Bio QB
1. Common pathway for both aerobic and anaerobic respiration
The common pathway for aerobic and anaerobic respiration is glycolysis.
Glycolysis occurs in the cytoplasm of the cell.
It is the first stage of cellular respiration.
In this process glucose (6-carbon compound) is broken down.
It forms two molecules of pyruvic acid (3-carbon compound).
A small amount of ATP energy is produced.
Two molecules of ATP are formed in this process.
NADH molecules are also produced.
Glycolysis does not require oxygen.
Therefore it acts as the common pathway for both types of respiration.
2. Organism showing protonephridia
Protonephridia are excretory structures.
They are commonly found in flatworms.
A common example is Planaria.
Protonephridia consist of flame cells.
Flame cells contain beating cilia.
The cilia create a current of fluid movement.
They remove nitrogenous waste products.
They also maintain water balance in the body.
These structures open to the outside through excretory pores.
Thus protonephridia function in excretion and osmoregulation.
3. Phosphorylation
Phosphorylation is the addition of a phosphate group to a molecule.
It usually involves ADP converting into ATP.
It plays an important role in energy transfer in cells.
It occurs during cellular respiration.
It stores chemical energy in ATP.
ATP acts as the energy currency of the cell.
Phosphorylation occurs in mitochondria and cytoplasm.
There are different types of phosphorylation.
Examples include oxidative phosphorylation and substrate level phosphorylation.
This process is essential for metabolic activities.
4. Species of cockroach found in India
The common cockroach species in India is Periplaneta americana.
It is commonly called the American cockroach.
It belongs to Phylum Arthropoda.
Its body is elongated and flattened.
The colour is reddish brown.
The body is divided into head, thorax and abdomen.
It has three pairs of legs.
It has two pairs of wings.
It is usually found in dark and damp places.
It is a nocturnal insect.
5. Endocrine gland
Endocrine glands are ductless glands.
They release hormones directly into the blood.
Hormones regulate body functions.
These glands control growth and metabolism.
They help regulate reproductive processes.
Hormones travel through bloodstream to target organs.
Endocrine glands work slowly but for a longer time.
Examples include pituitary gland.
Another example is thyroid gland.
They form the endocrine system of the body.
6. Three domain system
The three domain system was proposed by Carl Woese.
It is a modern classification system.
It divides organisms into three domains.
These domains are Archaea.
Bacteria is the second domain.
Eukarya is the third domain.
This classification is based on genetic and molecular data.
Ribosomal RNA analysis was used.
It shows evolutionary relationships among organisms.
It is widely accepted in modern biology.
7. Percentage of CO₂ in atmosphere
Carbon dioxide is a component of Earth’s atmosphere.
Its concentration is about 0.03–0.04%.
It is produced during respiration of organisms.
It is also produced during burning of fuels.
Plants use CO₂ in photosynthesis.
It helps in the carbon cycle.
CO₂ traps heat in the atmosphere.
This produces the greenhouse effect.
Excess CO₂ causes global warming.
Therefore maintaining balance of CO₂ is important for life.
8. Taxonomy
Taxonomy is the science of classification of organisms.
It includes identification of organisms.
It also includes naming of organisms.
Organisms are grouped based on similar characteristics.
It helps in systematic study of biodiversity.
It helps scientists understand relationships among organisms.
Taxonomy uses binomial nomenclature.
It is important in biological research.
It helps in organising large numbers of species.
It forms the foundation of biological classification.
9. Disadvantages of vernacular names
Vernacular names are local names of organisms.
They vary from region to region.
The same organism may have different names in different places.
One name may refer to different organisms.
They cause confusion in scientific communication.
They are not universally accepted.
They are often not standardised.
Scientists cannot use them accurately in research.
Therefore scientific names are preferred.
Scientific names are universal and precise.
10. Tendon
Tendon is a fibrous connective tissue.
It connects muscle to bone.
It is composed of strong collagen fibres.
Tendons are strong and inelastic.
They transmit force from muscle to bone.
This helps in movement of body parts.
Tendons are found near joints.
They have very little elasticity.
Example is the Achilles tendon.
They play an important role in locomotion.
11. Structure of legs in cockroach
Cockroach has three pairs of legs.
Each pair of legs is attached to each thoracic segment.
The legs are used for walking and running.
Each leg is made up of five segments.
The first segment is coxa.
The second segment is trochanter.
The third segment is femur.
The fourth segment is tibia.
The last segment is tarsus, which has claws.
These legs help the cockroach move quickly on surfaces.
12. Photosynthesis (definition and reaction)
Photosynthesis is the process by which green plants prepare food.
It occurs in the chloroplasts of plant cells.
Plants use sunlight as a source of energy.
They use carbon dioxide from the air.
They also use water from the soil.
Chlorophyll absorbs light energy.
Glucose is produced as food for the plant.
Oxygen is released as a by-product.
It is the primary source of food and oxygen on Earth.
Chemical reaction:
[
6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2
]
13. Substrate level phosphorylation
Substrate level phosphorylation is a type of ATP formation.
It occurs during cellular respiration.
In this process ATP is formed directly.
A phosphate group is transferred from a substrate to ADP.
It does not require oxygen.
It occurs in the cytoplasm during glycolysis.
It also occurs in the Krebs cycle.
It produces a small amount of ATP.
No electron transport chain is involved.
It is an important method of energy production in cells.
14. Deamination
Deamination is the removal of amino group from amino acids.
It occurs mainly in the liver.
It is part of protein metabolism.
The amino group is removed as ammonia.
Ammonia is a toxic substance.
The liver converts ammonia into urea.
Urea is less toxic.
Urea is transported to kidneys through blood.
It is removed from the body in urine.
Thus deamination helps in nitrogen metabolism.
15. Ammonotelism, Ureotelism and Uricotelism
These are types of nitrogenous waste excretion.
Ammonotelism is the excretion of waste as ammonia.
Ammonia requires large amount of water for removal.
It is common in aquatic animals.
Example: fishes.
Ureotelism is the excretion of waste as urea.
It requires moderate amount of water.
It occurs in mammals and amphibians.
Uricotelism is the excretion of waste as uric acid.
It occurs in birds, reptiles and insects.
16. Lactic acid fermentation
Lactic acid fermentation is a type of anaerobic respiration.
It occurs in absence of oxygen.
Glucose is first converted into pyruvic acid.
Pyruvic acid is converted into lactic acid.
This process occurs in muscle cells.
It also occurs in some bacteria.
It produces small amount of ATP energy.
It occurs during vigorous exercise.
Accumulation of lactic acid causes muscle fatigue.
Oxygen later helps convert lactic acid back to pyruvate.
17. Carotenoids
Carotenoids are plant pigments.
They are found in chloroplasts and chromoplasts.
They produce yellow, orange and red colours.
They assist in photosynthesis.
They absorb light energy.
They transfer energy to chlorophyll.
They protect chlorophyll from damage by excess light.
They help prevent photooxidation.
Examples include carotene and xanthophyll.
They are important for plant metabolism.
18. Absorption spectrum and Action spectrum
Absorption spectrum shows wavelengths absorbed by pigments.
It is obtained using a spectrophotometer.
Different pigments absorb different wavelengths of light.
Action spectrum shows rate of photosynthesis at different wavelengths.
It measures effectiveness of light in photosynthesis.
It is obtained experimentally.
Chlorophyll absorbs mainly blue and red light.
Photosynthesis is highest in red and blue regions.
Action spectrum closely resembles absorption spectrum of chlorophyll.
Both help understand light reactions of photosynthesis.
19. Excitation of chlorophyll-a
Chlorophyll-a is the main photosynthetic pigment.
It absorbs light energy from the sun.
Light energy excites electrons of chlorophyll molecules.
Electrons move to higher energy levels.
These excited electrons are transferred to electron acceptors.
This starts the light reaction of photosynthesis.
Energy is used to form ATP molecules.
NADPH molecules are also produced.
These molecules are used in dark reactions.
Thus excitation of chlorophyll is essential for photosynthesis.
20. Body cavity of cockroach
The body cavity of cockroach is called haemocoel.
It is filled with haemolymph.
Haemolymph acts like blood in insects.
The haemocoel is divided into three sinuses.
The first is pericardial sinus.
The second is perivisceral sinus.
The third is perineural sinus.
These sinuses are separated by diaphragms.
Haemolymph circulates nutrients and wastes.
It also helps in transport within the body.
21. Smooth muscles
Smooth muscles are non-striated muscles.
They are involuntary muscles.
Their contraction is not under conscious control.
They are found in internal organs.
Examples include stomach and intestine.
They are also found in blood vessels.
Their cells are spindle-shaped.
They have single central nucleus.
They contract slowly and steadily.
They help in movement of internal organs.
22. Chemotaxonomy
Chemotaxonomy is a method of classification of organisms.
It is based on chemical constituents of organisms.
It studies proteins and enzymes.
It also studies secondary metabolites.
DNA and RNA analysis is also used.
It helps identify evolutionary relationships.
It is widely used in plant taxonomy.
It provides accurate classification.
It supports modern taxonomic studies.
It complements morphological classification.
23. Rules of binomial nomenclature
Binomial nomenclature is the scientific naming system.
Each organism has two names.
The first name represents the genus.
The second name represents the species.
The genus name begins with a capital letter.
The species name begins with a small letter.
Scientific names are written in italics.
When handwritten they are underlined separately.
The system was introduced by Carl Linnaeus.
It provides universal identification of organisms.
24. Areolar connective tissue
Areolar tissue is a loose connective tissue.
It is widely distributed in the body.
It is found between skin and muscles.
It contains fibroblast cells.
It also contains macrophages.
Fibres present include collagen and elastic fibres.
It acts as packing tissue.
It binds skin to underlying muscles.
It helps in repair of tissues.
It provides support and flexibility.
25. Mouth parts of cockroach
Cockroach has biting and chewing type mouthparts.
The first part is labrum (upper lip).
Labrum helps in holding food.
The second part is mandibles.
Mandibles are used for cutting and grinding food.
The third part is maxillae.
Maxillae help in handling food.
The fourth part is labium (lower lip).
Labium helps in manipulating food.
These parts together help in feeding process.
26. L.S. of kidney
Kidney is a bean-shaped excretory organ.
It is located in the abdominal cavity.
The outer region is called renal cortex.
The inner region is called renal medulla.
Medulla forms renal pyramids.
The pyramids open into minor calyces.
Minor calyces join to form major calyces.
These open into the renal pelvis.
Renal pelvis continues as ureter.
The kidney contains nephrons which form urine.
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