Questions and Answers
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
Because all cells of the body need oxygen, and simple diffusion would not be able to deliver enough oxygen to meet the requirements of all cells.
What criteria do we use to decide whether something is alive?
Visible movement, growth over time, presence of organised structures, and molecular movements within cells are criteria used to determine if something is alive.
What are outside raw materials used for by an organism?
Outside raw materials are used for energy production, growth, repair, and maintenance of living structures in organisms.
What processes would you consider essential for maintaining life?
Signup and view all the answers
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Signup and view all the answers
How is oxygen and carbon dioxide transported in human beings?
Signup and view all the answers
How are the lungs designed in human beings to maximize the area for exchange of gases?
Signup and view all the answers
What causes dental caries or tooth decay?
Signup and view all the answers
How does brushing teeth help prevent tooth decay?
Signup and view all the answers
What may happen if untreated dental decay allows microorganisms to invade the pulp?
Signup and view all the answers
In anaerobic respiration, what does pyruvate get converted into?
Signup and view all the answers
What is the primary function of ATP in cellular processes?
Signup and view all the answers
What are stomata and where are they present?
Signup and view all the answers
What causes the stomatal pore to open?
Signup and view all the answers
What is the purpose of potassium hydroxide in the experiment described in Figure 5.4?
Signup and view all the answers
Water used in photosynthesis is taken up by plants through their stems.
Signup and view all the answers
In the experiment described, sunlight is essential for ________________.
Signup and view all the answers
Match the following organisms with their nutritive strategies:
Signup and view all the answers
What is the function of the enzyme salivary amylase?
Signup and view all the answers
Describe the structure and functioning of nephrons.
Signup and view all the answers
What are the methods used by plants to get rid of excretory products?
Signup and view all the answers
How is the amount of urine produced regulated?
Signup and view all the answers
What are the components of the transport system in human beings? What are the functions of these components?
Signup and view all the answers
Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Signup and view all the answers
What are the components of the transport system in highly organised plants?
Signup and view all the answers
How are water and minerals transported in plants?
Signup and view all the answers
How is food transported in plants?
Signup and view all the answers
Study Notes
Life Processes
- Life processes are the functions that living organisms perform to maintain their internal environment and respond to changes in their external environment.
- These processes are essential for maintaining life and are necessary for growth, development, and survival.
Characteristics of Life
- Living organisms exhibit certain characteristics, such as:
- Movement, either visible or invisible (e.g. molecular movement)
- Growth and development
- Reproduction
- Response to stimuli
- Energy conversion and utilization
- Maintenance of homeostasis
Molecular Movement
- Molecular movement is necessary for life processes, as it allows for the exchange of materials and energy within the organism.
- This movement is not always visible, but it is essential for the functioning of cells and tissues.
Life Processes in Organisms
- Life processes are diverse and can vary depending on the type of organism, its environment, and its nutritional needs.
- Examples of life processes include:
- Nutrition: the process of obtaining and utilizing nutrients and energy
- Respiration: the process of exchanging oxygen and carbon dioxide
- Transportation: the movement of materials and energy within the organism
- Excretion: the removal of waste products
Nutrition
- Nutrition is the process of obtaining and utilizing nutrients and energy.
- Autotrophic organisms, such as plants, produce their own food through photosynthesis.
- Heterotrophic organisms, such as animals, obtain their food from external sources.
Photosynthesis
- Photosynthesis is the process by which autotrophic organisms convert light energy into chemical energy.
- The process requires:
- Light energy
- Carbon dioxide
- Water
- Chlorophyll
- The products of photosynthesis are:
- Glucose (a type of sugar)
- Oxygen
Autotrophic Nutrition
- Autotrophic organisms, such as plants, obtain their energy from sunlight and convert it into chemical energy through photosynthesis.
- Plants use carbon dioxide and water to synthesize glucose and oxygen.
Heterotrophic Nutrition
- Heterotrophic organisms, such as animals, obtain their food from external sources.
- Examples of heterotrophic nutrition include:
- Herbivory: obtaining food from plants
- Carnivory: obtaining food from animals
- Omnivory: obtaining food from both plants and animals
- Parasitism: obtaining food from another organism without killing it
Human Nutrition
- Human nutrition involves the process of obtaining and utilizing nutrients and energy from food.
- The alimentary canal is a long tube that extends from the mouth to the anus and is responsible for the digestion and absorption of nutrients.
- The digestive process involves:
- Mechanical digestion: breaking down food into smaller particles
- Chemical digestion: breaking down food into simpler molecules using enzymes
- Absorption: the uptake of nutrients into the bloodstream
- Assimilation: the use of nutrients by the body for energy and growth### Digestion and Absorption
- Gastric glands in the stomach wall release hydrochloric acid, pepsin, and mucus to facilitate digestion.
- Hydrochloric acid creates an acidic medium, which helps the enzyme pepsin break down proteins.
- Mucus protects the inner lining of the stomach from the acid.
Small Intestine
- The small intestine is the longest part of the alimentary canal, fitted into a compact space due to extensive coiling.
- Its length differs in various animals, depending on the type of food they eat.
- Herbivores, like those eating grass, need a longer small intestine to allow for cellulose digestion.
- Carnivores, like tigers, have a shorter small intestine since meat is easier to digest.
- The small intestine is the site of complete digestion of carbohydrates, proteins, and fats.
- It receives secretions from the liver and pancreas for digestion.
Digestive Enzymes
- Bile juice from the liver makes the food coming from the stomach alkaline, allowing pancreatic enzymes to act.
- Bile salts break down fats into smaller globules, increasing the efficiency of enzyme action.
- The pancreas secretes pancreatic juice containing enzymes like trypsin and lipase.
- Intestinal juice from the walls of the small intestine contains enzymes that convert proteins into amino acids, carbohydrates into glucose, and fats into fatty acids and glycerol.
Absorption
- The walls of the small intestine contain finger-like projections called villi, which increase the surface area for absorption.
- Villi are richly supplied with blood vessels, which take absorbed food to every cell of the body.
Respiration
- Respiration is the process of breaking down glucose to release energy.
- The first step in respiration is the breakdown of glucose into a three-carbon molecule called pyruvate.
- Pyruvate may be converted into ethanol and carbon dioxide in yeast during fermentation (anaerobic respiration).
- In the presence of oxygen, pyruvate is broken down into carbon dioxide and water in the mitochondria (aerobic respiration).
ATP
- ATP (adenosine triphosphate) is the energy currency for most cellular processes.
- The energy released during respiration is used to synthesize ATP from ADP and inorganic phosphate.
- ATP is broken down to release energy, which drives endothermic reactions in the cell.
Exchange of Gases
- In terrestrial organisms, oxygen is absorbed from the atmosphere and carbon dioxide is released.
- In aquatic organisms, oxygen is absorbed from the dissolved oxygen in water and carbon dioxide is released.
- The rate of breathing is faster in aquatic organisms due to the lower amount of dissolved oxygen in water.
Human Respiratory System
- The human respiratory system consists of nostrils, throat, lungs, and trachea.
- Air passes through the nostrils, filtered by fine hairs, and enters the lungs.
- The alveoli provide a large surface area for gas exchange.
- The blood brings carbon dioxide from the rest of the body and takes up oxygen in the alveoli.
Transport of Oxygen and Carbon Dioxide
- Oxygen is transported in the blood, bound to haemoglobin in red blood corpuscles.
- Carbon dioxide is mostly transported in the dissolved form in the blood.
- Haemoglobin has a high affinity for oxygen and releases it to tissues deficient in oxygen.
Heart and Circulatory System
- The heart is a muscular organ that pumps blood around the body.
- The blood transports food, oxygen, and waste materials to all the tissues.
- A network of tubes (blood vessels) reaches all the tissues, and a system is in place to repair damaged blood vessels.### Human Circulatory System
- The heart has different chambers to prevent oxygen-rich blood from mixing with carbon dioxide-rich blood.
- The left atrium collects oxygen-rich blood from the lungs, and the left ventricle pumps it to the rest of the body.
- The right atrium collects deoxygenated blood from the body, and the right ventricle pumps it to the lungs for oxygenation.
- Valves ensure that blood does not flow backwards when the atria or ventricles contract.
- The separation of the right and left sides of the heart allows for a highly efficient supply of oxygen to the body.
Double Circulation
- In double circulation, blood goes through the heart twice during each cycle.
- This is seen in vertebrates, including mammals and birds.
- In contrast, fish have a single circulation, where blood goes through the heart only once during each cycle.
Blood Pressure
- Blood pressure is the force exerted by blood against the walls of blood vessels.
- It is higher in arteries than in veins.
- Systolic pressure is the pressure in the arteries during ventricular contraction, while diastolic pressure is the pressure during ventricular relaxation.
- Normal systolic pressure is around 120 mmHg, and normal diastolic pressure is around 80 mmHg.
Blood Vessels
- Arteries carry blood away from the heart to various organs of the body.
- They have thick, elastic walls to withstand high blood pressure.
- Veins collect blood from different organs and bring it back to the heart.
- They have valves to ensure that blood flows only in one direction.
Transportation of Oxygen and Carbon Dioxide
- Oxygen-rich blood is pumped from the heart to the body.
- Carbon dioxide-rich blood is pumped from the body to the lungs.
- Oxygen is exchanged for carbon dioxide in the capillaries.
Lymphatic System
- Lymph is a fluid that circulates around the body and helps to transport digested and absorbed fat from the intestine.
- It drains excess fluid from the intercellular spaces back into the blood.
- Lymphatic vessels join larger veins to return the fluid to the blood circulation.
Plant Transportation
- Plants have a different transportation system than animals.
- They have a low energy requirement, so they use relatively slow transport systems.
- The xylem transports water and minerals from the roots to the leaves.
- The phloem transports products of photosynthesis from the leaves to other parts of the plant.
Transportation of Water in Plants
- Water is absorbed by the roots through a process called osmosis.
- The water is then transported to the xylem vessels, where it is pushed upwards by root pressure.
- Transpiration, the loss of water vapor from the leaves, helps to pull water up the xylem vessels.
Transportation of Food in Plants
- The phloem transports products of photosynthesis, such as sucrose, from the leaves to other parts of the plant.
- The phloem uses energy from ATP to transfer the sucrose into the phloem tissue.
- The increased osmotic pressure of the phloem tissue causes water to move into it, which pushes the sucrose to tissues with lower pressure.
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.
- The kidneys filter waste products from the blood, and the excess water is re-absorbed into the bloodstream.
Artificial Kidney (Hemodialysis)
- In case of kidney failure, an artificial kidney can be used to remove nitrogenous waste products from the blood.
- The artificial kidney contains tubes with a semi-permeable lining, suspended in a tank filled with dialysing fluid.
- The patient's blood is passed through the tubes, and the waste products are removed through diffusion.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz is about identifying the characteristics of living beings, including plants and animals, and understanding the processes that occur in them.