Life Processes and Characteristics

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Questions and Answers

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

Criteria include movement, growth, respiration, and reproduction.

What are outside raw materials used for by an organism?

Outside raw materials are used for energy, growth, and cellular functions.

What processes would you consider essential for maintaining life?

Essential processes include nutrition, respiration, and excretion.

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

Diffusion is insufficient because it cannot transport oxygen efficiently to all cells due to their complexity and size. Signup and view all the answers

What is the role of the acid in our stomach?

The acid creates an acidic medium that facilitates enzyme action and helps digest food. Signup and view all the answers

What is the function of digestive enzymes?

Digestive enzymes break down complex food molecules into simpler ones for absorption. Signup and view all the answers

How is the small intestine designed to absorb digested food?

The small intestine has villi that increase surface area for absorption and are richly supplied with blood vessels. 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 for energy. Signup and view all the answers

What are the differences between autotrophic nutrition and heterotrophic nutrition?

Autotrophic nutrition involves producing food from inorganic sources, while heterotrophic nutrition involves obtaining food from other organisms. Signup and view all the answers

What change is observed in the lime water and how long does it take for this change to occur when carbon dioxide is bubbled into it?

Lime water turns milky upon contact with carbon dioxide, indicating the presence of the gas. Signup and view all the answers

What does the fermentation of fruit juice or sugar solution with yeast produce?

Fermentation produces carbon dioxide and ethanol. Signup and view all the answers

What are the main products of aerobic respiration?

The main products of aerobic respiration are carbon dioxide and water. Signup and view all the answers

What advantage does a terrestrial organism have over an aquatic organism in obtaining oxygen for respiration?

Terrestrial organisms can directly utilize the oxygen in the air, which is generally more abundant than dissolved oxygen in water. 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 aerobic respiration, anaerobic respiration, fermentation, or other metabolic pathways. Signup and view all the answers

How is oxygen and carbon dioxide transported in human beings?

Oxygen is transported by red blood cells using hemoglobin, while carbon dioxide is mostly transported dissolved in plasma or as bicarbonate ions. Signup and view all the answers

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

The lungs contain alveoli, which are balloon-like structures that provide a large surface area for gas exchange. Signup and view all the answers

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

Components include the heart, blood vessels (arteries, veins, capillaries), and blood. The heart pumps blood, blood vessels carry blood, and blood transports nutrients, gases, and waste. Signup and view all the answers

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

It is necessary to prevent mixing to maintain an efficient supply of oxygen to the body and ensure that tissues receive oxygen-rich blood. Signup and view all the answers

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

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

How are water and minerals transported in plants?

Water and minerals are primarily absorbed through the roots and transported upward through the xylem. Signup and view all the answers

How is food transported in plants?

Food is transported through the phloem via a process called translocation, which involves the movement of soluble products of photosynthesis. Signup and view all the answers

How is urine produced in human beings?

Urine is produced through the filtration of blood in the kidneys, where waste products are removed and excess substances are excreted. Signup and view all the answers

Describe the structure and functioning of nephrons.

Nephrons are the functional units of kidneys, consisting of a glomerulus for filtration and tubules for reabsorption and secretion. Signup and view all the answers

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

Plants excrete waste by transpiration, storing waste in vacuoles or dead cells, and shedding leaves. Signup and view all the answers

How is the amount of urine produced regulated?

The amount of urine produced is regulated by the balance of water and electrolytes in the body, controlled by hormones like aldosterone. 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 is 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 lipases in the small intestine. Signup and view all the answers

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

Saliva moistens food and contains enzymes 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?

Necessary conditions include sunlight, carbon dioxide, and water; by-products are oxygen and glucose. Signup and view all the answers

What are the differences between aerobic and anaerobic respiration?

Aerobic respiration requires oxygen and produces more ATP; anaerobic respiration occurs without oxygen and produces less ATP. 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 are surrounded by capillaries for efficient gas exchange. Signup and view all the answers

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

A deficiency of hemoglobin can lead to anemia, causing fatigue, weakness, and reduced oxygen transport. Signup and view all the answers

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

Double circulation involves the separation of pulmonary and systemic circuits, ensuring efficient oxygenation of blood. Signup and view all the answers

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

Xylem transports water and minerals upwards, while phloem transports glucose and nutrients in both directions. 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.

Alveoli facilitate gas exchange with a large surface area and thin walls, while nephrons filter blood and reabsorb essential substances. Signup and view all the answers

Study Notes

Characteristics of Life

Movement is a common characteristic of living beings, but it is not a defining characteristic
Even when a living organism is asleep, it still performs maintenance functions that keep it alive
Molecular movements are necessary for life, and are present in all living organisms

Life Processes

Life processes are the maintenance functions that all living organisms perform to stay alive
These processes are necessary to prevent the breakdown of the organism's structure
Energy is needed to perform these processes, and is obtained from outside the body

Nutrition

Nutrition is the process by which living organisms obtain energy and materials from the environment
There are two types of nutrition: autotrophic and heterotrophic
Autotrophic organisms (e.g. plants) make their own food using sunlight and carbon dioxide
Heterotrophic organisms (e.g. animals) obtain energy and materials from other organisms

Autotrophic Nutrition

Autotrophic organisms use photosynthesis to convert sunlight and carbon dioxide into energy
Photosynthesis occurs in specialized organelles called chloroplasts
Chlorophyll is essential for photosynthesis
Carbon dioxide and water are absorbed by the plant and converted into carbohydrates

Heterotrophic Nutrition

Heterotrophic organisms obtain energy and materials from other organisms
There are several strategies for heterotrophic nutrition, including:
- Breaking down food outside the body and then absorbing it (e.g. fungi)
- Taking in whole food particles and breaking them down inside the body (e.g. animals)
- Deriving nutrition from plants or animals without killing them (e.g. parasites)

Digestive System

The digestive system is specialized to break down food and absorb nutrients
In single-celled organisms, food is taken in by the entire surface of the cell
In multi-celled organisms, different parts of the body become specialized to perform different functions
In humans, the alimentary canal is a long tube that extends from the mouth to the anus, with different regions specializing in different functions

Human Digestion

The mouth breaks down food using teeth and saliva
Saliva contains enzymes that break down starches into simpler sugars
The broken-down food is then absorbed into the bloodstream and transported to the rest of the body### Digestion and Absorption
Food consumption: Saliva is secreted by salivary glands, containing an enzyme called salivary amylase that breaks down starch into sugar.
Mechanical digestion: Food is mixed with saliva by the muscular tongue while chewing, and then swallowed.
Peristaltic movements: Muscles in the lining of the alimentary canal rhythmically contract to push food forward through the digestive tube.
Stomach: Muscular walls mix food with digestive juices, including hydrochloric acid and pepsin, which facilitate protein digestion.
Small intestine: Longest part of the alimentary canal, with a large surface area for absorption due to extensive coiling and villi (finger-like projections).
Digestion and absorption: Enzymes from the liver and pancreas break down carbohydrates, proteins, and fats, which are then absorbed into the bloodstream.

Respiration

Breathing: Oxygen is taken in and carbon dioxide is released through the mouth and nostrils, filtered and moisturized in the throat and lungs.
Lung structure: Alveoli provide a large surface area for gas exchange, with an extensive network of blood vessels for oxygen and carbon dioxide transport.
Respiratory pigments: Haemoglobin in red blood cells has a high affinity for oxygen, carrying it from the lungs to tissues and releasing it.
Carbon dioxide transport: Mostly dissolved in water, with some bound to haemoglobin.

Transportation in Human Beings

Blood composition: Plasma (fluid medium) transports food, oxygen, and waste materials, while red blood cells carry oxygen.
Haemoglobin: Normal range in human beings varies by age and sex, with differences in levels between children and adults, men and women.
Haemoglobin levels in animals: Vary by species, age, and sex, with differences in levels between calves, male and female animals.### The Heart and Circulation
The heart is a muscular organ that pumps blood throughout the body.
The heart has different chambers to prevent oxygen-rich blood from mixing with carbon dioxide-rich blood.
Oxygen-rich blood from the lungs comes to the left atrium, then to the left ventricle, and is pumped out to the body.
De-oxygenated blood comes from the body to the right atrium, then to the right ventricle, and is pumped to the lungs for oxygenation.

Blood Pressure

Blood pressure is the force of blood against the walls of blood vessels.
Blood pressure is higher in arteries than in veins.
Systolic pressure is the pressure during ventricular contraction, and diastolic pressure is the pressure during ventricular relaxation.
Normal blood pressure is around 120/80 mmHg.

Blood Vessels

Arteries carry blood away from the heart to the organs.
Arteries have thick, elastic walls to withstand high pressure.
Veins collect blood from organs and bring it back to the heart.
Veins have valves to ensure blood flows in one direction.

Capillaries

Capillaries are the smallest blood vessels, with walls one-cell thick.
Exchange of materials between blood and surrounding cells takes place across the thin walls of capillaries.

Platelets and Lymph

Platelets help to clot blood and plug leaks in blood vessels.
Lymph is a fluid that drains from tissues and returns to the blood.
Lymph carries digested and absorbed fat from the intestine and drains excess fluid from extracellular spaces back into the blood.

Transportation in Plants

Plants have a separate system of transportation for energy and raw materials.
Xylem tissue transports water and minerals from roots to leaves.
Phloem tissue transports products of photosynthesis from leaves to other parts of the plant.
Transpiration helps to move water and minerals from roots to leaves.

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 and produce urine.
Urine is stored in the urinary bladder and released through the urethra.

Kidneys and Urine Production

Nephrons are the basic filtration units in the kidneys.
Each nephron consists of a cluster of thin-walled blood capillaries and a cup-shaped end of a tube that collects the filtered urine.
Substances such as glucose, amino acids, salts, and water are selectively re-absorbed as the urine flows along the tube.

Artificial Kidney (Hemodialysis)

Artificial kidneys can be used in case of kidney failure.
Hemodialysis helps to remove waste products from the blood when the kidneys are not functioning properly.

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Description

Explore the essential characteristics and processes that define life, including movement and maintenance functions. Learn how these processes keep living organisms alive.