Plant Form and Function I - (04/13)

LO 25.1: In a drawing or photograph of a plant you have never seen before, identify roots, stems, and leaves and explain their overall function; LO 25.2: Analyze the relationships among the cells, tissues, and/or organs involved in a given plant physiological system, including how their structures correlate with their functions and how they interact in terms of function; LO 26.1: Create a diagram, drawing, or model to communicate how carbon is assimilated into organic compounds in plants and relate this to the flow of energy and the synthesis of molecules required for maintenance and growth; LO 27.1: Compare the mechanisms responsible for the long-distance transport of sugars vs water and nutrients

Why do plants contain more gene than animals (being more complex than animals)?

Most genes code for enzymes. Plants have to have many more enzymes than animals because plants synthesize all of the molecules they need

Why are plants essential to understanding life?

Because they dominate Earth’s biomass and play key roles in ecosystems, food supply, medicine, and climate

If plants don’t move, how do they respond to their environment?

By changing growth and activity based on environmental information

What does it mean that plants “harvest diffuse resources“?

They obtain resources that exist in low concentrations in the environment

What key resources do plants need from their environment?

CO₂, water, light, and nutrients like nitrogen, phosphorus, and potassium

What do plants create from simple resources like CO₂ and water?

All the complex molecules needed to build structures like trees and flowers

What is key to understanding how plants work?

Integrating information across levels of organization in the plant body

What levels of organization must be analyzed in plants?

Molecules, cells, tissues, organs, and systems

What are cells?

Membrane-bound structures that form the fundamental unit of life

What are tissues?

Group of cells that perform a common function

What are organs in plants?

Structures made of 2 or more tissues that perform a specific function

What are systems in plants?

Groups of organs that work together to perform an integrated function

What is meant by a “nested hierarchy“ in biology?

Each level of organization builds on the previous one

What are cells made of?

Many molecules

What are tissues made of?

Many cells

What are organs made of?

Several tissues

What are systems made of?

Several to many organs

What is a whole organism made of?

Several to many systems

What are three core features of the plant way of life?

1. Staying in 1 place

2. Harvesting diffuse resources

3. Manufacturing all required macromolecules

What resources do plants gather from their environment?

CO₂, sunlight, water, and mineral nutrients

What macromolecules do plants synthesize from scratch?

Nucleic acids, proteins, carbohydrates, and lipids

Are plants truly “static“ organisms?

No, they are constantly changing

How do plants respond to environmental changes?

By adjusting growth patterns and biological activities

How do plants defend themselves against pathogens and predators?

By changing the synthesis and distribution of defense compounds

What nutrients do plants actively seek?

Nitrogen, phosphorus, potassium, magnesium, iron, and zinc

How do plants complete for resources like light and nutrients?

By altering root and shoot growth

What is phenotypic plasticity?

The ability of plants to change size, shape, and activity in response to the environment

What are plant sensory systems?

Molecules and cells that detect environmental changes affecting fitness

What environmental factors can plants sense?

Light quality and amount, water status, nutrients, pathogens, predators, and day lengtj

Why are plant sensory systems important?

They allow plants to respond and adapt to changing environmental conditions

What happens to electrons when pigments absorb light in the light-dependent reactions?

They are boosted to a high-energy state and transferred to NADPH

Why must electrons be replaced in the light-dependent reactions?

To keep the system functioning continuously

Where do replacement electrons come from in photosynthesis?

From splitting water (H₂O)

Which system splits water to provide electrons?

Photosystem II (PSII)

What enzyme action occurs in Photosystem II?

It catalyzes the splitting of water molecules

What important byproduct is released when water is split?

Oxygen (O₂)

What molecule is produced by the Calvin cycle?

G3P

What are 2 main uses of G3P?

1. To produce glucose

2. To build other macromolecules

Why are carbon-containing molecules important for organisms?

They enable growth, maintenance, and reproduction

What is the overall result of photosynthesis?

The production of carbon-containing molecules that provide energy and structure for life

What building materials does G3P help produce?

Amino acids, nucleic acids, carbohydrates, and lipids

How is glucose used in cellular respiration?

It is broken down in mitochondria to produce ATP

What can glucose made from G3P be used for in plants?

1. Transport

2. Storage as starch

3. Energy production via cellular respiration

What is the basic functional distinction between primary and secondary growth?

Primary growth is responsible for acquiring light and resources in the soil; Secondary growth is responsible for structural support