Science 10 - Biology - Part 2

Second half of bio content for science 10

Unicellular

Unicellular

One cell performs all physiological needs. Limited SA:V ratio, short lifespan.

Multicellular

Multiple specialized cells perform physiological needs. Increased overall SA, longer lifespan.

Tissue

Groups of similar cells performing a function. Ex. dermal tissue

Organ

Groups of similar tissues working to perform a function. Ex. lungs

System

A set of organs performing one or more function as a unit. Ex. digestive system

Systems - Shoot System

All parts of a plant above the ground. Consists of leaves, stem, and tubers.

Systems -Root System

All parts of the plant below the ground, excluding tubers. Areal roots above ground.

Plant Tissue - Types

1. Dermal

2. Ground

3. Vascular

4. Meristematic

Plant Tissue - Dermal (Epidermis) Tissue

Outermost layer of a plant. Used for protection, exchange of gases, and to minimize water loss. Creates (clear) waxy cuticle to minimize water loss. Includes root hairs, guard cells/stomata. No pigment (clear cells)

Dermal Tissue - Stomata/Lenticles

Openings in the epidermis to allow for gas exchange. Diffusion of gases based on concentration gradient. Lenticles apply to trees only.

Dermal Tissue - Guard Cells

Specialized cells that control access to stomata. Open/close with active transport of K+ ions into/out of cells and osmosis to become turgid or flacid.

Dermal Tissue - Waxy Cuticle

Substance secreted by the epidermis to coat leaves to minimize water loss. Clear, physical barrier to mold, bacteria, bugs, etc.

Dermal Tissue - Root Hairs

Type of dermal tissue designed to absorb water from the soil with increased SA. Creates root pressure

Plant Tissue - Ground Tissue

Second layer of tissue, underneath dermal tissue. Makes up the majority of a plant. Used for support in stem, storage in roots

Ground Tissue - Palisade Mesophyll

Tightly packed elongated photosynthetic cells on the upper surface of the leaf where the majority of photosynthesis occurs.

Ground Tissue - Spongy Mesophyll

Loosely packed photosynthetic tissue to allow for gas exchange. Multiple air pockets between the tissue.

Plant Tissue - Vascular Tissue

1. Xylem (water transport up)

2. Phloem (sugar/nutrient transport both ways)

   Also known as vein or vascular bundle

Vascular Tissue - Xylem

Cylindrical cells that form a pipeline for water to be transported from the roots to the rest of the plant, only transports water upwards. Cells are dead at maturity (less blockage for water to pass through). Allow for transpiration and adhesion

Vascular Tissue - Phloem

Cells that form a pipeline for sugars/nutrients to be transported throughout the plant. Allows for transport both ways (source to sink). Cells are alive at maturity to signal where sugars need to go. Composed of sieve tube elements and companion cells.

Vascular Tissue - Sieve Tube Elements

A phloem cell with pores on the cell wall and a sieve plate separating the cells. Lacks organelles but remains alive because of companion cells.

Vascular Tissue - Companion Cells

Small nucleated phloem cells that keep sieve tube element cells alive.

Vascular Tissue - Source to Sink

Movement of sugars to the leaves or into storage in the phloem. Can go leaves to roots or roots to leaves

1. Sugar enters phloem via AT

2. Water enters phloem via osmosis

3. Pressure build up pushes sugars through the phloem

4. Sugar moves to desired location (roots or leaves)

Plant Tissue - Meristematic Tissue

Tissue that contains undifferentiated cells in order to perform mitosis. Found in areas of plant growth. Apical meristem relates to length growing specifically.

Adaptions to Minimize Water Loss

1. Small, thick leaves to reduce SA:V ratio

2. Thick cuticle

3. Sheltered stomata

4. Shed leaves during dry months

5. Fleshy stem for water storage

Photosynthesis

Process of converting CO₂ and water into C₆H₁₂O₆ and O₂ (chemical energy) with light energy. Converts low energy reactants into high energy products in the chloroplasts of a plant cell. Glucose used for building/cell resp, oxygen used for cell resp/waste

6CO₂ + 6H₂O → C₆H₁₂O₆ + O₂

Cellular Respiration

Process of using glucose and oxygen to create energy for the cell to perform functions. C₆H₁₂O₆ + O₂ → 6CO₂ + 6H₂O + ATP

Chloroplasts

Double membrane-bound organelle that is exclusively in plant cells for photosynthesis. Made of

1. Outer + Inner membranes

2. Thylakoids

3. Stroma

4. Chlorophyll

5. Lamella

Chloroplasts - Outer + Inner Membranes

Regulates what enters/exits the chloroplasts.

Chloroplasts - Thylakoids

Disks that contain chlorophyll in a chloroplasts. When stacked, called grana/granum (plural). Where light dependent reactions occur

Chloroplasts - Chlorophyll

Green photopigment that absorbs red and blue wavelengths of light

Chloroplasts - Stroma

Thick fluid inside chloroplasts that contain the enzymes required for photosynthesis

Photosynthesis - Reaction Types

1. Light dependent - occurs in thylakoids

2. Light independent (Calvin Cycle) - occurs in stroma

Photosynthesis - Light Dependent Reaction

Reactants: H₂O, light, ADP + P_i + NADP⁺

Products: O₂ + NADPH + ATP

Occurs in the thylakoids. Uses light energy to excite electrons to make ADP + P_i + NADP⁺ high energy carriers

Photosynthesis - Light Independent Reaction (Calvin Cycle)

Reactants: CO₂, ATP, NADPH

Products: C₆H₁₂O₆, ADP + P_i + NADP⁺

Occurs in the stroma. Uses ATP and NADPH to create G3, a sugar that becomes glucose

Water Movement - Types

1. Transpiration

2. Adhesion

3. Cohesion

4. Root Pressure

Water Movement - Transpiration

Process of water vapour leaving through the stomata. Evaporation = transpiration pull. Water diffuses out of the stomata with the concentration gradient

Water Movement- Transpiration Rate Factors

1. Temperature - ↑ temp, ↑ rate

2. Light Intensity - ↑ intensity, ↑ rate

3. Wind Speed - ↑ wind, ↑ rate

4. Humidity - ↑ humidity, ↓ rate

Water Movement - Adhesion

Attraction of water molecules to molecules of other substances through H-bonds

Water Movement - Cohesion

Attraction of water molecules to each other because of H-bonds

Water Movement - Root Pressure

1. Minerals are actively transported into root cells creating higher concentration of solute inside the cell

2. Osmosis of water into cell

3. Creation of pressure inside the cell that pushes water up the roots

Tropism

Change in growth patterns of a plant based on its reaction to stimuli.

1. Phototropism

2. Gravitropism

Tropism - Phototropism

Growth of a plant in relation to light - towards the light = positive, away = negative

Tropism - Gravitropism

Growth of a plant in response to gravity - with gravity = positive, against gravity = negative

Auxin

Hormone in plants responsible for phototropism. Elongates cells on shaded sides of a plant to curve plant towards the light.

Auxin History - Darwin and son

(1880) What makes plants bend?

Discovered tip of plant shoots determine of the direction of growth. Tip of a plant was somehow communicating with the rest of the plant.

Experiment: grew plants with various parts of the plant covered

Auxin History - Peter Boysen-Jensen

(1913) How does the tip of a plant communicate with the rest?

Discovered that chemical signals that stem from the tip must be communicating with the area of elongation

Experiment: Put various barriers between tip and the rest of the plant

Auxin History - F.W. Went

(1926) What specifically is responsible for the elongation?

Discovered auxin, a hormone in plant tips, was responsible for the elongation by moving into the cells on the shaded side of a plant.

Unit D - Water Cycle

Pathway of water throughout the biosphere.

1. Condensation changes state of the water

2. Precipitation moves water from the sky onto land

3. Evaporation/Cellular Respiration/Tropism returns water into the atmosphere

Unit D - Biosphere

Layer of Earth that is capable of sustaining life.

1. Atmosphere

2. Lithosphere

3. Hydrosphere

Unit D - Atmosphere

1. Troposphere - Where the majority of weather occurs. Only layer that can support life

2. Stratosphere - Contains ozone layer

3. Mesosphere

4. Thermosphere

Unit D - Lithosphere

Solid portion of the Earth that floats on the fluid core. (Land)

Unit D - Hydrosphere

Accounts for all water on Earth, warmed mainly by the sun and partially by the mantle. Houses many organisms

Unit D - Biomes

1. Tundra - Few plants/animals, coldest biome

2. Taiga/Boreal Forest - Dominated by densely packed evergreens

3. Deciduous Forest - Moderate climate that supports diversity in organisms

4. Grasslands - Grassy region with few/no trees. AKA prairies/savannas

5. Rain Forest - Richest biodiversity in plants/animals

6. Desert - Least precipitation, organisms adapted to heat