Biology Section 3: From Cell to Organism: Focus on Plants

Tissues

Structured groups of cells working together for a specific function.

Vascular Bundle

(vein) organizes the 2 transport tissues into highways throughout the leaf

Unicellular organisms

Limited in size, need specialized cells/tissues to survive.

Division of labor

Single-celled organisms perform multiple functions, complex organisms have specialized cells.

Specialization

Cells become specialized for specific tasks in larger organisms.

Organization

Multicellular organisms are organized into (OCTOS) organelles, cells, tissues, organs, and systems.

Cuticle

A waxy covering on the surface of stems and leaves that acts as an adaptation to prevent water loss in plants.

Epidermis (Dermal tissue)

Outer layer of cells that covers all herbaceous plants

One layer thick and responsible for the exchange of matter an gases into and out of the plant (Carbon dioxide and Oxygen)

Spongy Mesophyll

Contains chloroplasts and carry out photosynthesis

Loosely packed with many air spaces around them - this structure helps in water and gas exchange with the environment

Xylem (one way)

Tissue transporting water and minerals from roots to leaves for photosynthesis.

Phloem (two way)

Transport sucrose and other dissolved sugars from the leaves to other parts of the plant. Formed from individual sieve tube cells

Peliside Cells

Main cells do photosynthesis contains LOTS OF CHLOROPLASTS

Stomata

Tiny ports created from guard cell. Stomata is used for gas exchange

Guard Cells

Regulate the size of the stomata (opening) to control H2O loss

The shape of the guard cells change to open or close the stomata

Opens through a process in which potassium ions are drawn in via active transport and water follows via osmosis, making the cells turgid

Cellular Respiration

Energy production in mitochondria, involving gas exchange.

The breakdown of glucose and other food molecules in the presence of oxygen.

Diffusion

Movement of gases through stomata and intercellular spaces.

Transpiration

Evaporation of water from the leaves of a plant, mainly through the stomata

Cohesion

Attraction between water molecules aiding in water transport.

Adhesion

Water sticking to xylem walls facilitating water movement.

Is used in plants to move water and dissolved minerals up the xylem

Root Pressure

Force moving water from roots to leaves in the xylem.

Water is forced from higher pressure roots (active transport), to the lower pressure spaces in the leaves

Works together with transpiration (evaporation of water through the leaves because as water droplets leave the plant during photosynthesis/cell resp

Another water molecule gets pulled up (by cohesion) to replace the lost water particle

Pressure Flow Theory

Explination of how a difference in turgor between sieve elements in source and sink regions pushes sugar-rish fluid through a sieve tube

Auxin

A photonegtive plant hormone that promotes cell elongation.

Is responsible for phototropism

Gravitropism

Direction of plant growth in response to gravity

Stem: negative gravitropism (grow away from gravity)

Root: positive geotropism (grow towards gravity)

Phototropism

Direction of plant growth to response to light

Stem: positive phototropism (grow towards light)

Root: weak negative phototropism (grow away from light)

Transpiration Pull

When water evaporates from the leaves of a plant, water is pulled up to replace what was lost. Effective in many ways

Turgor Pressure

The pressure inside of a cell as a cell pushes itself against the cell wall, creating a form state

organ

A collection of tissues that carry out a specialized function of the body

organelle

A tiny cell structure that caries out a specific function within the cell

Pressure difference

The force that rives movement of water throughout a plant

Ground tissue

Tissue system that makes up the majoirty of a plant

Stem - strength and support

Leaves - site of photosynthesis

Root - storage

Root Hairs

Tiny hair-like extensions that increase the surface area of the root allowing it to absorb more water and nutrients