L2 Unit 1 AOS2 Bio: Plant and Animal Cell Specialisation

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Questions and Answers

What do cells need to function?

energy (ATP), nutrients, remove waste/toxin, stable internal conditions

What are the components of vascular tissue in plants?

Xylem tissue (correct)

Ground tissue

Phloem tissue (correct)

Dermal tissue

Xylem tissue transports water and minerals in one direction from leaves to roots.

False

Connective tissues provide structural support for organs in the body, while ___ tissue contracts to exert a force.

muscle Signup and view all the answers

Match the following animal tissue types with their functions:

Muscle tissue = Contracts to exert a force Nervous tissue = Detects stimuli and transmits electrical signals Connective tissue = Connects and supports other tissues and organs Epithelial tissue = Protects from injury and disease, lines organs and vessels Signup and view all the answers

What is the role of the root system in plants?

Provide stability and support, absorb water and nutrients Signup and view all the answers

Does diffusion occur faster when the SA:V ratio is high or low?

Higher Signup and view all the answers

What are the two types of cells that make up the xylem?

Vessel elements and tracheids Signup and view all the answers

Lignified cells in the xylem are strengthened by woody lignin deposits.

True Signup and view all the answers

____ cells and companion cells are located next to each other and regulate the entry of nutrients into the phloem.

Sieve Signup and view all the answers

What is translocation also known as?

Source and sink movement Signup and view all the answers

What is turgor?

Pressure of the cell wall Signup and view all the answers

What is the primary function of xylem in plants?

Transport of water and minerals Signup and view all the answers

Which of the following is NOT a product of photosynthesis?

Water Signup and view all the answers

Transpiration in plants primarily occurs through which structure?

Leaves Signup and view all the answers

What is the role of stomata in plant leaves?

Exchange of gases Signup and view all the answers

Explain the process of water transport from the roots to the leaves in a plant.

Water is absorbed by the roots and travels up the plant through the xylem vessels due to capillary action and transpiration. This process is crucial for delivering water and nutrients to the leaves for photosynthesis. Signup and view all the answers

Discuss the role of the guard cells in the functioning of the stomata.

Guard cells regulate the opening and closing of stomata. When they swell with water and become turgid, the stomata open for gas exchange and transpiration. When they lose water and become flaccid, the stomata close to prevent water loss. Signup and view all the answers

Define the term 'turgor pressure' and its importance in plants.

Turgor pressure is the pressure exerted by the fluid content of plant cells against the cell wall. It helps maintain cell rigidity, necessary for plant support and structural integrity. Turgor pressure also plays a role in the opening and closing of stomata. Signup and view all the answers

Study Notes

Cells to Systems

Multicellular life requires cells to function together, providing energy, nutrients, oxygen, and removing waste to maintain equilibrium and stable internal conditions.
Cells can become specialized to perform specific individual functions, and as they increase in size and complexity, greater cooperation and coordination are required to survive.

Organisation of Plants

Vascular plants require vascular tissue to transport water and nutrients throughout the plant.
Plant tissues include:
- Dermal tissue: a single layer of cells that covers the outside of a plant, secreting a film to form a physical barrier, reducing water loss and physical damage.
- Ground tissue: makes up the majority of the interior of the plant, carrying out metabolic functions, and vascular tissues run through it, carrying water and nutrients.
Plant organs include:
- Reproductive organs: flowers, fruits, and seeds.
- Non-reproductive organs: leaves, stems, and roots.
Plant systems include:
- Root system: located underground, absorbs water and nutrients from the soil, providing support and structure.
- Shoot system: includes reproductive organs, stems, and leaves, responsible for photosynthesis and growth.

Organisation of Animals

Animal cells combine to form four major tissue types:
- Muscle tissue: enables movement by generating force.
- Nervous tissue: detects stimuli and transmits electrical signals.
- Connective tissue: provides structural support and connects organs.
- Epithelial tissue: forms barriers, provides protection, and assists in secretion and absorption.
Animal organs include:
- Tissues + cells that perform a specific function.
- Examples: heart, lungs, liver, kidneys, etc.
Animal systems include:
- Circulatory system: pumps blood throughout the body, providing oxygen and nutrients.
- Respiratory system: brings oxygen into the body and removes carbon dioxide.
- Nervous system: controls and coordinates body functions.
- Digestive system: breaks down and absorbs nutrients.

Plant Vascular Tissues

Vascular tissues transport water and nutrients throughout the plant.
Includes xylem and phloem tissue.
- Xylem tissue: transports water and minerals from the roots to the leaves in one direction.
- Phloem tissue: transports sugars and other nutrients around the plant in both directions.

Mechanisms of Water and Nutrient Movement in Vascular Plants

Water and essential nutrients are absorbed from the soil by the roots.
Water and nutrients travel up the xylem to the leaves.
Photosynthesis occurs, requiring water to produce glucose.
Glucose and other nutrients are transported throughout the rest of the plant in the phloem.

Root System

Functions:
- Provide stability and support to a plant.
- Absorb water and minerals from the soil.
Root cells:
- Absorb water and nutrients from the soil.
- Root hair cells are finger-like projections that increase the surface area of the roots.

Pathways of Water and Nutrient Absorption into Roots

Extracellular pathway: water and dissolved solutes diffuse into the roots through the apoplastic route.
Cytoplasmic pathway: minerals passively diffuse into the cytoplasm or are taken up via active transport in root hair cells.

Structure and Function of the Xylem

Long, skinny tubes that run throughout the plant, made up of vessel elements and tracheids.
Vessel elements are larger and stack end-to-end, forming a tube that lets water flow vertically through the xylem.
Tracheids are smaller and have tapered ends, allowing water to flow horizontally through pits before continuing vertically.

Similarities and Differences between Vessel Elements and Tracheids

Both are hollow cells that strengthen the cell wall with lignin deposits.
Vessel elements are larger and stack end-to-end, while tracheids are smaller and have overlapping endings.

Sieve Cells and Companion Cells

Regulate the entry of nutrients into the phloem.
Companion cells are located next to sieve cells and help regulate the entry of nutrients.

Movement in the Xylem

Transpiration: the evaporation of water from leaves and the movement of liquids up the xylem.
Water evaporates from the leaf and exits through the stomata, creating a force that draws water up from the xylem to the leaf.
Capillary action helps water flow into the xylem.

Transpiration

Important for regulating heat and water balance, distributing nutrients, and preventing wilting.
Characteristics:
- Water evaporates from the leaf and exits through the stomata.
- Air pressure in the leaf becomes lower than the pressure in the roots.
- A force that draws water up from the xylem to the leaf is generated.### Adhesion and Cohesion
Adhesion is the attraction between a liquid and a surface, causing the liquid to flow in narrow tubes.
Examples of adhesion: water flowing in narrow tubes, sticking of bandaids to the skin.

Translocation

Translocation is the movement of substances from a source to other tissues in the plant via the phloem.
Sources: tissues or plants where substances are produced or enter the plant.
Sinks: tissues of a plant where substances are stored.
Glucose is the main nutrient of plants.

Steps of Translocation

Glucose is produced in the leaf cell and pumped into the companion cells.
Glucose diffuses into the sieve cells of the phloem, increasing the concentration of glucose.
Water diffuses into the sieve cells from the xylem, increasing turgor pressure.
The liquid in the phloem gets pushed throughout the plant, and glucose is actively transported into required cells (sinks).
Glucose is unloaded into sink cells, decreasing the concentration of glucose in the phloem.

Turgor Pressure

Turgor pressure is the internal pressure of a plant cell against its cell wall.
High turgor pressure makes the cell stiff and rigid.
Low turgor pressure makes the cell flimsy and less supportive.

Factors Affecting Transpiration Rates

Temperature: high temperatures increase transpiration rates.
Light: necessary for photosynthesis and allows for gas exchange.
Humidity: low humidity increases transpiration rates.
Water availability: affects transpiration rates.

Guard Cells

Guard cells are a pair of curved cells that surround a stoma.
When stomata are closed, gases cannot freely exchange in the leaf, reducing photosynthesis, transpiration, and water loss.
Increasing transpiration rates: pump K+ ions into guard cells, increasing solute concentration, and water diffuses into guard cells via osmosis.
Decreasing transpiration rates: pump K+ ions out of guard cells, and water diffuses out of guard cells, making them flaccid.

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Description

This quiz covers the organisation of plants and animals, including cell specialisation, vascular tissues, and the requirements for cells to function.