue into the stems and leaves

  • Leaves are the plant’s food producing organs

  • Most photosynthesis takes place in a layer of the leaf filled with chloroplasts

  • Why are leaves flat and thin?

  • There are tiny openings on the underside of leaves called stomata. They allow air to enter the leaf for respiration and photosynthesis.



  • Stomata in the leaf open and close to allow for the exit of water.

  • Transpiration: the loss of water from a plant through evaporation

    • This water loss from the leaves needs to be replaced by the roots again when the plant needs water

Pulling and pushing

Pulling and Pushing

  • Fine columns of water connect every cell of a plant, from the leaves to the roots

  • Individual water particles are held together by attractive forces, which make the plant’s water network behave as a single unit.

  • Water drawn into the roots by osmosis PUSHES water columns up the plant and water lost from the leaves PULLS water up the xylem tissues from the roots, like a pump.

Topic 5 specialization and organization

Topic 5: Specialization and Organization

  • Multi-cellular organisms have different types of cells to perform different functions for life

    • These cells are specialized: designed for a particular task

    • For example, our bodies have muscle cells, skin cells, stomach cells, nerve cells, etc.

Specialized cells

Specialized Cells

  • Humans have about a hundred different types of cells, each with its own special structure and function

  • These specialized cells have a structure that fits their function – what they’re used for

    • Ex. Nerve cells are long, thin cells. They are used for carrying nerve signals from one part of your body to another.

The advantages of being multi cellular

The Advantages of Being Multi-cellular

  • Disadvantages of unicellular organisms:

    • They have one cell that needs to carry out the function of whole organisms

    • They cannot grow very large

    • They have to take in everything they need to live from their cell membranes, so they are usually restricted to aquatic environments

Cell organization

Cell Organization

  • Multi-cellular organisms:

    • Can live in a wide variety of environments

    • Can grow very large

    • Obtain energy from a wide variety of foods

    • Specialization of cells allows cells to work efficiently

    • Are very complex, as specialized

      cells are grouped together

Cell organization1

Cell Organization

  • Plants and animals are made of TRILLIONS of cells

    • Cells with the same structure and function are grouped into tissues

    • Groups of different tissues form organs

    • Organs work together in systems

    • Systems work together to form an organism

  • The arrangement of cells, tissues, organs, and systems form several levels of organization in living things

    Cells -> Tissues -> Organs -> Systems -> Organism



  • Tissues are groups of similar cells

    • They are classified according to the functions they perform

  • Examples:

    • Muscle tissue: moves parts of the body

    • Epithelial tissue: (skin) protects the outside of the body and covers some internal structures

    • Connective tissue: (bone) connects and supports different parts of the body; can be solid or fluid

    • Nerve tissue: carries signals between brain and parts of the body to co-ordinate activities



Nerve Tissue

Epithelial Tissue

Muscle Tissue

Connective Tissue (Blood)

Connective Tissue (Bone)



  • Organs are distinct structures in the body that perform particular functions

    • Example: stomach, lungs, heart, kidneys

  • Each organ is made of several tissues working together

    • Example: Your stomach is made of four types of tissues (muscle tissues, epithelial tissues, connective tissue, nerve tissue)

      • Figure 2.24

  • Plants have organs too! Roots, stems, leaves, etc.



  • Organs work together through systems

    Cells -> Tissues -> Organs -> Systems -> Organism

  • Organs form systems which perform activities that help plants and animals function as a whole

  • Plants have fewer systems than animals



  • Plants have two main systems: a root system below ground and a shoot system above ground (stems and leaves)

  • The shoot system (stems

    and leaves) includes the

    reproductive system

    (flowers, fruit, and seeds)

Unit 2 cells and systems

  • Topic 5 Review page 144 #1-4

  • Topic 4-5 Wrap Up page 145 #1-5, 7-14

Topic 6 body systems in humans

Topic 6: Body Systems in Humans

The Digestive System

  • Digestive System: a group of organs that work together to break down food and eliminate wastes

  • Food enters the body through the mouth, then passes through the stomach and intestine

  • It is broken into small pieces that can be used by cells

  • Unused food is expelled as waste

    • Major organs: mouth, esophagus, salivary glands, stomach, liver, gallbladder, intestines, pancreas, etc.

    • Figure 2.26

Organs of the digestive system

Organs of the Digestive System

The respiratory system

The Respiratory System

  • Respiratory System: the system that moves air in and out of the body

  • Breathing in (inhalation) fills our lungs with air containing oxygen

  • Breathing out (exhalation) rids our bodies of carbon dioxide waste

    • Major organs: nose, mouth, lungs, bronchi, trachea, diaphragm, larynx, alveolus

    • Figure 2.27

Organs of the respiratory system

Organs of the Respiratory System

The circulatory system

The Circulatory System

  • Circulatory System: the system that transports food and oxygen throughout the body

  • Circulates blood through the body delivering food particles, dissolved gases, and carries away cell wastes

    • Major Organs: heart, blood, blood vessels (veins and arteries)

    • Figure 2.28

Organs of the circulatory system

Organs of the Circulatory System

How the respiratory and circulatory systems connect

How the Respiratory and Circulatory Systems Connect

  • The respiratory system exchanges oxygen and carbon dioxide, while the circulatory system transports those gases throughout the body

  • The gases pass from one system to the other in the LUNGS

  • The lungs are made up of smaller and smaller tubes

    Trachea -> Bronchus -> Bronchioles -> Alveoli

    (20mm) (12mm) (0.5mm) (0.2mm)

How the respiratory and circulatory systems connect1

How the Respiratory and Circulatory Systems Connect

  • The circulatory system also involves a series of tubes: blood vessels

    Artery -> Vein -> Capillary

  • Diffusion causes oxygen to pass from the alveoli in the lungs to the capillaries of the bloodstream

  • Each alveolus is surrounded by a web of capillaries, where gases are exchanged

  • Oxygen and carbon dioxide pass between the air in the alveoli and the blood in the capillaries

How the respiratory and circulatory systems connect2

How the Respiratory and Circulatory Systems Connect


Figure 2.30A and 2.30B

How the circulatory and digestive systems connect

How the Circulatory and Digestive Systems Connect

  • The transfer of food from the digestive system to the circulatory system takes place at the inner lining of the SMALL INTESTINE

  • Villicover the surface of this lining, and contain a network of capillaries

  • Dissolved food particles pass from the intestine into the capillaries by absorption

  • The blood stream takes these tiny food particles to your body’s cells

How the circulatory and digestive systems connect1

How the Circulatory and Digestive Systems Connect

  • Villi and alveoli both have thin walls and have millions of tiny projections (more surface area for capillaries to take gases and food without taking up space in the body!)

The excretory system

The Excretory System

  • Excretory System: the system that regulates blood composition and gets rid of waste fluids

  • Helps to filter waste materials from the blood

  • Major organ: kidneys, bladder

Sensory awareness systems

Sensory Awareness Systems

  • Our bodies are constantly responding and making adjustments to maintain a stable internal environment for our cells

    • Examples: shivering, goose bumps, sweating

  • To keep body temperature stable, our nerves, muscles, and blood work together

  • Nervous System: the body system that senses internal and external changes and controls and coordinates body activities

Sensory awareness systems1

Sensory Awareness Systems

  • The nervous system contains the brain, spinal cord, nerves, and the endocrine system (hormones)

  • The nervous system coordinates all of your body’s responses to the environment and external stimuli

Unit 2 cells and systems

Systems of the Body and their Functions

Topic 6 Review page 153 #1-6

Topic 7 body systems and your health

Topic 7: Body Systems and Your Health

Blood: The Body’s Transportation System

  • In unicellular organisms, materials are directly exchanged between the cell and its environment through the cell membrane

  • In multi-cellular organisms, most cells are not in contact with the external environment, so substances must be brought to cells and be taken away from cells by the circulatory system

Blood the body s transportation system

Blood: The Body’s Transportation System

  • In humans, substances are transported through the body via blood

    • 8% of an adult’s body weight is blood

  • Blood is made of:

    • plasma (55%)

    • red blood cells (44%)

    • white blood cells (<1%)

    • platelets (<1%)

Blood the body s transportation system1

Blood: The Body’s Transportation System

  • Plasma (liquid portion) transports most of the carbon dioxide produced by the body

  • Red blood cells are specialized to carry oxygen

    • Contains an iron-rich chemical called hemoglobin, which attracts oxygen

  • The circulatory system works closely with the respiratory system and digestive system to bring oxygen and nutrients to your cells

Blood the body s transportation system2

Blood: The Body’s Transportation System

  • If one of these systems is not functioning properly, the entire body is affected

  • Leading causes of hospitalization

    in Canada include:

    • Circulatory system 15%

    • Digestive system 11%

    • Respiratory system 10%

A healthy circulatory system

A Healthy Circulatory System

  • The heart pumps blood through your body delivering oxygen, nutrients, and food to your cells

  • Blood also carries wastesproduced by cells to other systems that can break them down or remove them from the body

  • Disorders of the circulatory system: high blood pressure (hypertension), heart attacks (damage to heart muscle), and strokes (brain damage)

Blood pressure

Blood Pressure

  • A sphygmomanometer measures

    blood pressure.

  • Blood pressure indicates several things about the health of the circulatory system:

    • Volume of blood

    • Heart Rate

    • Artery Size

    • Artery Elasticity

    • Blood Viscosity

Disorders of the circulatory system

Disorders of the Circulatory System

  • Certain conditions place people at greater risk for disorders of the circulatory system

    • Smoking

      • Nicotine constricts arteries, increasing blood pressure

    • High cholesterol

    • High blood pressure

    • Lack of exercise

    • Poor diet

      • Salt increases blood pressure, high-fat foods cause cholesterol to build up in arteries and block blood flow

A healthy digestive system

A Healthy Digestive System

  • Food provides nutrients in the form of carbohydrates, fats, proteins, vitamins, minerals, and water which provide energy and materials used for growth, development, and repair of cells.

Nutrients in food

Nutrients in Food

  • Starch and sugars (carbohydrates) provide the body with energy

    • Fruits, cereal, beans, peas

  • Fats provide us with energy and cushion organs

    • Can be stored in the body to be used when needed

  • Proteins (meat, fish, eggs) are essential for growth and help us to repair body tissues

Disorders of the digestive system

Disorders of the Digestive System

  • Colon cancer

    • Skipping meals, diet high in sugar, salt, cholesterol

  • Ulcers (stomach walls damaged by acid)

    • Caused by stress, smoking, overuse of alcohol or aspirin

A healthy respiratory system

A Healthy Respiratory System

  • Smoking, air pollution, and industrial by-products can cause serious damage to our respiratory systems

    Disorders of the Respiratory System

  • Cigarette smoke and air pollutants damage the cilia lining in our lungs, producing mucous (cough -> bronchitis -> emphysema)

  • Smoking is the leading cause of lung cancer

You and your body

You and Your Body

  • To maintain healthy organs and systems, we all need clean air and water,

    nutritious foods, exercise,

    and sleep

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