Life Processes Chapter 5

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Questions and Answers

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

Diffusion is insufficient because all cells may not be in direct contact with the surrounding environment in multi-cellular organisms.

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

We tend to think of movement, either growth-related or not, as common evidence for being alive.

What are outside raw materials used for by an organism?

Outside raw materials are used by organisms for energy, growth, repair, and maintenance of structures.

What processes would you consider essential for maintaining life?

Essential processes for maintaining life include nutrition, respiration, excretion, and transportation of nutrients. Signup and view all the answers

What are stomata and what is their function in plants?

Stomata are tiny pores present on the surface of leaves. They facilitate gaseous exchange for the purpose of photosynthesis. Signup and view all the answers

What causes the closing of stomatal pores in plants?

Guard cells shrinking Signup and view all the answers

Nitrogen is an essential element used in the synthesis of fats in plants.

False Signup and view all the answers

Amoeba takes in food using temporary finger-like extensions of the cell surface called _______.

pseudopodia Signup and view all the answers

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

Terrestrial organisms can obtain oxygen from the air in lungs more efficiently than aquatic organisms. Signup and view all the answers

How is oxygen and carbon dioxide transported in human beings?

Oxygen is carried by red blood corpuscles and carbon dioxide is transported in dissolved form in blood. Signup and view all the answers

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

The lungs have alveoli which provide a large surface area for gas exchange. Signup and view all the answers

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

Glucose can be oxidized through processes like aerobic respiration, anaerobic respiration, or fermentation. Signup and view all the answers

What causes dental caries or tooth decay?

Bacteria acting on sugars produce acids that softens or demineralises the enamel. Signup and view all the answers

What happens if untreated dental caries allows microorganisms to invade the pulp?

Inflammation and infection may be caused. Signup and view all the answers

Where does fermentation take place in yeast?

Cytoplasm Signup and view all the answers

Anaerobic respiration occurs in the presence of oxygen.

False Signup and view all the answers

In the absence of oxygen, pyruvate is converted into ________ and carbon dioxide during fermentation.

ethanol Signup and view all the answers

Describe the structure and functioning of nephrons.

Nephrons are the structural and functional units of the kidney responsible for filtering blood and producing urine. Each nephron consists of a glomerulus, Bowman's capsule, renal tubules, and collecting ducts. The glomerulus filters blood, leading to the formation of ultrafiltrate, which is further processed in the tubules to reabsorb essential substances and excrete waste products, resulting in the formation of urine. Signup and view all the answers

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

Plants eliminate excretory products through various methods such as transpiration to remove excess water, shedding leaves that store waste, storing waste in cellular vacuoles, releasing waste as resins and gums, and excreting waste substances into the soil surrounding them. Signup and view all the answers

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

The components include the heart, blood vessels, and blood. Signup and view all the answers

How is the amount of urine produced regulated?

The amount of urine produced is regulated by the kidneys through processes like reabsorption and secretion. Hormones like antidiuretic hormone (ADH) and aldosterone play crucial roles in regulating water reabsorption and urine concentration, ensuring the body maintains proper fluid balance. Signup and view all the answers

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

The heart pumps blood, blood vessels carry blood, and blood transports oxygen, nutrients, hormones, and waste products. Signup and view all the answers

The kidneys in human beings are a part of which system?

Excretion Signup and view all the answers

The xylem in plants are responsible for the transport of which substance?

Water Signup and view all the answers

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

It is necessary to ensure that oxygen-rich blood is transported to body tissues while carbon dioxide-rich blood is filtered through the lungs for exchange. Signup and view all the answers

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

Highly organised plants have xylem and phloem for transport of water, nutrients, and sugars. Signup and view all the answers

The autotrophic mode of nutrition requires which of the following?

All of the above Signup and view all the answers

How are water and minerals transported in plants?

Water and minerals are transported through xylem tissue from roots to all parts of the plant. Signup and view all the answers

How is food transported in plants?

Food is transported through phloem tissue from leaves to other plant parts. Signup and view all the answers

Study Notes

Life Processes

Life processes are essential to maintain life and include nutrition, respiration, transportation, and excretion.
These processes are necessary to maintain a state of order in the body and to grow and develop.

What are Life Processes?

Life processes are the maintenance functions of living organisms that go on even when they are not doing anything particular.
These processes are necessary to prevent damage and break-down, and energy is needed for them.
The energy comes from outside the body of the individual organism, and there must be a process to transfer a source of energy from outside to the inside.

Nutrition

Nutrition is the process by which living organisms obtain energy and materials from outside.
Autotrophs, such as green plants and some bacteria, use simple food materials obtained from inorganic sources, such as carbon dioxide and water.
Heterotrophs, such as animals and fungi, utilise complex substances that have to be broken down into simpler ones before they can be used.
Bio-catalysts called enzymes are used to break down complex substances into simpler ones.

Autotrophic Nutrition

Autotrophic nutrition is the process by which autotrophs take in substances from the outside and convert them into stored forms of energy.
Photosynthesis is the process by which autotrophs take in carbon dioxide and water and convert them into carbohydrates in the presence of sunlight and chlorophyll.
Chlorophyll is essential for photosynthesis, and it absorbs light energy.
The energy from light is used to convert carbon dioxide and water into carbohydrates and oxygen.

Heterotrophic Nutrition

Heterotrophic nutrition is the process by which heterotrophs obtain energy and materials from outside.
Heterotrophs can be classified into different categories based on how they obtain their food, such as herbivores, carnivores, omnivores, and parasites.
Heterotrophs use different strategies to obtain their food, such as breaking down food material outside the body and then absorbing it, or taking in whole material and breaking it down inside their bodies.

How do Organisms obtain their Nutrition?

The way organisms obtain their nutrition differs, and the digestive system is different in various organisms.
In single-celled organisms, the food may be taken in by the entire surface.
In multicellular organisms, different parts become specialised to perform different functions.

Nutrition in Human Beings

The alimentary canal is a long tube that extends from the mouth to the anus.
The alimentary canal has different parts that are specialised to perform different functions.
Saliva contains an enzyme called salivary amylase that breaks down starch into simple sugar.
The stomach is a large organ that expands when food enters it, and the muscular walls of the stomach help in mixing the food thoroughly with more digestive juices.
Peristaltic movements occur all along the gut to move the food in a regulated manner along the digestive tube.### Digestion Process
Gastric glands in the stomach wall release hydrochloric acid, pepsin (protein-digesting enzyme), and mucus to facilitate digestion
- Hydrochloric acid creates an acidic medium for pepsin to act
- Mucus protects the inner lining of the stomach from acid under normal conditions
Food exits the stomach through a sphincter muscle, which releases it in small amounts into the small intestine
Small intestine is the longest part of the alimentary canal, fitted into a compact space due to extensive coiling
- Length of small intestine varies in animals depending on their diet (e.g., herbivores have longer small intestines to digest cellulose)

Digestion in the Small Intestine

Small intestine is the site of complete digestion of carbohydrates, proteins, and fats
Receives secretions from the liver and pancreas for digestion
- Bile juice from the liver makes food alkaline for pancreatic enzymes to act
- Bile salts break down fats into smaller globules, increasing enzyme efficiency (similar to soap's emulsifying action on dirt)
Pancreatic juice contains enzymes like trypsin for protein digestion and lipase for fat breakdown
Intestinal juice from the walls of the small intestine converts proteins to amino acids, complex carbohydrates to glucose, and fats to fatty acids and glycerol

Absorption in the Small Intestine

Digested food is absorbed through the walls of the small intestine
Inner lining of the small intestine has numerous finger-like projections (villi) that increase surface area for absorption
Villi are richly supplied with blood vessels that take absorbed food to every cell in the body

Respiration

Energy from food is used by cells to provide energy for various life processes
Diverse organisms use different pathways to break down glucose:
- Aerobic respiration (with oxygen): glucose → carbon dioxide + water + energy (ATP)
- Anaerobic respiration (without oxygen): glucose → ethanol + carbon dioxide (in yeast) or lactic acid (in muscles)

ATP and Energy

ATP (adenosine triphosphate) is the energy currency for most cellular processes
Energy released during respiration is used to synthesize ATP from ADP and inorganic phosphate
ATP is broken down to release energy that drives endothermic reactions in the cell

Breathing and Exchange of Gases

Terrestrial animals need to ensure sufficient oxygen intake
Plants exchange gases through stomata and have large intercellular spaces for diffusion
Animals have evolved different organs for oxygen uptake and carbon dioxide removal (e.g., lungs, gills)
Rate of breathing in aquatic organisms is much faster than in terrestrial organisms due to low oxygen levels in water

Human Respiratory System

Air is taken into the body through nostrils, filtered, and passed through the throat and lungs
Lungs have an extensive network of blood vessels and contain alveoli (balloon-like structures) for gas exchange
Alveoli provide a large surface area for oxygen absorption and carbon dioxide release
Haemoglobin in red blood corpuscles has a high affinity for oxygen and carries it to tissues

Transportation in Human Beings

Blood transports food, oxygen, and waste materials in the body
Plasma transports food, carbon dioxide, and nitrogenous wastes in dissolved form
Oxygen is carried by red blood corpuscles
Heart is a muscular organ that pumps blood around the body### The Heart and Blood Vessels
The heart has different chambers to prevent oxygen-rich blood from mixing with carbon dioxide-rich blood.
The oxygen-rich blood from the lungs comes to the left atrium, which then contracts and transfers the blood to the left ventricle.
The left ventricle then pumps the blood out to the body.
Deoxygenated blood from the body comes to the right atrium, which then contracts and transfers the blood to the right ventricle.
The right ventricle then pumps the blood to the lungs for oxygenation.
Valves in the heart ensure that blood does not flow backwards when the atria or ventricles contract.

Blood Pressure

Blood pressure is the force exerted by blood against the walls of blood vessels.
Systolic pressure is the pressure of blood inside the artery during ventricular contraction, while diastolic pressure is the pressure during ventricular relaxation.
Normal blood pressure is around 120 mmHg (systolic) and 80 mmHg (diastolic).
High blood pressure, also known as hypertension, can lead to the rupture of an artery and internal bleeding.

Blood Vessels

Arteries are thick-walled vessels that carry blood away from the heart to various organs.
Veins are thinner-walled vessels that collect blood from different organs and bring it back to the heart.
Capillaries are the smallest vessels, with walls that are one-cell thick, where exchange of materials between blood and surrounding cells takes place.
Platelets help to clot blood and plug leaks in the blood vessels.

Lymph

Lymph is a fluid that helps to transport nutrients and oxygen to cells and remove waste products.
Lymph is similar to plasma but contains less protein.
Lymph vessels drain into larger veins and finally open into the bloodstream.

Transportation in Plants

Plants have a system of transportation that moves energy stores from leaves to other parts of the plant.
The xylem transports water and minerals from the soil to the leaves.
The phloem transports products of photosynthesis from the leaves to other parts of the plant.
Transpiration is the process of water loss from the plant through evaporation, which helps to create a suction force that pulls water up from the roots.

Excretion

Excretion is the process of removing waste products from the body.
In humans, the excretory system includes the kidneys, ureters, urinary bladder, and urethra.
Kidneys filter out waste products from the blood, which are then removed from the body through urine.
Artificial kidneys can be used in cases of kidney failure to remove waste products from the blood through dialysis.

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Description

This quiz covers the basics of life processes, including the characteristics of living beings, breathing, and plant life.