Class 10 Science Chapter 5 Practice Question Answers - Life Processes

Fill in the blanks

Q1: Plants get rid of excess water by ........................
Ans: Plants get rid of excess water by transpiration.
Transpiration is the process where:

• Water evaporates from plant leaves.
• This helps maintain water balance.
• It cools the plant and aids nutrient uptake.

Overall, transpiration is essential for plant health and growth.

Q2: ........................ and water are produced as wastes during respiration by plants.
Ans: CO₂ and water are produced as wastes during respiration by plants.

Q3: ........................ is produced as a waste during photosynthesis.
Ans: Oxygen is produced as a waste during photosynthesis.

Q4: The gaseous wastes of respiration and photosynthesis in plants are removed through the .................... in leaves and ....................... in stem and released to the air.
Ans: The gaseous wastes of respiration and photosynthesis in plants are removed through the stomata in leaves and lenticels in the stem, then released into the air.

Q5: The plants excrete CO₂ produced as a waste during .................. process in night time.
Ans: The plants excrete CO₂ produced as a waste during the respiration process at night.

Q6: Gums and resins are the ...................... products of plant.
Ans: Gums and resins are the waste products of plants.

Q7: The phenomenon of removal of waste products from the body is known as ......................
Ans: The phenomenon of the removal of waste products from the body is known as excretion.

Q8: Leaves of ...................... contain essential oils.
Ans: Leaves of tulsi and lemon contain essential oils.

Q9: ...................... are found in stem of conifers as waste product.
Ans: Resins are found in the stems of conifers as a waste product.

Q10: Aquatic plants lose most of their metabolic wastes by ...................... process.
Ans: Aquatic plants lose most of their metabolic wastes through the process of diffusion.

Match the Column

Match the items of Column A with items of Column B.

Ans:
A - (ii)
B - (iv)
C - (iii)
D - (i)

Very Short Answer Type Questions

Q1: Define nutrition.
Ans: Nutrition is the process by which organisms consume food and use its nutrients to support their bodily functions.

• It involves taking in food through eating.
• Nutrients from food are essential for growth, energy, and overall health.
• Proper nutrition helps maintain bodily functions and prevents diseases.

Q2: Name the enzymes present in the stomach.
Ans: Pepsin is the main enzyme found in the stomach. It plays a crucial role in the digestive process by breaking down proteins into smaller peptides.

• Pepsin: The primary enzyme for protein digestion.
• Gastric lipase: Helps digest fats.
• Renin: Assists in digesting milk proteins, primarily in infants.

These enzymes work together to ensure effective digestion in the stomach.

Q3: Which part of the body secretes bile? Where is bile stored?
Ans: Bile is secreted exclusively by the liver and is stored in the gall bladder.

Q4: Define peristalsis.
Ans: Peristalsis is the process by which food is moved through the digestive tract. It involves:

• Wave-like muscle contractions that push food along.
• Sequential contractions that occur in the oesophagus, stomach, and intestines.
• Essential for proper digestion and nutrient absorption.

This coordinated movement ensures that food is processed efficiently at each stage of digestion.

Q5: What is the emulsification of fat?
Ans: Emulsification is the process of breaking down large fat globules into smaller ones, making them soluble in water.

Q6: Name the enzyme present in human saliva. What type of food material is digested by this enzyme?
Ans: The enzyme present in human saliva is ptyaline, also known as salivary amylase. This enzyme plays a key role in the digestion of:
Starch
Ptyaline begins the process of starch digestion in the mouth.

Q7: Define assimilation.
Ans: Assimilation refers to the process of the body or any biological system absorbing and digesting food or nutrients.

Q8: Name the most common method of ingestion in Amoeba.
Ans: Phagocytosis is the primary method of ingestion in Amoeba.

Q9: Why is the food vacuole of Amoeba called a temporary stomach?
Ans: In amoeba, the food vacuole acts as a temporary stomach because:

• It forms when the amoeba engulfs food.
• After digestion, the vacuole dissolves.
• A new food vacuole is created for each meal.

This cycle of formation and disappearance is why it is referred to as a 'temporary stomach'.

Q10: Name different types of teeth present in man.
Ans: Different types of teeth present in man:

• Eight incisors: Four in the upper jaw and four in the lower jaw, designed for cutting food.
• Four canines: Pointy teeth located next to the incisors, used for tearing food.
• Eight premolars: Found next to the canines, these teeth are used for grinding food.
• Twelve molars: Located at the back of the jaw, next to the premolars, these teeth also include four wisdom teeth.
  

Q11: Which part of the alimentary canal is adapted for complete digestion and absorption of food?
Ans: The small intestine is specifically adapted for the complete digestion and absorption of food. It plays a crucial role in the digestive process due to the following features:

• Surface area: It has a large surface area, enhanced by villi and microvilli, which maximises nutrient absorption.
• Digestive enzymes: It secretes various enzymes that break down food into smaller nutrients.
• Length: Its length allows sufficient time for digestion and absorption to occur.
• Muscle contractions: Peristaltic movements help mix and propel food along the canal.

These adaptations make the small intestine essential for effective digestion and nutrient uptake.

Q12: What is succus entericus?
Ans: Succus entericus is an alkaline secretion produced by glands in the duodenum wall. It includes:

• Water
• Mucoproteins
• Hydrogen carbonate ions

This intestinal juice, secreted by Lieberkuhn's crypts, serves several important functions:

• Neutralises the highly acidic chyme from the stomach.
• Protects the duodenum from potential damage.
• Facilitates digestion within the small intestine.

Q13: Name the largest gland of the human body.
Ans: The liver is the largest gland in the human body.

Q14: Name the protein-digesting enzymes present in the pancreatic juice of man.
Ans: Trypsin is a key protein-digesting enzyme found in human pancreatic juice.

• It helps break down proteins into smaller peptides.
• Produced in an inactive form called trypsinogen.
• Activated in the small intestine for digestion.

Q15: What are the end-products of fat digestion?
Ans: Fats are digested primarily in the small intestine. During digestion, one triglyceride molecule is broken down into:

• Three fatty acid molecules
• One glycerol molecule

The liver produces bile, which aids in the digestion of fats and some vitamins.

Short Answer Type Questions

Q1: Describe various modes of nutrition.
Ans: Nutrition is mainly divided into two categories:
Autotrophic mode of nutrition:

• Phototrophic: Organisms prepare their own food using sunlight, water, and carbon dioxide. Example: Green plants.
• Chemotrophic: Organisms create their own food using chemicals like nitrate, hydrogen sulphate, iron, and sulphur. Example: Bacteria.

Heterotrophic mode of nutrition:

• Holozoic: Animals consume solid food, involving five digestion stages: ingestion, digestion, absorption, assimilation, and egestion. Example: Humans.
• Saprophytic: Organisms feed on dead and decaying organic matter, breaking down complex food into simpler forms before ingestion. Example: Decomposers.
• Parasitic: Organisms obtain nutrients from other living organisms. The parasite lives inside a host organism and derives nutrients from it. Example: Tapeworm.

Q2: Mention various steps of nutrition in Amoeba.
Ans: Amoeba exhibits a type of nutrition known as holozoic nutrition, which involves the ingestion of solid or liquid food. The steps involved in this process are as follows:

• Ingestion: The amoeba surrounds and takes in food through its cell membrane.
• Digestion: Enzymes break down the food within food vacuoles.
• Absorption: Nutrients from the digested food are absorbed into the cytoplasm.
• Assimilation: The absorbed nutrients are incorporated into the amoeba's cells for energy and growth.
• Egestion: Undigested material is expelled from the cell.

Q3: Draw the position of salivary glands in the mouth.
Ans:

Q4: What is the role of hydrochloric acid in our stomach?
Ans: Hydrochloric acid plays a crucial role in the stomach by:

• Creating an acidic environment in the stomach.
• Killing harmful microbes that enter with food.
• Providing the right conditions for the enzyme pepsin to digest food.

Q5: State two functions of the large intestine of man.
Ans: The large intestine has two main functions:

• It stores waste food materials until they are eliminated.
• It reabsorbs water and salts that remain after digestion.

Q6: What criteria do we use to decide whether something is alive?
Ans: All living organisms are composed of cells and exhibit specific characteristics that indicate life. These include:

• Visible movement: Such as walking, breathing, or growing.
• Invisible processes: Movements that cannot be seen with the naked eye.
• Life processes: Essential functions like respiration, nutrition, and reproduction.

The presence of these life processes is a key criterion to determine if something is alive.

Q7: What are the differences between autotrophic nutrition and heterotrophic nutrition?
Ans:

Q8: How is the small intestine designed to absorb digested food?
Ans: The small intestine is crucial for the digestion and absorption of food. It consists of three main sections:

• Duodenum: A U-shaped section.
• Jejunum: A long, coiled middle part.
• Ileum: A highly coiled end section.

The innermost layer, known as the mucosa, has special adaptations:

• Irregular folds called rugae in the stomach.
• Finger-like projections called villi in the small intestine.

These structures significantly increase the surface area for absorption. Each villus contains:

• A network of capillaries for nutrient transport.
• A large lymph vessel called the lacteal for lipid absorption.

The walls of the small intestine are surrounded by blood vessels that distribute absorbed food molecules throughout the body.

Q9: What is the difference between ingestion and egestion?
Ans:

• Ingestion: Taking in complex organic food by the organism is called ingestion.
• Egestion: The elimination of undigested waste and food materials from the body is called egestion.

Q10: How can dental caries be prevented?
Ans: Dental caries can be prevented by following these key practices:

• Avoiding acidic foods and drinks that can harm tooth enamel.
• Maintaining a regular dental hygiene routine, including brushing twice a day.
• Flossing daily to remove food particles and plaque between teeth.
• Regular visits to the dentist for check-ups and cleanings.

By implementing these steps, you can significantly reduce the risk of dental caries.