Biology Grade 10 Study Notes

2.1: Plant and Animal Cells

• 3 Ideas of Cell theory:

  1. All living things are made of 1+ cells

  2. Cells are the simplest unit that can carry out life processes like growing or reproducing

  3. Cells are created from other cells and cannot come from non-living matter

What is Scientific Theory?

• An idea tested with proof and developed/verified by the scientific community

Types of cells

Prokaryotic Cells:

Do not contain a Nucleus or other membrane-bound organelles.

Types of Prokaryotes:

• Bacteria

• Archaebacteria

Eukaryotic Cells:

Contain Nucleus and other organelles each surrounded with a thin membrane.

Types of Eukaryotes:

• Animals

• Fungi

• Plants

• Protista

Have organelles.

Cell structures that perform a specific function for the cell.

Cells need organelles to perform activities such as:

• Take materials from the environment

• Store materials

• Get rid of waste

• Move substances to where they are needed

• Reproduce

Similarities of both types of cells:

• An outer membrane

• DNA

• Ribosomes

• Duplicate to produce offspring

2.2: Cell Organelles:

Cell Membrane:

• Cell is surrounded by a double layered cell membrane

Function:

• Control what enters and leaves the cell

• To allow some substances to enter while keeping others out

Cytoplasm:

• All organelles inside the cell are held in the Cytoplasm

• Is made up of mostly water and some other substances

Function:

• Temporarily stores material

• Many chemical reaction take place in this organelle

Nucleus:

• Contains the cell’s genetic information called chromosomes whihc are composed of DNA

• The Nuclear Membrane separates the nucleus from the rest of the cell

Function:

• It is the control center of the cell

• Directs all the cell’s activites

DNA (deoxyribonucleic acid):

• Contains all the genetic information in the nucleus

• Carries coded instructions of all cell activity

• When a cell divides, the DNA is copied so that each new cell has a complete set of DNA

Mitochondria:

• “Powerhouse of the cell”

• Cells contain multiple of this organelle

• Multiple mitochondions are usually found in the muscle cell

Function:

The mitochondria is sometimes referred to as the powerhouse of the cell because they provide the cell with energy from glucose (sugar) through a process called cellular respiration

Word Equation: Glucose + Oxygen = Carbon Dioxide + Water + Energy

Endoplasmic Reticulum:

• Three-dimensional network of branching tubes

• It extends throughout the cytoplasm from the nuclear membrane to the cell membrane

2 types:

• Smooth (SER) - No ribosome attached

• Rough (RER) - Ribosomes attached

Function:

• A transporting system; materials such as proteins can move from one location to the other inside the cell via the ER

• Chemical reactions occur here as well

Ribosomes:

• Found on the ER or free in the cytoplasm

Function:

• Proteins are made on this organelle

Golgi Bodies (Golgi Apparatus):

• Composed of many membraneous flattened “sacs”

Function:

• Stores, modifies, and packages proteins

• Transports proteins around and out of cells using vesicles

Plant Cells ONLY:

Cell Wall:

• Outside of the cell membrane

Function:

• Provides support and protection from physical injury

Chloroplast:

• Contains green pigment called chlorophyll that gives plant leaves their green colour

Function:

• Absorbs light energy which is used in photosynthesis

Word Equation for Photosynthesis: Carbon Dioxide + Water + Energy = Glucose + Oxygen

Vacuole:

• Plants usually have 1 large vacuole which takes up most of the space inside the cell

Function:

• Hold water and other materials

• When full of water, turgor pressure keeps the cells swollen which keeps the plant’s stems and leaves firm

2.3: Mitosis

1. Interphase (90% of the cycle)

   • Interphase is the longest stage of the cell cycle

   • DNA replication and growth

   • Prepares for mitosis

   • Cells doing their everyday job

2. Prophase

   • Long strands of DNA condense into a compact called chromosomes

   • Chromosome: 2 sister chromatids held together by a centromere

   • Nuclear membrane breaks down

   • Centrides move to opposite poles

3. Metaphase

   • Chromosomes line up in the middle of the cell

   • Nuclear membrane dissolves completely

4. Anaphase

   • The centromere splits and sister chromatids separate

   • They are now called daughter chromosomes

   • They move to the opposite ends of the cell, pulled by spindle fibres

5. Telophase

   • Daughter chromosomes become thinner

   • New nuclear membrane forms around each group of daughter chromosomes

6. Cytokinesis

• Cytoplasm divides

• 2 Identical daughter cells are formed

Animal Cell: Cell membrane pinches in at the equator, forming cleavage furrow.

Plant Cell: Cell plate forms where new cell wall is laid down

2.4: Cancer

What is it?

• Cancer is uncontrolled, unregulated growth of cells

• Cells are going through the cell cycle too quickly

Reasons for cell division:

• To grow

• To repair and replace dead cells

• Cancerous cells divide repeatedly out of control even when not needed

• They crowd out normal cells and function abnormally

• They can also destroy the correct functioning major organs

Tumours:

Benign - Mass of cells that don’t affect surrounding tissues

Malignant - Mass of cells that interfere with the function of neighbouring tissues

Causes of Cancer:

• Mutation in DNA

• Carcinogens - Smoking, exposure to sun, radiation, and toxic chemicals

Screening/Diagnosing Cancer:

• Self Examinations: Breast, testicular, skin cancers

• PAP test - Cervical Cancer

• X-ray (mammogram) - Breast Cancer

• Ultra sounds - To view heart and liver tumours

• CAT and MRI

• Endoscope - Colon Cancer

• Biopsy - Surgical removal of tumour cells

• Stem cell transplant

• Immunology

2.5: Hierarchy of Structure:

Hierarchy: A system of organization in which people and groups are ranked one above the other according to status of authority

Tissue: A group of cells that have a similar structure and that function together as a unit and contain many types of cells.

Organ: A part of the body that performs a specific function

Organ system: A group of organs that work together to perform one or more functions

Cellular differentiation: The process during in which unspecialized young cells reach their mature specialized form and function.

Types of Tissues:

Epithelial:

• Thin sheets of tightly packed cells

• It is protection from dehydration

• Low friction surfaces

• Example: Lining of the digestive system

Connective:

• Various types of cells and fibres held together by a liquid

• It’s function is to support and be insulation

• Examples: Bone, Tendons, Blood

Muscle:

• Bundles of long cells called muscle fibres

• Function - Movement

• Examples: Heart, Muscles that make bones move and that surround the digestive tract

Nerve:

• Long, thin cells with fine branches at the ends capable of conducting electrical impulses

• Function - Sensory

• Examples: Brain and nerves in the sensory organs

2.6: Stem Cells:

What are stem cells?

Stem cells are cells that are not yet specialized and that are in the process of differentiation. The body is made up of about 200 different kinds of specialized cells like muscle cells, nerve cells, fat cells, and skin cells.

Why are stem cells special?

Stem cells can self-renew to make more stem cells or differentiate into a specialized cell type

Pluripotent (Embryonic stem cells): Stem cells that can become many types of cells in the body

• Get donated from embryos

• Can be grown indefinitely in the lab at an unspecialized state

• Can specialize into many different tissue types

Multipotent (Adult stem cells): Stem cells that can become only a few types of cells

• Reside in most tissues of the body where they are involved in repair and replacement

• Can only give rise to specific cell types

Induced Pluripotent Stem Cells (iPSC)

• Get from adult cells in 2007 - recent discovery

• Can be grown indefinitely in culture in an undifferentiated state

• Similar properties to embryonic stem cells (pluripotent) and can differentiate into many tissue types

• Can create stem cells directly from a patient for research

What makes stem cells so valuable?

Cell therapy → Cell-based therapy: Transplantation of specific cells and precursors

Research → Genetic, molecular, and biologic control of tissue growth and development

→ In understanding the function of genes and proteins

New drugs → Early efficacy and toxicity screening system for drug and chemical development

2.7: Digestive System

• Organ system that takes in food, digests (break down) food, absorbs nutrients and excretes (get rid) of waste

• Composed of digestive tract and accessory organs

• Digestive tract – long tube with 2 openings

• Ex. Earthworm

• 2 types:

  • Mechanical digestion

    • physical break down of food into small molecules through chewing

  • Chemical digestion

    • chemical break down of food into small molecules using enzymes (chemicals that speed up chemical reactions)

Mouth:

• Starts the breakdown of the food

• Mechanical digestion - Using teeth and tongue

• Chemical digestion - Saliva

• Saliva softens the food and teeth breaks the food into smaller pieces

Esophagus:

• Muscular tube connecting mouth to stomach

• Composed of smooth muscle tissues that pushes food down to stomach

Stomach:

• Holds and mixes the food

• Cells in the stomach lining produces enzymes and hydrochloric acid (HCl)

• pH 2-3

• Stomach is protected from HCl by mucus lining

• Chemical digestion of food

• Food mixture is called chyme

Small Intestine:

• Chyme from stomach enters small intestines

• Over 6-7 m long

• Goblet cells produce mucus

• Produces enzymes for chemical digestion

• Food is completely broken down; nutrients are absorbed

Large Intestine:

• 1-2 m long

• Absorbs water from indigestible food

• Waste is excreted as semi-solid\

Liver:

• Produces bile

  • fluid that breaks down fats

• Detoxification

  • converts alcohol and drugs into soluble waste

Gallbladder:

• Pouch located underneath the liver which stores bile

Pancreas:

• Located underneath the stomach

• Produces enzymes for chemical digestion

• Produces insulin (hormone) that regulates the sugar level in blood

Digestive system disorder:

Ulcers

• Stomach lining breaks down and stomach cells are exposed to HCl

• Could lead to cuts and holes in stomach

• Causes: bacteria, diet, stress

• Treatment: antibiotics

2.8: The Circulatory System

Functions:

• Transports substances around the body

• Transports white blood cells to infected body parts

• Regulates body temperature

The Circulatory System consists of Blood, Blood Vessels, and Heart

Components of Blood:

Erythrocytes (red blood cells)

• 45% of blood volume

• Flattened disk shape

• Does not have a nucleus

• Contain a protein called hemoglobin – transport oxygen to cell

Leukocytes (white blood cells)

• Less than 1% of blood volume

• Many different types

• Contain nucleus

• Fight off infections

Platelets

• Less than 1% of blood volume

• Tiny cells that help in blood clotting

Plasma

• Liquid part of blood

• 55% of blood volume

• Contains proteins, vitamins, minerals, ions

Blood is made from stem cells bone morrow

Main types of blood vessels: Arteries, Veins, Capillaires

Arteries

• Arteries take blood __A__WAY from the heart

• Must withstand high blood pressure, therefore walls are very thick

Veins

• Veins bring blood BACK to the heart

• Lower blood pressure therefore walls are not as thick as arteries

Capillaries

• Walls are very thin

• Oxygen and nutrients diffuse from blood into body cells

• Carbon dioxide and wastes diffuse from body cells into blood

• The entire body is covered with a network of capillaries

The Heart:

• 4-chambered pump that moves blood around the body

Composed of :

• Cardiac muscle tissue

• Nerve tissue

• Connective tissue

• Epithelial tissue

• Blood flows from top chambers (atria) to bottom chambers (ventricles) and right side to left side

• When cardiac muscle contract the heart beats

• Heart beat changes. When?

  • Physical activity

  • Temperature

  • Stress

  • Drugs

Circulatory system diseases:

Coronary artery disease

• Coronary arteries carry blood that provides oxygen and nutrient to the heart

• These blood vessels can be blocked with fat, blood clots and reduce blood flow to heart

• Can lead to heart attack

Causes:

• Tiredness

• Dizziness

• Chest pain

• Shortness of breath

• Nausea

Symptoms:

• Tiredness

• Dizziness

• Chest pain

• Shortness of breath

• Nausea

Diagnosis:

• Angiogram – X-ray image of heart

• Electrocardiogram (ECG)

Treatments:

• Drugs

• Bypass surgery

2.9: Respiratory system

Functions:

• Provides the cells with O2 and removes CO2 from cells

• Works with the circulatory system to move O2 and CO2

Nasal passage:

• Passageway is lined with hairs and mucus

• Act as a filtering system; cleans the air

• Warms the air

Pharynx:

• Back of the mouth-throat

• Leads to esophagus or trachea

Epiglottis:

• Flap covering the trachea

• Prevents food from entering trachea

Larynx:

• Vocal cords

• Produces sound

Trachea (windpipe):

• Moves air down to lungs

• Supported by cartilage rings

• Lined with ciliated (microscopic hair), epithelial cells

• Cilia sweep particles out - coughing

Bronchi and bronchioles:

• Trachea leads to bronchus (pl. bronchi), which further divides into smaller bronchioles

• Supported by cartilage rings

• Moves air along respiratory pathway

Alveoli:

• Bronchioles eventually branch into alveoli

• Thin-walled, tiny air sacs

• Covered with blood capillaries

• The alveoli provides a huge surface area in the lungs for gas exchange

Gas exchange:

• O2 diffuse from alveoli into capillaries

• CO2 diffuse from capillaries into alveoli

Lungs:

• Houses the bronchi, bronchioles and alveoli

• Right lung has 3 lobes

• Left lung has 2 lobes (to accommodate the heart)

Diaphragm

• Dome-shaped sheet of muscle, underneath the lungs

• Contracts and relaxes to change the volume of the lungs when breathing

Breathing:

• Movement of air into and out of the lungs

Inhalation – movement of air into the lungs

• Diaphragm flattens and intercostal muscles contract

• lung volume increases; the pressure decreases

• air moves into the lungs

Exhalation – movement of air out of the lungs

• Involves the diaphragm and intercostal muscles (ribcage)

• diaphragm is dome-shaped and intercostal muscles relax

• lung volume decreases; the pressure increases

• air moves out of the lungs

Control of Breathing:

• Breathing is involuntary

• Controlled by a part of the brain that detects [CO2]

• ↑ [CO2], brain sends an impulse to the diaphragm, intercostal muscles and heart to ↑ breathing and heart rate