FBISE Class 9th (SSC-l)

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FBISE Class 9th (SSC-l)

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A. Stomach
B. Lungs
C. Heart
D. Kidneys
Answer: Oxygen and carbon dioxide are exchanged between air and blood in the lungs.
A. Both are chemical processes
B. Breathing is gas exchange while cellular respiration releases energy chemically
C. Both release energy
D. Both occur in the mitochondria
Answer: Breathing is the physical exchange of gases, while cellular respiration is the chemical breakdown of glucose to release energy.
A. Produce more ATP directly
B. Regenerate NAD+ so glycolysis can continue
C. Store extra energy
D. Release oxygen
Answer: Reducing pyruvate regenerates NAD+, which is needed to keep glycolysis running in the absence of oxygen.
A. Glucose
B. Oxygen
C. Water
D. Carbon dioxide
Answer: Carbon dioxide is a raw material consumed in photosynthesis, not a product of it.
A. ATP
B. NADH and FADH2
C. Glucose
D. Carbon dioxide
Answer: NADH and FADH2 carry high-energy electrons and hydrogen to the electron transport chain.
A. Glucose
B. Oxygen
C. Energy
D. Starch
Answer: Energy in the form of ATP is one of the main products of aerobic respiration.
A. Glycolysis
B. Krebs cycle
C. Electron transport chain
D. Fermentation
Answer: Oxygen is consumed as the final electron acceptor in the electron transport chain.
A. Light cannot reach the chlorophyll
B. Enzymes of the Calvin cycle are denatured
C. Chlorophyll is completely used up
D. Stomata open too wide
Answer: The enzymes of the Calvin cycle denature above about 45 degree Celsius, halting the dark reactions.
A. Glucose
B. Chlorophyll
C. Water
D. Minerals
Answer: Glucose is the main fuel broken down during cellular respiration to release energy.
A. Light intensity is not limiting
B. Temperature is very low
C. Light is completely absent
D. Stomata are closed
Answer: Carbon dioxide can only accelerate photosynthesis if light and other factors are available in sufficient amounts.
A. The study of the functions and life processes of plants
B. The study of the classification of plants
C. The study of plant fossils
D. The naming and identification of plants
Answer: Plant physiology deals with how plants carry out vital life processes such as absorption, transport, photosynthesis and excretion.
A. Active transport
B. Osmosis
C. Diffusion of gases
D. Transpiration
Answer: Water enters root hairs by osmosis because the root hair cell sap is more concentrated than the soil water.
A. Xylem
B. Phloem
C. Epidermis
D. Cambium
Answer: Xylem conducts water and dissolved minerals upward from the roots to the leaves.
A. Cortex cells
B. Xylem cells
C. Epidermal cells of the root
D. Phloem cells
Answer: Root hairs are extensions of root epidermal cells that greatly increase the surface area for absorption.
A. Guttation
B. Transpiration
C. Osmosis
D. Respiration
Answer: Transpiration is the loss of water vapour, mainly through the stomata of leaves.
A. Dixon and Joly
B. Charles Darwin
C. Gregor Mendel
D. Robert Hooke
Answer: Dixon and Joly proposed the cohesion-tension theory to explain the upward movement of water in xylem.
A. Water molecules cohere to each other and adhere to xylem walls
B. Air bubbles carry water downward
C. Phloem pressure pushes water up
D. Root hairs actively pump water upward
Answer: Cohesive forces between water molecules and adhesion to the xylem walls keep a continuous water column.
A. Petiole
B. Epidermis, especially the lower surface
C. Midrib
D. Stem internodes
Answer: Most stomata are found in the lower epidermis of leaves where they allow gas exchange.
A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Hydrogen
Answer: Carbon dioxide diffuses into the leaf through stomata and is used to make glucose in photosynthesis.
A. Transpiration creates tension, which produces pull, so water rises
B. Water rises first, then tension and transpiration follow
C. Tension causes transpiration, which pulls water up
D. Pull creates transpiration, which produces tension
Answer: Evaporation from leaves creates tension; the pull is transmitted along the water column and water rises.