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Questions and Answers
Which of the following best describes the function of red blood cells?
Which of the following best describes the function of red blood cells?
The heart is made up of only one type of tissue.
The heart is made up of only one type of tissue.
False
What is the primary function of the leaf in a plant?
What is the primary function of the leaf in a plant?
To produce sugar and oxygen via photosynthesis.
The _____ system in animals is responsible for transporting substances and heat.
The _____ system in animals is responsible for transporting substances and heat.
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Match the following plant structures with their functions:
Match the following plant structures with their functions:
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Which type of cells have thin walls and needle-like extensions for absorption?
Which type of cells have thin walls and needle-like extensions for absorption?
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Muscle tissue in animals is responsible for movement.
Muscle tissue in animals is responsible for movement.
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What are the three types of tissues in plants?
What are the three types of tissues in plants?
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Which of the following best describes the primary difference between unicellular and multicellular organisms?
Which of the following best describes the primary difference between unicellular and multicellular organisms?
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All cells in a multicellular organism are genetically different from one another.
All cells in a multicellular organism are genetically different from one another.
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What is the role of regulatory proteins in gene expression?
What is the role of regulatory proteins in gene expression?
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The ________ shape of red blood cells increases their surface area for oxygen absorption.
The ________ shape of red blood cells increases their surface area for oxygen absorption.
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Match the following specialized cells with their function:
Match the following specialized cells with their function:
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What percentage of genes does an average human cell express at any given time?
What percentage of genes does an average human cell express at any given time?
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Gene expression can vary based on cell type, developmental stage, and time.
Gene expression can vary based on cell type, developmental stage, and time.
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What is cell differentiation?
What is cell differentiation?
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Which organ system relies on the respiratory system for oxygen supply?
Which organ system relies on the respiratory system for oxygen supply?
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Smoking has a positive effect on lung tissue health.
Smoking has a positive effect on lung tissue health.
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What is the primary function of the palisade mesophyll in leaves?
What is the primary function of the palisade mesophyll in leaves?
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Excessive alcohol consumption increases the risk of _____ disease.
Excessive alcohol consumption increases the risk of _____ disease.
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Match the following materials with their corresponding exchange types.
Match the following materials with their corresponding exchange types.
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What characteristic increases the efficiency of exchange surfaces in multicellular organisms?
What characteristic increases the efficiency of exchange surfaces in multicellular organisms?
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Unicellular organisms need specialized structures for material exchange.
Unicellular organisms need specialized structures for material exchange.
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Name one harmful lifestyle choice that can affect organ system function.
Name one harmful lifestyle choice that can affect organ system function.
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The _____ tissue in leaves transports water.
The _____ tissue in leaves transports water.
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Study Notes
Unicellular vs. Multicellular Organisms
- Unicellular organisms are composed of a single cell (e.g., bacteria, yeast).
- Multicellular organisms are made up of many cells (e.g., animals, plants, fungi).
DNA, Chromosomes, and Genes
- DNA is a molecule that carries genetic information.
- Genes are sections of DNA that encode instructions for specific proteins.
- Chromatin is loose DNA strands in the nucleus.
- Chromosomes are tightly packed DNA, each containing hundreds of genes.
- Chromosomes are pairs found in cells, with humans having 46 chromosomes or 23 pairs.
- All cells within a multicellular organism have the same number and type of chromosomes and the same genetic sequence.
Gene Expression
- Gene expression is when a gene is "switched on" and its instructions are used to produce a specific protein.
- Gene expression is controlled by regulatory proteins.
- Activators bind near genes to "switch" them on.
- Repressors bind near genes to "switch" them off.
- Gene expression varies according to cell type and time (e.g., after eating, puberty).
- On average, a human cell expresses approximately 20% of its genes at any one time.
Cell Specialization
- Cell specialization is the development of different cell types with unique characteristics and functions in multicellular organisms.
- This occurs through cell differentiation, focusing on specific genes to create a specific set of proteins for each cell type.
- Examples include red blood cells (biconcave shape, no nucleus, high surface area for maximized oxygen transport), leaf cells (large surface area, thin walls, chloroplasts for photosynthesis and nutrient absorption).
Hierarchical Organization
- Cells, Tissues, Organs, Systems, Organism: Multicellular organisms are categorized hierarchically.
Tissue
- Tissues are groups of similar cells with a shared function.
- Examples: muscle tissue (muscle cells).
Organs Example
- Organs are composed of different tissues that work together (examples: heart, stomach, leaf, root).
- Hearts use cardiac muscle, epithelium, and blood tissues to pump blood.
- Stomachs use specialized tissue for digestion and kill bacteria.
- Leaves/roots facilitate specific functions.
Systems
- Systems are groups of organs working together to perform specific functions (Examples: circulatory system, shoot system).
- The circulatory system involves the heart, blood vessels, and transports substances, as well as regulating temperature.
- The shoot system in plants transports substances and facilitates plant support and reproduction.
Relationship Between Structure and Function
- Cell structure determines cell function (e.g., sperm cells with tails for movement).
Gas Exchange in Organisms
- Unicellular organisms exchange materials directly with their environment (e.g., through their cell membranes).
- Multicellular organisms use specialized exchange surfaces (e.g., alveoli).
- These surfaces are thin, moist, and have large surface areas to improve gas exchange.
- They are located near blood vessels/capillaries to enhance exchange efficiency.
- Examples of animal exchange specialized surfaces include alveoli (lungs), villi (small intestine), and nephrons (kidneys).
Gas Exchange in Plants
- Plants exchange gases (CO2 and O2) mostly through stomata, openings located mostly on the lower epidermis of leaves.
- CO2 enters
- O2 exits
- Guard cells control stomata opening and closing, regulating transpiration and reducing water loss.
- Plants use various structures like stomata, lenticels, and roots to transfer gases.
Leaf Structure
- Leaves are part of the shoot system in plants.
- Parts of leaves include the upper and lower epidermis, and mesophyll.
- Palisade mesophyll is densely packed with chloroplasts for photosynthesis.
- Spongy mesophyll is loosely packed for gas diffusion/exchange.
- Stomata are openings (mostly on the underside) that allow for gas exchange.
- Vascular tissues (xylem and phloem) transport water and sugars.
Adaptations for Water Loss Avoidance in Leaves
- Stomata are mostly on the underside and low stomatal density reduces water loss.
- Waxy cuticle on the upper epidermis can also aid in reducing water loss.
Obtaining Nutrients in Animals
- Animals consume nutrients to fuel their bodies' function.
- Digestive systems mechanically and chemically break down food using teeth, chemical enzymes (amylase, protease, lipase), and stomach churning for easier absorption.
- Nutrient types for digestion and absorption include protein, carbohydrates, and lipids; resulting in amino acids, sugars and fatty acids/glycerol.
Obtaining Nutrients in Plants
- Green plants/autotrophs can make their own food (nutrients) through photosynthesis.
Respiration
- Respiration is part of every organism's function.
- It facilitates gas exchange (between the internal blood and atmospheric environment within the organism) to ensure organisms obtain necessary energy (energy in the form of ATP).
Excretory Systems (Waste Removal)
- Excretory systems in animals remove metabolic wastes (e.g., urea).
- Specialized structures such as the kidneys filter blood and excrete urine.
- In plants, carbon dioxide is removed via stomata, lenticels and root hairs.
- Wastes in plants are stored in vacuoles or other parts of the plant that are shed eventually.
- Guttation discharges water and waste containing solutes at night mostly via hydathodes.
Effect of Alcohol on Urine Output
- Alcohol inhibits the release of ADH (antidiuretic hormone), resulting in reduced water reabsorption in the kidneys and increased urine output. This can lead to dehydration.
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Description
Explore the fascinating differences between unicellular and multicellular organisms, and delve into the structure and function of DNA, chromosomes, and genes. Learn how gene expression is regulated and the intricacies of genetic information in living organisms.
