Plant Physiology Quiz

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Questions and Answers

What is osmotic pressure?

The pressure applied to pure solvent to prevent osmosis (correct)

The pressure required to move solutes against concentration gradient

The pressure that causes diffusion of water from high to low concentration

The pressure exerted by solid particles in a solution

Which pathway does water take when entering a root through osmosis?

Vascular pathway

Symplastic pathway (correct)

Transmembrane pathway

Apoplastic pathway

Which of the following is NOT a macro-nutrient for plants?

Magnesium

Iodine (correct)

Calcium

Nitrogen

What process describes the absorption of water through the cell wall of root hairs?

Imbibition (A) Signup and view all the answers

What commonly leads to an increase in osmotic pressure?

Increasing the solute concentration (D) Signup and view all the answers

Which elements are considered principal essential elements for plants?

Hydrogen, Oxygen, Carbon (D) Signup and view all the answers

What is the main function of the apoplastic pathway in water movement?

Movement of water through intercellular spaces (D) Signup and view all the answers

Which of the following elements is classified as a micro-nutrient?

Boron (A) Signup and view all the answers

What are trace elements in plants primarily known for?

Acting as activators for enzymes (B) Signup and view all the answers

What can result from the deficiency of macro and micro-nutrients in plants?

Disturbance in plant growth (A) Signup and view all the answers

How do minerals move from the soil to the plant cells?

Through diffusion and ion exchange (A) Signup and view all the answers

What process allows plants to absorb ions against the concentration gradient?

Active transport (D) Signup and view all the answers

What does the term 'selective permeability' refer to in the context of plant cell membranes?

The preference for certain ions over others (A) Signup and view all the answers

What occurs when a plant requires more of a substance already present in high concentration?

Active transport is employed to absorb more (C) Signup and view all the answers

In the experiment with the alga Nitella, what was demonstrated regarding ion concentration?

Cells utilize energy to achieve higher ion concentrations (B) Signup and view all the answers

What is released during aerobic respiration that is essential for active transport?

ATP (B) Signup and view all the answers

What distinguishes active transport from diffusion regarding energy dependence?

Active transport requires ATP, while diffusion does not. (A) Signup and view all the answers

Which part of the plant is primarily responsible for photosynthesis?

Green leaves and green herbaceous stems (C) Signup and view all the answers

Which statement about diffusion and active transport is correct?

Active transport requires a living membrane. (D) Signup and view all the answers

What is the main function of grana in the chloroplast?

To absorb light (C) Signup and view all the answers

What role does oxygen play in plant root salt absorption?

It is essential for aerobic respiration, which provides energy for absorption. (D) Signup and view all the answers

How does osmosis differ from imbibition?

Osmosis is specific to living cells; imbibition involves non-living materials. (B) Signup and view all the answers

What structure in chloroplasts increases surface area for light absorption?

Lamellae (D) Signup and view all the answers

What type of transport moves salts from soil into plant roots against concentration gradients?

Active transport (B) Signup and view all the answers

What occurs in the large intestine after undigested food is passed from the small intestine?

Absorption of water and minerals (A) Signup and view all the answers

What is the role of bacteria in the large intestine?

They decay the undigested food (B) Signup and view all the answers

What is the primary function of incisors in the mouth?

Cutting food (A) Signup and view all the answers

Which component does NOT facilitate the expelling of feces from the body?

Secretion of salivary amylase (B) Signup and view all the answers

Which type of gland is responsible for secreting saliva in the mouth?

Salivary glands (B) Signup and view all the answers

What is the function of maltase in the digestive process?

Hydrolyzes maltose to produce glucose (A) Signup and view all the answers

At what pH value does sucrase optimally function?

5.5 - 7.5 (A) Signup and view all the answers

What is the role of the epiglottis during swallowing?

To prevent food from entering the trachea (C) Signup and view all the answers

What is NOT a component of saliva?

Pepsin (C) Signup and view all the answers

Where is lipase primarily active in the digestive system?

Small intestine (C) Signup and view all the answers

What is the product of the reaction catalyzed by lactase?

Glucose and galactose (A) Signup and view all the answers

What type of muscle movement helps move food through the oesophagus?

Peristalsis (B) Signup and view all the answers

What is the pH level of saliva mentioned in the content?

Weakly alkaline (pH 7.4) (B) Signup and view all the answers

Which of the following enzymes is secreted by the pancreas?

Amylase (C) Signup and view all the answers

Which function does the oesophagus NOT perform?

Secrete digestive enzymes (B) Signup and view all the answers

Which of the following components helps in lubricating food for swallowing?

Mucus (A) Signup and view all the answers

Study Notes

Osmosis

Water diffuses from a low concentration of solute to a high concentration of solute.
Osmotic pressure is the pressure needed to prevent osmosis.
Osmotic pressure increases with increasing solute concentration.

Imbibition

Hydrophilic colloidal particles absorb liquids, causing them to swell.
Examples include cellulose, pectin, and protoplasmic proteins.

Water Absorption in Plants

Water enters the epidermis of roots through osmosis because the soil has a higher water concentration than the root cells.
Water moves from cell to cell through the cytoplasm—the symplastic pathway.
Cellulosic cell walls in root hairs absorb water by imbibition, and water then moves through the intercellular space, apoplastic pathway.

Mineral Requirements of Plants

Principal elements include hydrogen, oxygen, and carbon.
Macro-nutrients are magnesium, calcium, nitrogen, iron, sulfur, phosphorus, and potassium.
Micro-nutrients are aluminum, molybdenum, manganese, zinc, boron, iodine, chlorine, and copper.
These micro-nutrients are trace elements, needed in small quantities.
Micro-nutrients act as co-enzymes in the body, activating enzymes.
Mineral deficiencies can lead to disturbances in plant growth and a lack of flowers and fruit production.

Mineral Absorption Mechanism

Minerals are absorbed from the soil by diffusion through cell walls, moving from high concentration in the soil to low concentration in the cell wall.
Minerals are also taken up by the plant through a semi-permeable plasma membrane.
Active transport moves molecules across the membrane against the concentration gradient, using ATP from aerobic respiration.

Active Transport vs. Selective Permeability

An experiment using Nitella algae demonstrated the difference between active transport and selective permeability.
The concentration of some ions in the cell sap was higher than in the surrounding water, requiring active transport to move them across the membrane.
The unequal concentration of ions showed that the cell was selectively permeable to certain ions.

Photosynthesis in Plants

Photosynthesis occurs mainly in green leaves and stems because they contain chloroplasts.
Chloroplasts are structures within the cell where photosynthesis takes place.
Chloroplasts have a double membrane, a stroma, grana, and lamellae.
Lamellae increase surface area for absorbing light.

Digestion

The oral cavity is made up of teeth, a tongue, and salivary glands.
Teeth are distinguished by their shape and function, allowing for cutting, tearing, crushing, and grinding food.
The tongue is responsible for tasting and moving food in the mouth.
Salivary glands secrete saliva, which lubricates food, aids in swallowing, and initiates the breakdown of starch by salivary amylase (ptyalin).

Pharynx

The pharynx is a passageway for both food and air.
Swallowing is a reflex action triggered by the presence of food in the throat.
The epiglottis covers the trachea when swallowing, preventing food from entering.

Oesophagus

This 25cm tube extends from the neck to the stomach through the chest cavity.
Mucus glands help with the movement of food down the oesophagus.
Circular muscles responsible for peristalsis, a series of contractions and relaxations that move food to the stomach.
The oesophagus does not have a digestive function.

Large Intestine and Defecation

Undigested food passes from the small intestine to the large intestine.
Water and mineral absorption occur in the large intestine due to its convolutions.
Undigested food becomes semi-solid in the large intestine, where bacteria decompose it.
Mucus, contraction of the rectum, and relaxation of the anal sphincter muscles facilitate the expulsion of feces.

Enzyme Scheme

Ptyalin (salivary amylase) breaks down starch in the mouth.
Amylase (pancreatic amylase) breaks down starch in the duodenum.
Maltose is broken down by maltase.
Sucrose is broken down by sucrase.
Lactose is broken down by lactase.
Lipase is involved in the breakdown of emulsified fats and oils.

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Description

Test your knowledge on osmosis, imbibition, and water absorption in plants. This quiz covers the essential mineral requirements for plant growth and the various pathways water takes in the root system. Perfect for students studying plant biology!