Bio 11: Unit 1 Test

Taxonomy

Science of classifying Living Things

Purposes of Taxonomy

1. To help identify organisms

2. To represent relationships between organisms

Domains/Superkingdoms

• Eukarya (Eukaryotes)

• Bacteria (Prokaryotes)

• Archaea (Prokaryotes)

Levels of Classification

Characteristics become more similar as you move down

1. Domain

2. Kingdom

3. Phylum

4. Class

5. Order

6. Family

7. Genus

8. Species

Kingdoms

1. Plantae

2. Animalia

3. Protista

4. Fungi

5. Archaebacteria

6. Bacteria

Binomial Nomenclature

Used for naming organisms

• Originate from Latin or Greek Words

• Based on Characteristics

Binomial Nomenclature System

1. Genus (capitalized)

2. Species (lower case)

Dichotomous Key

Device that can be used to easily identify an unknown organism

Two Major Cell Types

1. Prokaryote Cells - eg. bacteria

2. Eukaryote Cells - eg. animals, plants, fungi, protists

Eukaryote Cells

• Larger in size

• Complex Internal Organization

• Contains membrane bound organelles

• Has true nucleus

Prokaryote Cells

• Smaller in size

• Simple internal organization

• No true nucleus (has nucleoid; single loop of DNA)

• No membrane bound organelles

Organelle

Highly organized structure with a specific function within the cell

Cell Membrane

• Separates interior from exterior

• Controls movement of substances in and out of the cell

Cytoplasm

• Gel like material, composed mainly of water and dissolved material

• Environment where chemical reactions occur

Nucleus is composed of…

1. Nuclear membrane

2. Chromosomes (DNA)

3. Nucleolus

Nuclear Membrane

• Surrounds genetic material

• Nuclear pores, allow material to move in and out

Chromosomes (DNA)

Provide instructions to make living things

Nucleolus

Makes parts to assemble ribosomes

Ribosome

• Cluster of ribosomes = polyribosomes

• Help construct polypeptides (proteins)

• When free makes proteins for cytoplasm

• When membrane-bound makes proteins to be exported out of cell

Endoplasmic Reticulum

• connected to nuclear membrane

• Rough ER has ribosomes attached, produces proteins to be transported via vesicles

• Smooth ER, no ribosomes attached; produces lipids used to transport other products to different locations via vesicles

Golgi Apparatus/Body

• Stack of flattened membrane bound sacs

• Factory of cell

• Receive products from endoplasmic reticulum, products are modified stored, and shipped to where they are needed

Mitochondria

• Provide cell with energy by breaking down carbohydrates

• Can make copies of itself with increased demand

• Inner folds called Cristae

• Has its own DNA to make specific proteins

Lysosome

• Single membrane sack containing digestive enzymes

• Used to breakdown worn out cell components

• Recycles materials

Peroxisome

• Breaks down fats and lipids

• Converts toxic waste products to less harmful substances

Vacuole

• small fluid filled sac

• Larger in size than a vesicle

• Can store water and dissolved substances

• Others store food

Cytoskeleton

• Network of fibers that crisscross through cytoplasm

• Helps to support and maintain the shape of the cell

• Provides rails for organelles to move along

ANIMAL CELLS ONLY

Cilia:

• Arrangement of many, short microtubules

• Used for movement

Flagella:

• Arrangement of 1-2 long microtubules

• Used fir movement

Centrosome (pair of centrioles)

• Microtubules arranged in special ring-like structure

• Involved in separation of chromosomes during cell division

PLANT CELL ONLY

1. Cell Wall

• Composed of cellulose fibers (add strength and rigidity)

• Gaps called “plasmodesmata” allow movement of substances between neighboring plant cells

2. Plastid

• single membrane bound structure that stores starches, lipids, or proteins

• Often needs light to trigger a reaction

  • Eg. Chloroplast

3. Central Vacuole

• One large vacuole present (single membrane)

• Stores water to help maintain “turgid” state

How does Chloroplast work?

• Contains chlorophyll (pigment) that capture energy from sunlight and use it to make food for the plant

• Has it’s own DNA

Function of Mitochondrion

To carry out reactions of cellular respiration

Cellular Respiration

Series of reactions that make ATP (form of energy that cells use in living things)

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy (ATP)

Appearance (Structure) of Mitochondrion

1. Contains two membranes

• Smooth outer membrane

• Highly folded inner membrane

• Inner membrane provides locations for proteins that help make most ATP molecules (increased SA allows for more reactions to take place)

2. Center of the structure is protein rich fluid called the matrix

Function of Chloroplast

Carry out the reactions of photosynthesis

Photosynthesis

Series of reactions that help make food for plants and some bacteria and protists. Food can be stored and used as starting materials for cellular respiration.

6CO2 + 6H2O → C6H12O6 + 6O2

(Reverse reaction of Cellular Respiration 😉)

Structure of Chloroplast

Contains two membranes:

1. Outer membrane

2. Inner membrane

Center of the structure: there are stacks of thylakoids that contain pigments such as chlorophyll

Fluid Mosaic Model

“Fluid”

• Components of the membrane are able to move laterally

“Mosaic”

• A collage of many different proteins, lipids, and carbohydrates

Cell Membrane Structure (4 Parts)

1. Phospholipids

2. Membrane Proteins

3. Membrane Carbohydrates

4. Cholesterol

Phospholipids

• Phospholipids bilayer:

  • Composed mainly of phospholipids with the following structure

  • Polar head (phosphate) → hydrophilic (like water)

  • Non-polar Tail (2 fatty acid chains) → hydrophobic (hate water)

Membrane Proteins

1. Integral proteins (Transmembrane proteins): Proteins that are inserted into the membrane

2. Peripheral proteins: Proteins attached to the surface of the cell membrane

Functions of Membrane Proteins

1. Transportation

2. Enzymes

3. Receptor sites

4. Cell adhesion

5. Attachment to the cytoskeleton

Membrane Carbohydrates

• Glycolipids: Some membrane carbs are covalently bonded to lipids

• Glycoproteins: Most membrane carbs are covalently bonded to proteins

Function of Membrane Carbs

Cell to Cell recognition

• Allows cells to determine if other cells it meets are similar or different from itself

• Identity depends on the composition of the carb (known as “surface marker”)

Cholesterol

4 fused - rings structure embedded within the membrane

(Lil circle on rope of pentagons)

Importance of maintaining “Fluidity”

At low temps, some membranes can solidify

• Decreased permeability

• Some proteins may stop working due to their inability to move

At high temps, some membranes may become too fluid

• Increased permeability

• Large gaps can form, resulting in “leaks”

Solution to Maintaining Fluidity

• Cholesterol enhances membrane fluidity

• It wedges in between phospholipids to keep rigidity

Homeostasis

State of “steady environment” within the cell. It is assisted by Laws of Diffusion.

Passive Transport

Movement of substances across membrane without the need for energy

Types of Passive Transport

1. Diffusion

2. Osmosis

Diffusion

The movement of molecules from region of high concentration to a region of low concentration

Osmosis

Diffusion of water across a membrane separating two solutions

Isotonic

[water] in cell = [water] outside cell

Equal amounts of water move in and out of the cell

Hypotonic

Higher [solute] inside the cell than outside the cell

More water moving in. Can cause an animal cell to BURST. This is known as lysis.

Hypertonic

There is lower [solute] inside cell than outside cell. Water is moving out. Can cause the cell to shrink. In a plant cell, the cell membrane pulls away from the cell wall. This is called plasmolysis.

Facilitated Diffusion

Passive movement of a substance into or out of the cell by means of specific integral proteins embedded in the cell membrane

Carrier Proteins

Accept large non charged molecules w specific shape

Channel Proteins

Accepts charged particles to pass through the cell membrane

Active Transport

Moving substance AGAINST the concentration gradient

• Energy is required

• Many cells used about 40% of their energy on active transport

  • Kidney cells used about 90% of their energy to pump glucose and amino acids out of urine and back into the bloodstream

Sodium Potassium Pump

• Cells have high concentration of K+ on the inside and a high concentration of Na+ on the outside

• Na+ and K+ ions are moved against the concentration gradient with the help of specific membrane (integral) proteins embedded and using energy (ATP)

  • 3 Na+ move out and 2K+ move in

Bulk Transport

• Requires the formation of vesicles to “swallow” or “Expel” material

• Requires energy

Two types of Bulk Transport

1. Endocytosis (to take in)

2. Exocytosis (to expel)

Types of Endocytosis

1. Pinocytosis

2. Phagocytosis

3. Receptor-mediated

Pinocytosis

• “Cell Drinking”

• Intake of small droplets of E.C.F and dissolved particles

• Occurs in nearly ALL types of cells, all of the time

Phagocytosis

• “Cell Eating”

• Intakes large droplets of E.C.F and large particles (such as bit of organic matter or bacteria)

• Occurs only in specialized cells (eg. Amoeba)

Receptor - Mediated Endocytosis

• Intake of specific molecules that attach to receptors (proteins on the surface of the cell membrane)

  • Eg. Intake of cholesterol

• Occurs when a cell requires lots of the same particles for important cell functions

Exocytosis

• Reverse of Endocytosis

• Vesicles from inside the cell move to the cell surface

• Vesicles fuse with membrane, open up and release its contents to the E.C.F

Viruses need to be in _____ (___) to survive and reproduce

Host

Characteristics of Living Things

1. Reproduction

2. Growth

3. Metabolism

4. Death

5. Adaptation

6. Response to Stimuli

7. Locomotion

Viruses: Alive or Not

Viruses do not have Metabolism or Growth: they do not have te cell components for it

Can Viruses Reproduce?

Yes, they can reproduce but just not on their own

→ They need to use a living cell’s “machinery” to reproduce

General Features of a Virus

• Very small, 20 to 400nm in size

• Consists of an inner nuclei acid core (DNA or RNA)

• Comes in various shapes

Structure of a Virus

2 Main Parts:

1. Core - Nucleic Acid → Genome

2. Shell - Protein Coat → Capsid

Some viruses have:

3. Envelope - Lipid membrane → covers the capsid

4. Spike - Glycoprotein → attach to host cell surfaces

Host Range

Each virus has a specific group of hosts that it can infect

• Can be broad or very narrow

How does a virus infect? (ASAR)

1. Attachment : Virus recognizes a host cell and attaches to it, then injects its nucleic acid into the host cell

2. Synthesis: Viral nucleic acid directs host cell’s machinery to make viral components

3. Assembly: Viral components come together to make new viruses

4. Release: New viruses are released from infected host cell’s machinery. This is referred to as lysis of the host cell, and it dies.

Types of Replication Cycles

Lyric cycle : virus infects host and makes more viruses right away

Lysogenic cycle: virus coexists with cell (virus remains dormant)

NOTE: Lysogenic cycle will eventually enter the lyric cycle

Lysogenic Replication (ARBA)

1. Attachment

2. Recombination: Viral genetic material combines with host genetic material

3. Bacterial Cell Reproduction

4. Activation of Lytic Cycle by “Trigger”

Types of Viruses

• DNA viruses

• RNA viruses

  • Retroviruses

DNA Viruses

• Genome is double stranded

  • Mutations are minimal

  • Maintains its identity

• Your immune system will always recognize this virus

• Can carry out Lysogenic cycle

  • It remains dormant in the nucleus of host cell

Example of DNA viruses

1. Human papilloma virus

2. Herpes viruses

RNA Viruses

• Genome is single stranded

  • Mutations can be permanent change

• Due to mutation, your immune system may not recognize the new mutated virus

  • New antibodies need to be made

• Can NOT carry out Lysogenic cycle

  • as this would need DNA to remain dormant in the nucleus of the host cell

Examples of RNA Viruses

1. Rhinoviruses (Common cold)

2. Influenza (The Flu)

3. Rotaviruses (Stomach Flu)

Subgroup of RNA Virus: Retroviruses

• Contain an enzyme (reverse transcriptase) that allows them to convert their RNA to DNA

  • Makes it able to carry out the Lysogenic cycle

• Can mutate and lay dormant within host cells

  • Are more dangerous than some DNA viruses and non-retro RNA viruses

Example of Retroviruses

1. HIV

2. Hepatitis B

What causes symptoms?

Destruction of host cells

What is a Vaccine?

• Substance that contains non-infectious virus particles

• Causes the body to react and make antibodies against this virus

• The body is now ready to fight infection from the REAL virus

Why are Vaccines Important?

They break the path of transmission making sure the virus is unable to infect cells, make copies of itself and therefore infect other hosts

Herd Immunity

If most members of a population get vaccinated, then individuals unable to be vaccinated (due to allergies, religion etc.) are also protected

Can Antibiotics be Used?

NO!, Antibiotics target organelles, therefore they DO NOT kill viruses

How do Anti-viral Drugs Work?

1. Prevent attachment to host cell

2. Block entry into host cell

How can viruses be useful in Biotechnology?

• Useful tools for genetic engineering

  • Can be used to transport a “gene of interest” into a host cell’s genome

Function of DNA

Determines the characteristics of living things

Function of RNA

Direct protein synthesis within the cell

Function of ATP

Energy carrier within the cell

Bases in DNA

Adenine, Guanine, Cytosine, Thymine

Bases in RNA

Adenine, Guanine, Cytosine, Uracil

Prokaryotes can be classified based on…

1. Shape

2. Arrangement

3. Cell wall structure

4. Energy source

Shape

1. Cocci (round); singular - coccus

2. Bacilli (rod shaped); singular - bacillus

3. Spirilli (spiral); singular - spirillum

Arrangement

1. Diplo - pair

2. Staphlo - clusters

3. Strepto - chain

Gram - negative

• Thin peptidoglycan protein layer and outer membrane

• Stains pink

Gram - positive

• Thick peptidoglycan protein layer

• Stains purple

Two Main Types of Energy Source

1. Autotrophic : makes own food

• Photosynthetic → use light to produce food

• Chemosynthetic → obtain energy from inorganic compounds (only prokaryotes do this)