part of my grade 11 biology notes

8/3/2019 Part of my grade 11 biology notes

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Gr.11 Biology notes

Biology is the study of life. It examines the structure, function, growth, origin, evolution,

and distribution of life.

Levels of biological organization:

Atoms Molecules (organic/inorganic) Cells Tissues Organs Organ

Systems Organism Population Community Biomes Biosphere

Unit 1: Cellular functions

Cellular functions are functions that cells carry out. How do cells function?

Dependent on organic and inorganic molecules ex. DNA, carbohydrates, salt etc.*Note: Organic molecules have to have C+H. Inorganic molecules are all else

The study of biological molecules, chemical reactions, and the processes involved in

chemical reactions is Biochemistry

Cellular Respiration is an essential chemical reaction:

6O2 + C6H12O6 6CO2 + 6H2O + Energy

This reaction provides energy for cells to carry out

functions

In chemistry, there are three types of bonds:

Ionic: when atoms give or take electrons to form ions

In these diagrams, partial charges are shown in yellow. In Boron Trifluoride, the

charges are equally distributed. However, in water they are not. Boron Trifluoride is an

example of symmetrical attraction and water is an example of non-symmetrical

attraction. Boron Trifluoride is non polar and water is polar.


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Covalent: attraction between + and -, repulsion - and -, + and + Rate of attraction

increases faster than that of repulsion. Electron shells meld and each atom stable

PolarCovalent: atom that has more protons pulls electrons more of the time making it

negatively charged ex. water

Because of partial charges, weak hydrogen bonds form between polar molecules

Hydrogen bonds only form between H and O, N, or F

*Note: the special symbol means partial charge

Water:

Is the most abundant molecule in any cell. It's functions are:

-To carry dissolved materials in and out of the cell

-Serve as a raw material (reactant) in many cell reactions

-Act as a lubricant between cells, tissues, and organs

-Regulate temperature

What allows it to perform these functions?

-Remains liquid over wide temperature ranges


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-

Dissolves most substances important to living processes

ex. O2, CO2, glucose, amino acid, NaCl, etc. (often called the universal solvent)

-Changes temperature gradually when heated or cooled (high specific heat capacity)

-Only pure substance to expand when solid floats when it freezes

Water is polar covalent: other water and polar molecules are attracted to it

Macromolecules:

Macromolecules are large molecules (polymers) composed of smaller subunits

(monomers) bonded together


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Four main types: Carbohydrates, Lipids, Proteins, NucleicAcids

Chemical reactions are needed to make macromolecules. They are shown in the

diagram above.

Carbohydrates:

Basic Formula: CnH2nOn, where n is any whole number (ex. glucose is C6H12O6)

Carb. functions:

-Short and Long term energy storage (ex. glucose, starch)

-Physical strength to the cell structure (ex. cellulose makes plant cell walls)

Type Basic Structure Function

Monosaccharide One monomer: simple

sugar. Generally made of 5-

6 carbon monomer

Quick source of energy

Disaccharide Two simple sugars linked Quick source of energy

Polysaccharide Many simple sugars made

up of glucose subunits

Long-term energy storage,

Structural support

*Note: the bond connecting the two sugar monomers is called aglycosidic bond

Remember the following Disaccharides:

-Sucrose (glucose+fructose)

-Lactose (galactose+glucose)

-Maltose (glucose+glucose)

On the right are three Polysaccharides.

-Starch serves as energy storage in plants-Cellulose serves as a structural molecule in plants

-Glycogen serves as energy storage in animals

Lipids


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Features:

-very diverse

-do not dissolve in water (non polar)

water hating (hydrophobic)

Functions:

-Long term energy/nutrient storage

-Insulation, cushioning of internal organs

-Hormones (chemical signals that send massages

around the body)

-Waxes (keep water in/out) ex. plants

-Helps absorb vitamins

Fats-solid at room temperature, Oils-liquid at room

temperatureboth made of glycerol and 3 fatty acids

On the right is the structure of a Triglyceride

molecule.*Note: the three fatty acids do not need to be the same

Fatty Acids may be:

Saturated: has no double bonds (present in fats)

more likely to be solid

Unsaturated: has double bonds (present in oils)

more likely to be liquid at room temperature due to

"kinked" shape

In the diagram on the right, the top two fatty acids are

saturated and the bottom one is unsaturated.

Trans fats: are unsaturated fats that have had

hydrogen artificially added to them. They are linear

and easy to pack together. Called Hydrogenation

Trans fats raise risk of heart disease:

-Raise blood levels of bad cholesterol, LDL. This is a

risk to heart disease.

-Lower blood levels of good cholesterol, HDL. HDL

protects against heart disease.


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Phospholipids-important in cell membranes

(shown in diagram on right)

-Made up of Glycerol, Phosphate, and 2 Fatty

Acids

-Head is polar (hydrophilic) -Tail is non polar(hydrophobic)

Proteins

Most diverse and complex of macromolecules

Functions:

-provide structure ex. hair, bones, muscle

-facilitate chemical reactions as enzymes ex. amylase in saliva-transports substances ex. across cell membrane, hemoglobin

in blood

-acts as a chemical messenger ex. insulin regulates glucose

Composition:

-Made up of monomers called amino acids. There are 20

different Amino Acids

-Amino Acids are linked by peptide bonds to form a

polypeptide-Polypeptide folds into a 3D structure to form a specific shape

Primary Structure Is the order of amino acids

Secondary Structure Hy drogen bonds between amino acids

Tertiary Structure Super-folding due to other bonds

Quaternary Structure Multiple polypeptides form Protein

*Note the different types of folding:Pleated sheetandAlpha helix

Nucleic Acids

Functions:

-determine what characteristics living things have ex. DNA

-direct protein synthesis within the cell


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-energy carrier within the cell

Structure:

-monomer called nucleotide (nt)

-made up of phosphate sugar and nitrogenous base

RNA is ribonucleic acid

single strand of nucleotides, each nucleotide contains ribose sugar

DNA is deoxyribonucleic acid

double stranded nucleotide, each nucleotide contains deoxyribose*Note: there are 4 different types of nucleotides

DNA: Adenine, Thymine, Guanine, Cytosine

RNA: Adenine Uracil, Guanine, Cytosine

Cell membrane:

Functions:

-acts as a barrier between cell and environment

-permits passage of selected substances in and out of cell

-flexible and able to change shape

The fluid mosaic model:

-Fluid: membranes are not static (able to move)

-Mosaic: membranes consist of a mosaic of different components scattered throughout

Cell membrane consists of:

1.Phospholipid bilayer

-two layers

-hydrophilic (water liking) region: "head"-hydrophobic (water hating) region: "tail"

-small, neutral molecules can pass through spaces in the cell membrane


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2.Proteins:

-Peripheral proteins: external / internal surface (hydrophilic)

Functions:

-Enzymes carry out steps in a metabolic pathway (reactions)

-Receptor sites, once a chemical binds, it initiates chain reactions of chemical changes

in cell

-Cell adhesion holds adjacent cells together

-Integral proteins: embedded deep in the membrane (mostly hydrophobic)

Function: -Transportation, move substances across the phospholipid bilayer

3.Cholesterol

-a type of lipid

-at low temperatures: allows for fluidity by preventing close packing of the phospholipids

-at high temperatures: maintains rigidity of the phospholipids

4.Glycolipids / Glycoproteins

-Carbohydrate chains attached to lipids and proteins-found only on external surface only


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-each type of cell has it's own unique "fingerprint" of carbohydrate chains that

distinguish it from other kinds of cells

-Glycolipids attach to Phospholipids -Glycoproteins attach to Peripheral Proteins

-Membrane carbs allow for cell - cell recognition. Allows cells to determine of other cells

are similar of different. The identity of cell depends on carb composition

Passive Transport:

The movement of substances across the membrane without the need for energy

1.Diffusion: the movement of small, uncharged particles from an area of high

concentration to an area of low concentration

2.Osmosis: Diffusion of water across a semi-permeable membrane separating two

solutions

*Note the names in the differentsolutions. Also note that for plant

cells it is normal to be in a

hypotonic solution

*Note: Concentration gradient

refers to the diffusion from areas

of high to low concentration


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3.Facilitated diffusion: Passive movement of a substance in and out of cell by

embedded proteins

-Channel proteins: Accept charged ions to pass through the cell membrane

-Carrier proteins: Accept non-charged particles with specific shape

Osmosis and diffusion lead to equilibrium

Some biological processes need to work against them

Active Transport:

-moving substances against the concentration gradient

energy is a must*Note, diffusion is not enough to provide everything for cell

-many cells use up to 40% of energy on active

transport ex. Kidneys use up to 90%

Sodium-Potassium pump:

-cells have high concentration of K+ on inside, high concentration Na+ on outside

-Na+ and K+ move against concentration gradient with help of specific membrane

protein and energy

-this process brings glucose in at a faster rate as shown on the right

Why go through all this trouble?

-facilitated diffusion bringing Na+ back into the cell

allows glucose to piggyback in


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-facilitated diffusion of glucose by itself is not enough to provide the glucose needs of

the cell

Bulk Transport:

-requires the formation of vesicles to "swallow" or "expel" material

-requires energy (active transport)

Two overall types:

-Endocytosis (take in)

-Exocytosis (expel)

Types of Endocytosis:

1.Pinocytosis:

-means cell "drinking"

-intake of small droplets of ECF (extracellular fluid) and dissolved particles

-occurs in nearly all types of cells all the time (in humans)

2.Phagocytosis:

-means cell "eating"

-intake of large droplets of ECF (such as organic matter and bacteria)

-occurs only in specialized cells ex. Ameoba, Macrophages (immune cells)

3.Receptor-Mediated Endocytosis:


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-intake of specific molecules that attach to receptors (proteins on surface of cell

membrane) ex. Cholesterol

*Note: the fluid contents still enter the cell

Exocytosis:

-reverse of Endocytosis

-vesicles form from inside cell and move to the cell

surface

-vesicles fuse with membrane, open up and release

contents to ECF

-ex. Secretory cells (Pancreas cells produce insulin)

Inside the cell:

Living cells must:

-obtain food and energy

-convert energy from external source

-construct and maintain molecules that make up cell

structures

-carry out chemical reactions

-eliminate wastes

-reproduce-keep records

Eukaryotes: have a complex internal structure

-have organelles (organized, specialized structures)

-organelles work as a team

Prokaryotes: smallest type of internal organization

-lack of a nucleus!

-DNA is concentrated in an area inside the cell called nucleoid


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Organelle Characteristics and functions

Cell membrane -fluid mosaic membrane separates cell interior from outside

-controls movement of materials in/out of the cell

-also allows for self recognition

Cytoplasm -gel like material made mostly of water contains dissolved materials-creates chemical environment for other structures

Nucleus -command centre for cell contains DNA blueprint of proteins

-surrounded by double membrane with nuclear pores

Nuclear pores -pores in the nuclear membrane to allow macromolecules enter,

ribosomes leave

Chromatin -uncoiled chromosomes (DNA)

Nucleolus -specialized area of chromatin for producing proteins

Ribosome -two subunits that construct polypeptides

-can be free or membrane bound

Endoplasmic Reticulum -rough ER: has ribosomes on surface

-smooth ER: synthesizes phospholipids and packages

macromolecules in vesicles

Golgi Body -receives vesicles from the ER

-contains enzymes for modifying proteins/lipids

-packages finished products into vesicles for exocytosis

Mitochondrion -powerhouse of the cell, organic molecules broken down into ATP

-has double membrane + DNA

Lysosome -membrane bound vesicle with digestive enzymes

-breaks down macromolecules and worn out cell components

Peroxysome -membrane bound vesicle with enzymes

-breaks down toxins, lipids converting waste into less harmful stuff

Centrosome

(only in animals)

-organelle located near nucleus

-pair of centrioles that organize cell division

Vesicle -small membrane bound transport sac

Vacuole -large membrane bound, fluid filled sac

-temporary storage of food, water, waste products


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Organelle Characteristics and functions

Cytoskeleton -network of three kinds of interconnected fibres

-maintain cell shape and allow for movement of particles

Microtubules Actin filaments Intermediate filaments

Cell wall

(plants only)

-composed of cellulose fibbers for strength + rigidity

-gaps called plasmodesmata allow movement of substances

Plastid

(plants only)

-membrane bound structure store starch, lipids, proteins

-often needs light trigger

Chloroplast

(plants only)

-chlorophyll captures energy from the sun

-has double membrane and own DNA

Photosynthesis:

Two main stages of photosynthesis

0. Photo Stage light dependent

-occurs in thylakoids

-chlorophyll absorbs light-ATP is synthesized

-water is broken to produce O2

2. Synthesis Stage light independent

(also known as Calvin Cycle)

-occurs in the stroma of the chloroplast

-ATP (from stage 1) used to make glucose molecules from CO2

Cellular Respiration Reactions:

-occurs first in the cytoplasm then in the mitochondria

First step, Glycolysis: anaerobic (no oxygen)

-glucose split into 3 Carbon molecules (pyruvic acid)

-net energy of 2 ATP


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Second Step, Fermentation: anaerobic

-no extra energy, helps recycle materials

-Pyruvic Acid converted into Lactic Acid (muscle cells) or Ethyl Alcohol (yeast)

Second Step, Citric Acid Cycle (Kreb's Cycle)

Third step, Electron Transport Chain (ETC)

34 ATP released from these processes

*Note: steps two and three of aerobic respiration occur in the mitochondria

Unit 2: Diversity of living things

Why is it so important?

-for the health of the biosphere: the more diverse the ecosystem, the greater it's stability

Why does increased diversity increase the stability of the ecosystem?

-it provides many options and alternatives ex. There are 30 million species of insects

Intro to classification:

To understand the diversity of living things, we classify organisms

Why do we need a classification system?

-to group things in an organized way

-provides specific details to help identify organisms and represent relationships

Taxonomy:

is the science of classifying living things

It's two main purposes:

-help identify organisms

-represent relationships between organisms

Early Taxonomy:

-Aristotle proposed that all living organisms be arranged in a hierarchy


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-simple organisms at the bottom, complex at the top

Carl Linnaeus (1701-1778):

-developed presently used classification system

-system based on physical + structural features-the most features in common, the more related they are

How are things classified?

-hierarchy of groups (taxa pl. taxon sing.)

Kingdom largest, most general taxa

Species smallest taxa

Binomial Nomenclature:

-used for naming organisms by two names referred to as a scientific name

Scientific Names:

-originate from Latin/Greek words

-based on a characteristic ex. colour, habitat

Genus:

-first part of the name

-refers to a group of organisms closely related with similar characteristics

Species:

-second part of the name

-refers to a group of organisms that look alike and

interbreed

Domains or superkingdoms:

-Prokaryotes (monera)

-Eukaryotes

-Archae

There are 7 levels of classification:


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Kingdom Phylum Class Order Family Genus Species

-Characteristics are more similar as you move down the chain.

-The smaller the taxon, the more similar are the organisms within it

5 Kingdom systems:

-plantae

-monera (bacteria)

-fungi

-animalia

-protista

-archaebacteria

Viruses:

Alive or not?

-they do not fit in the kingdom system

-they show very few characteristics of living things

-viruses need living cells (hosts) to survive + reproduce

-ex. bacteriophage, tobacco, mosaic virus, influenza, HIV

What are the characteristics of living things?

1. Reproduction

2. Growth

3. Metabolism (controlled chemical reactions ex. ingestion, excretion)

4. Adaptation

5. Response to stimuli

6. Death

7. Locomotion

Viruses are not alive

-they do not have metabolism + growth

-they do not have organelles

Structure of a virus:


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consists of two main parts

-Core: Nucleic Acid (RNA/DNA) Genome

-Shell: protein coat Capsid

Features of a virus:

-very small, 20-400 um in size

-consists of an inner nucleic acid core

-comes in various shapes

Viruses are specific Viral Specificity

-each virus has a specific group of hosts that they infect

-called host range - can be broad or narrow (depends on spikes)

Unit 4?

Respiratory Systems:

The breath of life:

-Recall: Aerobic organisms require Oxygen (O2)

-O2 is necessary for cellular respiration

Cellular Respiration releases energy to drive all cellular functions

-CO2 is the waste product of cellular respiration

Gas exchange: the process that ensures O2 enters each cell of an organism and CO2

leaves in order to meet metabolic needs of the organism

*Note: Breathing- physical forcing of air, Gas exchange- O2 coming in CO2 going out

Two gas exchange requirements:

8. Surface area: must be large enough for O2 to enter and CO2 to leave

9. Moist environment: allows gas exchange to take place (since O2 and CO2 must be

dissolved in order to be transported)

Simple gas exchange: Unicellular organisms ex. amoebae and algae

-exchange gas through membrane by diffusion


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-membrane must be moist (it must live in a moist environment)

More complex respiratory systems: Large multi-cellular organisms

-Require specialized cells greater need for O2 O2 must travel greater distances

Problems with multi-cellular life:

-The process of diffusion is only effective over a distance of a few cells

-As the body surface becomes more specialized, surface area available fro gas

exchange is reduced

Solution specialized respiratory system

Skin respiration:

-Skin must remain moist

-Skin lined with tiny capillary vessels

-O2 carried to other cells of the organism

Gills:

-Structural changes: increase surface area of the body parts involved in gas exchange

-Mechanism: has evolved which enables the organism to ventilate this surface

Fish gills:

-feathery tissue

structures consisting

of numerous

delicate branches

-ensure a large

surface area in a

limited space

- connected

to vascular

system to transportO2 and CO2 to

and from cells

Counter current gas exchange:


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Terrestrial organism gas exchange

-terrestrial organisms have an internal gas exchange system

Breathing:

-an important process as it forces O2 a cress the gas exchange surface

-relies on a basic law of physics: air moves from regions of high pressure to regions of

low pressure until equilibrium is reached

part of my grade 11 biology notes

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