Biology Chapter: Basic Units of Organization

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Questions and Answers

What is the most basic unit of organization in biological systems?

Organs

Organ Systems

Tissues

Cells (correct)

What is the role of tissues in relation to organs?

Multiple tissues work together to enable organs to perform specific functions. (correct)

Tissues conduct gas exchange directly.

Tissues act independently of organs.

Tissues only provide structural support to organs.

How do plants exchange gases, considering they lack a lung/blood system?

Using their vascular system exclusively.

Via stomata which allow gases to diffuse in and out. (correct)

By actively pumping gases through tissues.

Through roots only.

What gases move through plant cells and their surroundings by passive transport?

O2, CO2, H2O Signup and view all the answers

Which of the following accurately describes the role of specialized cells in tissues?

Similar cells cluster together to form tissues that perform a specific function. Signup and view all the answers

What is necessary for organs to perform complex functions?

Collaboration between different tissues. Signup and view all the answers

Which statement is correct regarding stomata in leaf cells?

They control the diffusion of gases in and out of the leaf. Signup and view all the answers

What is the significance of the arrangement of tissues in organs like roots and stems?

They work together to enable specific functions. Signup and view all the answers

What is the main function of leaves in a plant?

Conduct photosynthesis Signup and view all the answers

Which specialized structure in leaf cells is responsible for trapping light energy?

Chloroplasts Signup and view all the answers

What role do roots perform in a plant?

Uptake water and nutrients Signup and view all the answers

Cellular respiration in plant and animal cells mainly occurs in which cellular structure?

Mitochondria Signup and view all the answers

What is a key advantage of multicellularity in organisms?

Larger size and variety of specialized cells Signup and view all the answers

Which of the following statements about cell specialization is true?

Specialized cells work together to ensure plant survival. Signup and view all the answers

What is the overall reaction formula for photosynthesis?

6CO2 + 6H2O + light → C6H12O6 + 6O2 Signup and view all the answers

Why must the organization of cells in a leaf be so structured?

To enhance photosynthesis efficiency Signup and view all the answers

What effect does auxin have on stem cells in plants?

It stimulates their growth. Signup and view all the answers

In which direction do stems typically grow in response to gravity?

Against gravity Signup and view all the answers

How do roots utilize gravity to their advantage?

By growing towards gravity to find soil, water, and minerals Signup and view all the answers

What physiological response do touch-sensitive plants like the Venus Fly Trap utilize?

Nastic response Signup and view all the answers

What role does auxin play in the growth of roots?

It inhibits growth of cells in roots. Signup and view all the answers

What causes guard cells to swell and open stomata?

Increase in water pressure Signup and view all the answers

What is the primary function of the xylem in plants?

Transporting water from roots to leaves Signup and view all the answers

How do plants in dry, hot climates manage their stomata?

Open stomata at night and close during the day Signup and view all the answers

What happens to turgor pressure when water vapor is lost from a plant?

It decreases, causing guard cells to deflate Signup and view all the answers

What process allows water to enter root hairs?

Osmosis Signup and view all the answers

What role does phloem play in plant transport systems?

Carrying sugars from leaves to other parts of the plant Signup and view all the answers

What is xylem sap?

Fluid containing water and minerals collected in xylem Signup and view all the answers

Why do guard cells change shape?

To regulate the opening and closing of stomata Signup and view all the answers

What is the primary role of companion cells in phloem function?

They assist phloem cells to avoid clogging. Signup and view all the answers

What process causes water to move into phloem cells as sugar concentration increases?

Osmosis Signup and view all the answers

Which of the following statements about phloem sap is accurate?

It is hypertonic in comparison to surrounding cells. Signup and view all the answers

What triggers plants to exhibit phototropism?

Light as a stimulus Signup and view all the answers

How do sugars and nutrients enter the phloem?

Through active transport mechanisms. Signup and view all the answers

What is the relationship between sugar concentration in phloem cells and water movement?

Higher sugar concentration causes water to enter by osmosis. Signup and view all the answers

Which of the following best describes the movement of phloem sap?

It moves from areas of high concentration to low concentration. Signup and view all the answers

What might occur if companion cells were absent from phloem tissues?

Phloem cells would become clogged with organelles. Signup and view all the answers

What is the primary function of lenticels in plants?

Gas exchange Signup and view all the answers

During cellular respiration, what gases are consumed and produced by plants?

O2 consumed, CO2 and H2O produced Signup and view all the answers

Which structures in leaves are primarily responsible for gas exchange?

Stomata Signup and view all the answers

What is the relationship between stomata opening and transpiration?

Open stomata increase transpiration rates Signup and view all the answers

How do guard cells control the opening and closing of stomata?

By adjusting their turgor pressure with water Signup and view all the answers

What happens when water is lost from guard cells?

They shrink and cause stomata to close Signup and view all the answers

What is the primary gas used by plants during photosynthesis?

Carbon dioxide Signup and view all the answers

What is transpiration in plants?

Evaporation of water from stomata Signup and view all the answers

Study Notes

Do Now Problems

Draw the Lewis structure for carbon tetrafluoride (CF₄). The structure shows a central carbon atom bonded to four fluorine atoms. Each fluorine atom has a single bond to the carbon, and there are lone pairs of electrons around each fluorine atom.
What are the three parts of the modern cell theory? Cells are the basic unit of life, all living things are made of cells, and all cells arise from pre-existing cells.

Topic 3a - Specialized and Organized

Cells make up all life on Earth. Plants are a group of multicellular organisms that are the basis of the energy requirements for all other organisms on Earth.

Cellular Organization

All multicellular organisms are composed of multiple specialized cells, each designed for specific functions.
Cells similar in structure and function are grouped together to form tissues.
Tissues working together form organs.
Organs work together to complete a specific function in an organ system.
Several organ systems working together make up an organism

Plant Organs

Plants have organs like leaves, stems, and roots.
Plant cells take in water and minerals, produce glucose, transport water, etc. Not all plant cells perform all functions. Specialized cells perform specific tasks. All these specialized cells/organs work together for the whole plant to survive.
Leaves - main function is photosynthesis (producing food).
Stems - transport water and nutrients throughout the plant.
Roots - take up water and nutrients from the soil.

Cell Specialization in Leaves

Leaf cells contain specialized cells that perform photosynthesis in chloroplasts.
Chlorophyll traps light energy from the sun that is used in a reaction with water and carbon dioxide.
This reaction produces glucose (energy source for plants and animals) and oxygen.

Cellular Respiration

Cellular respiration is the opposite of photosynthesis. It is a reaction that occurs in plant and animal cells that uses mitochondria to convert glucose into usable energy (ATP).
Leaf cells have different structures and arrangements determined by their specific tasks (functions).

Worksheet - Function/Structure of Leaf Cells

The Epidermal cell protects.
Palisade Tissue - absorbs light and performs photosynthesis.
Spongy Tissue - gas exchange.
Stomata - gas exchange.
Vascular - transports water and nutrients.

Cell Tissue, Organ, System

Advantages of multicellular organisms: large size, variety of specialized cells, and ability to thrive in different environments.
However, cells must be very organized.

Gas Exchange in Plants

Plants need to exchange gases (CO2, O2, H2O).
Stomata are pores on leaves that allow gas exchange; they are controlled by guard cells.
Lenticels are pores on stems that allow gas exchange.
Stomata and lenticels may open or close to regulate gas exchange.
The exchange of gases is coupled with water, and this process is called transpiration.

Water Transport in Plant

Water transported via osmosis in individual cells.
Water transported over longer distances throughout the whole plant.
Xylem transports water from the roots to the leaves, phloem transports sugar from the leaves to the rest of the plants.

Sugar Transport in Phloem

Sugars produced in leaves are transported to other parts of the plant via the phloem.
Transport occurs through osmosis.
Companion cells are important for phloem function because they assist the phloem cells in doing their tasks (like transporting nutrients).

Plant Control Systems

Multicellular organisms respond to environmental factors.
Plants, like other organisms, respond to environmental changes (tropisms). These responses are often more subtle.

Phototropism

Light is an important stimulus for plants.
Plants grow towards a light source (phototropism) to maximize photosynthesis.

Gravitropism

Plants respond to gravity (gravitropism).
Stems grow upwards, roots grow downwards.
Auxin affects cell growth rates, causing curves in stems and roots.

Nastic Response

Some plants respond quickly to touch (nastic response).
Examples include Venus flytrap and Mimosa.

Studying That Suits You

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Description

Test your understanding of the fundamental concepts in biological organization, including the roles of cells, tissues, and organs. This quiz covers essential topics such as gas exchange in plants, the function of specialized cells, and the significance of cellular structures. Challenge yourself to grasp how multicellularity enhances biological functions.