Biology Chapter 5: Life Processes

Questions and Answers

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

Because simple diffusion cannot facilitate enough oxygen delivery to all cells in a larger body.

What criteria do we use to decide whether something is alive?

The ability to grow, reproduce, respond to stimuli, and maintain homeostasis.

What are outside raw materials used for by an organism?

They are used for energy, growth, and the synthesis of essential substances.

What processes would you consider essential for maintaining life?

Nutrition, respiration, circulation, and excretion. Signup and view all the answers

Which of these organisms are considered autotrophs?

Bacteria Signup and view all the answers

What is photosynthesis?

The process by which autotrophs convert carbon dioxide and water into carbohydrates using sunlight. Signup and view all the answers

What role do enzymes play in heterotrophic nutrition?

Enzymes help break down complex food substances into simpler ones. Signup and view all the answers

All organisms obtain their food in the same way.

False Signup and view all the answers

What happens to carbohydrates not used immediately by plants?

They are stored in the form of starch. Signup and view all the answers

What are the differences between autotrophic nutrition and heterotrophic nutrition?

Autotrophic nutrition involves organisms producing their own food from inorganic substances, while heterotrophic nutrition involves organism consuming organic substances for food. Signup and view all the answers

Where do plants get each of the raw materials required for photosynthesis?

Plants obtain carbon dioxide from the air, water from the soil, and sunlight from the sun. Signup and view all the answers

What is the role of the acid in our stomach?

The acid in the stomach helps create an acidic medium that facilitates the action of the enzyme pepsin, which digests proteins. Signup and view all the answers

What is the function of digestive enzymes?

Digestive enzymes break down complex food molecules into smaller, absorbable molecules such as amino acids, glucose, and fatty acids. Signup and view all the answers

How is the small intestine designed to absorb digested food?

The small intestine has a large surface area due to villi and microvilli, which increases absorption efficiency. Signup and view all the answers

What does a color change in the starch solution indicate?

A color change indicates the presence of a breakdown product of starch, suggesting that salivary amylase has acted on it. Signup and view all the answers

What does blowing air through lime water tell us about the amount of carbon dioxide in the air we breathe out?

Blowing air through lime water makes it turn milky, indicating the presence of carbon dioxide. Signup and view all the answers

What change is observed in the lime water during fermentation?

The lime water turns milky, indicating the production of carbon dioxide due to fermentation. Signup and view all the answers

What are the two types of respiration in organisms?

Aerobic respiration, which uses oxygen, and anaerobic respiration, which does not use oxygen. Signup and view all the answers

What does the accumulation of lactic acid in muscles during sudden activity cause?

The accumulation of lactic acid causes muscle cramps. Signup and view all the answers

What helps in removing germs and dust from the respiratory tract?

The cilia in the respiratory tract help to remove germs, dust, and other harmful particles. Signup and view all the answers

What advantage does a terrestrial organism have over an aquatic organism with regard to obtaining oxygen for respiration?

Terrestrial organisms can obtain oxygen more efficiently from the air due to the presence of respiratory pigments like haemoglobin. Signup and view all the answers

What are the different ways in which glucose is oxidised to provide energy in various organisms?

Glucose can be oxidised aerobically in the presence of oxygen or anaerobically in the absence of oxygen, producing different end products. Signup and view all the answers

How is oxygen and carbon dioxide transported in human beings?

Oxygen is mainly transported by haemoglobin in red blood cells, while carbon dioxide is primarily dissolved in blood plasma. Signup and view all the answers

How are the lungs designed in human beings to maximise the area for exchange of gases?

The lungs contain alveoli, which increase the surface area for gas exchange significantly. Signup and view all the answers

What are the components of the transport system in human beings?

The components include the heart, blood vessels (arteries, veins, capillaries), and blood. Signup and view all the answers

What are the functions of these components?

The heart pumps blood, arteries carry blood away from the heart, veins return blood to the heart, and capillaries are sites for exchange of materials. Signup and view all the answers

Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?

Separating oxygenated and deoxygenated blood allows for a more efficient oxygen supply to the body, especially in high-energy animals. Signup and view all the answers

What are the components of the transport system in highly organised plants?

The components include xylem and phloem for transporting water, minerals, and nutrients. Signup and view all the answers

How are water and minerals transported in plants?

Water and minerals are transported through xylem vessels using capillary action and root pressure. Signup and view all the answers

How is food transported in plants?

Food is transported through phloem via translocation, utilizing energy to move soluble products. Signup and view all the answers

High blood pressure is also called hypertension.

True Signup and view all the answers

What is the role of platelets in the blood?

Platelets help in clotting blood to prevent excessive bleeding. Signup and view all the answers

What is transpiration in plants?

Transpiration is the loss of water vapor from plant leaves, aiding in the absorption of water and nutrients. Signup and view all the answers

What is the normal range of haemoglobin content in human beings?

The normal range is typically about 12-16 g/dL for women and 14-18 g/dL for men. Signup and view all the answers

Describe the structure and functioning of nephrons.

Nephrons consist of a cluster of thin-walled blood capillaries (glomerulus) and a cup-shaped structure (Bowman's capsule) that collects filtrate. They filter waste from the blood, reabsorbing glucose, amino acids, and water, producing urine. Signup and view all the answers

What are the methods used by plants to get rid of excretory products?

Plants use transpiration to eliminate excess water, store waste in vacuoles or as resins and gums, and can lose parts like leaves to expel wastes. Signup and view all the answers

How is the amount of urine produced regulated?

The amount of urine produced is regulated by the kidneys, which selectively reabsorb water depending on the body's hydration levels and the concentration of dissolved wastes. Signup and view all the answers

The kidneys in human beings are a part of the system for:

Excretion Signup and view all the answers

The xylem in plants are responsible for:

Transport of water Signup and view all the answers

The autotrophic mode of nutrition requires:

All of the above Signup and view all the answers

The breakdown of pyruvate to give carbon dioxide, water and energy takes place in:

Mitochondria Signup and view all the answers

How are fats digested in our bodies? Where does this process take place?

Fats are digested by bile and pancreatic lipase in the small intestine. Signup and view all the answers

What is the role of saliva in the digestion of food?

Saliva moistens food, contains enzymes like amylase that begin the breakdown of carbohydrates. Signup and view all the answers

What are the necessary conditions for autotrophic nutrition and what are its by-products?

Autotrophic nutrition requires sunlight, carbon dioxide, and water; by-products include oxygen and glucose. Signup and view all the answers

What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.

Aerobic respiration uses oxygen and produces more energy; anaerobic does not use oxygen and produces less energy. Organisms like yeast and certain bacteria use anaerobic respiration. Signup and view all the answers

How are the alveoli designed to maximize the exchange of gases?

Alveoli have a large surface area, thin walls, and a moist lining that facilitate efficient gas exchange. Signup and view all the answers

What would be the consequences of a deficiency of hemoglobin in our bodies?

Deficiency of hemoglobin leads to reduced oxygen transport, resulting in fatigue, weakness, or anemia. Signup and view all the answers

Describe double circulation of blood in human beings. Why is it necessary?

Double circulation involves two circuits: one for oxygenation via lungs and one for systemic circulation. It allows efficient oxygen transport and waste removal. Signup and view all the answers

What are the differences between the transport of materials in xylem and phloem?

Xylem transports water and minerals unidirectionally from roots to stems/leaves, while phloem transports nutrients (sugars) bidirectionally throughout the plant. Signup and view all the answers

Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

Both have large surfaces (alveolar sacs and nephron tubules) for efficient exchange: alveoli facilitate gas exchange; nephrons filter blood to produce urine. Signup and view all the answers

Study Notes

Life Processes Overview

Differentiating between living and non-living entities involves observing movement, growth, and breathing.
Both visible and invisible movements (e.g., molecular movement) are crucial indicators of life.
Viruses demonstrate the complexity of defining life as they lack molecular movement until infecting a host.

Essential Life Processes

Life processes refer to the maintenance functions necessary for survival, which occur continuously, even during inactivity.
Energy for these processes must come from external sources, primarily in the form of food.
Organisms require raw materials for growth, mainly derived from carbon-based sources.

Nutritional Processes

Autotrophs (e.g., green plants, some bacteria) synthesize their nutrients using inorganic sources and light through photosynthesis.
Heterotrophs (e.g., animals, fungi) rely on breaking down complex organic substances for nutrition.
Photosynthesis involves stages: light absorption, water splitting, and carbon dioxide reduction to carbohydrates.

Autotrophic Nutrition Details

Photosynthesis converts carbon dioxide and water into carbohydrates, storing excess as starch.
Stomata on leaves facilitate gas exchange; guard cells control their opening and closing to manage water loss.
Nutrients like nitrogen are absorbed from the soil, necessary for protein synthesis in plants.

Heterotrophic Nutrition Strategies

Fungi break down food externally before absorption, while other organisms consume whole food for digestion.
Parasitic relationships allow organisms to derive nutrition from hosts without killing them (e.g., leeches, lice).
The complexity of the organism's structure influences its digestive system's design.

Digestion in Humans

The alimentary canal, a tubular structure from mouth to anus, has specialized regions for specific digestive processes.
Saliva contains enzymes like amylase that initiate starch breakdown during mastication.
Peristalsis, a series of rhythmic contractions, moves food through the digestive tract, ensuring proper processing.

Photosynthesis Experimentation

Variegated leaves demonstrate chlorophyll's necessity for starch production during photosynthesis.
Experimental setups with potassium hydroxide absorb carbon dioxide, validating its role in the photosynthetic process.
Materials like nitrogen and minerals are vital for plant growth, obtained through water absorption by roots.

Summary of Key Functions

Organisms maintain order through energy intake, nutrient processing, and waste removal.
Gas exchange and nutrient transportation in multicellular organisms necessitate specialized tissues and systems.
Understanding these processes highlights the reliance of life on both energy and raw materials from the environment.### Digestion and Absorption
Gastric glands in the stomach wall secrete hydrochloric acid, pepsin (a protein-digesting enzyme), and mucus.
Hydrochloric acid provides an acidic environment for pepsin, aids in protein digestion, and protects against pathogens.
Mucus safeguards the stomach lining from acidic damage.
Sphincter muscles regulate food exit from the stomach into the small intestine.

Structure of the Small Intestine

The small intestine is the longest part of the alimentary canal, coiled for compactness.
Length varies among animals; herbivores have longer intestines for cellulose digestion, while carnivores have shorter ones.
It is the main site for carbohydrate, protein, and fat digestion, aided by enzymes from the pancreas and bile from the liver.

Role of Bile and Pancreatic Enzymes

Bile neutralizes stomach acid, making the intestinal environment alkaline for pancreatic enzyme action.
Bile salts emulsify fats, breaking them into smaller globules for more effective digestion.
Pancreatic juice contains enzymes like trypsin (for proteins) and lipase (for emulsified fats).

Final Digestion and Absorption

Intestinal glands secrete intestinal juice, converting proteins to amino acids, complex carbohydrates to glucose, and fats to fatty acids and glycerol.
Villi, finger-like projections in the small intestine, increase surface area for absorption and are rich in blood vessels for nutrient transport.

Large Intestine Function

Unabsorbed food moves to the large intestine, where water is further absorbed.
Waste is expelled through the anus, regulated by the anal sphincter.

Dental Caries

Dental caries is caused by bacteria producing acids from sugars, leading to enamel demineralization.
Dental plaque forms and covers teeth, hindering saliva's action against acid.
Regular brushing prevents plaque buildup and tooth decay.

Respiration Types

Respiration involves breaking down glucose into energy via two pathways: aerobic (with oxygen) and anaerobic (without oxygen).
Aerobic respiration occurs in mitochondria, producing carbon dioxide and water, while anaerobic respiration in yeast produces ethanol and carbon dioxide.
In humans, lack of oxygen during exertion can lead to lactic acid buildup, causing cramps.

Energy Production and ATP

Cellular respiration releases energy used to form ATP, essential for various cellular activities.
ATP serves as the energy currency, powering muscle contractions, protein synthesis, and other vital processes.

Gas Exchange in Plants and Animals

Plants exchange gases through stomata; oxygen is utilized during photosynthesis, and CO2 is eliminated at night.
Terrestrial animals breathe oxygen from the atmosphere, while aquatic organisms extract dissolved oxygen from water.

Human Respiratory System

Air enters the body through nostrils, filtered by hair and mucus, then travels to the lungs.
Within the lungs, bronchi divide into smaller tubes ending in alveoli, where gas exchange occurs.
Haemoglobin in red blood cells carries oxygen, while carbon dioxide is primarily transported in dissolved form.

Health and Lifestyle

Smoking is detrimental to health, leading to respiratory issues, lung cancer, and other conditions.
Awareness of tobacco's harmful effects, including organ-specific cancers, emphasizes the importance of avoiding tobacco.### Human Circulatory System
The heart has separate chambers to prevent mixing of oxygenated and deoxygenated blood, ensuring efficient oxygen transport.
Oxygen-rich blood flows from the lungs to the left atrium, then to the left ventricle, which pumps it to the body.
Deoxygenated blood returns from the body to the right atrium, flows into the right ventricle, and is pumped to the lungs for oxygenation.
Ventricles have thicker muscular walls than atria due to their function of pumping blood to various organs.
Valves in the heart prevent backflow of blood during contractions.
Birds and mammals maintain a separation of blood to meet high energy demands; amphibians and reptiles have mixed blood due to having three-chambered hearts.
Fish possess a two-chambered heart, resulting in blood passing through the heart only once during circulation.

Blood Pressure

Blood pressure is defined as the force exerted by blood against vessel walls and is higher in arteries than in veins.
Systolic pressure (120 mm Hg) occurs during ventricular contraction, while diastolic pressure (80 mm Hg) happens during relaxation.
High blood pressure (hypertension) can lead to severe health issues, including artery rupture and internal bleeding.

Blood Vessels

Arteries carry blood away from the heart, featuring thick and elastic walls due to high pressure.
Veins return blood to the heart, possessing valves to ensure unidirectional flow.
Capillaries, the smallest blood vessels, facilitate the exchange of materials between blood and surrounding cells, with walls one cell thick.

Platelet Function and Lymph

Platelets prevent excessive blood loss by forming clots at injury sites, maintaining blood system integrity.
Lymph, similar to blood plasma but with less protein, is formed from tissue fluid and carries nutrients, excess fluid, and waste products back to veins.

Plant Transport System

Plants absorb nutrients and minerals from soil through roots, essential for building their structure and energy acquisition.
Specialized transport systems are vital for distributing water and nutrients across large distances in tall plants.
Xylem transports water and minerals from roots, while phloem distributes products of photosynthesis throughout the plant.

Xylem Function

Water enters roots via osmosis due to ion concentration gradients, creating a continuous water column in xylem.
Transpiration creates suction that pulls water from roots, facilitating upward movement to leaves and aiding in temperature regulation.

Phloem Function

Translocation in phloem moves photosynthetic products, amino acids, and other substances using energy (ATP).
This process allows the distribution of nutrients according to the plant’s needs, like transporting stored sugars to growing buds in spring.

Excretory System in Humans

The excretory system consists of kidneys, ureters, a urinary bladder, and a urethra.
Kidneys filter waste from blood, producing urine which is stored in the bladder until excretion.
Nephrons, the functional units of kidneys, reabsorb essential substances like glucose and water, producing concentrated urine.

Artificial Kidney

In cases of kidney failure, artificial kidneys perform dialysis to remove waste from the blood without reabsorption.
The process involves circulating blood through tubes with a semi-permeable lining in a tank of dialysing fluid, purifying the blood prior to returning it to the patient.

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Description

Explore Chapter 5 on Life Processes in Biology. This chapter delves into the characteristics that distinguish living beings from non-living entities, discussing the signs of life observable in animals and plants. Test your understanding of what constitutes life and the processes involved.