Science [1 Mark Questions]

The growth movement in plants in response to chemical stimuli is known as chemotropism.

A reason is that multicellular organisms need special organs for exchange of gases with the environment because of prokaryotic cells found in the body. The cells are not in contact with the environment and therefore diffusion would not work in the exchange of gases.

Autotrophic mode of nutrition is the nutrition which is carried out by the auto tropes like green plants. Whereas heterotrophic mode of nutrition is the nutrition which is carried out by the hetero tropes like animals and humans.

The complete digestion of fats consumed by us takes place in the stomach and the small intestine.

The green dot-like structures in cells observed by a student when a leaf peel was viewed under the microscope were Chloroplast.
Green colour is due to Chlorophyll.

The spinal cord is protected by the vertebral column, and together with the brain it comprises the central nervous system.

The function of xylem in plants is to transport water from the roots to the different parts of the plant. Xylem is a tissue which, if removed from the plant, will stop the movement of water from the roots upwards and the plant will be die.

 

Evaporation/Excretion of water from aerial parts of plant is called transpiration.

1. Phloem.
2. Xylem.

1. Phloem.
2. Xylem.

Translocation.

Phloem.

Fat is present in the form of large globules. For the concerned enzyme, it is difficult to digest large globules of fat. Emulsification of fat results in fat breaking into smaller globules. After that, it becomes easier for the enzyme to digest fat.

Heart beat: One complete contraction and relaxation of the heart is called a heart beat. The usual heart beat rate at rest is 72 times/ minute.

Filtering unit of kidney is Nephron. It is composed of renal corpuscle (Bowman’s capsule + glomerulus) and renal tubules. kidney has millions of nephrons in the cortex and medulla region.Nephron has further parts Glomerulus, Bowmann's capsule etc.
Main function of nephron is filtration of urine which passes through various stages in nephron for purification.

Capillaries.

1. Respiration.
2. Photosynthesis.

Protein digestion occurs in the stomach and duodenum in which 3 main enzymes, pepsin secreted by the stomach and trypsin and chymotrypsin secreted by the pancreas, break down food proteins into polypeptides that are then broken down by various exopeptidases and dipeptidases into amino acids.

1. Water.
2. Food.

Chlorophy ll.

In the process of respiration, glucose is generally oxidized in the body. Examples of some respiratory substrates are glucose, proteins, fatty acids etc.

1. Glucose.
2. Starch.

Lungs.

Autotrophs are those organisms which can make their own food from carbon-dioxide and water.
Example: Green Plants.

Fish are vertebrates that have two-chambered hearts consisting of a single atrium and a single ventricle. The atrium is responsible for taking in returning blood from the body, while the ventricle's duty is to pump out blood that has entered the heart. But two chambered heart is less efficient because in two chambered heart mixing of oxygenated and deoxygenated blood occurs.

Amoeba has no fixed place for egestion. The undigested food gets collected inside amoeba, then its cell membrane suddenly ruptures and the undigested food is thrown out of the body of amoeba.

Hypertension.

Saprotrophic.

Blood and lymph.

Chlorophyll.

The kidney produce urine by removing toxic waste products and excess water from the body. Urine formed in each kidney passes through the ureter, flows into bladder before finally being excreted through the urethra. The kidneys are located at upper and back side of the abdomen, on either side of the spine.

Green.

Chlorophy ll.

Amoeba engulfs the food particles with the help of finger like projections called pseudopodia.

Blocked Stomata: It decreases the rate of photosynthesis by reducing gaseous exchange and non-cooling of leaves due to reduced transpiration.

Earthworm.

1. Oxygen.
2. Carbon-dioxide.

Small intestine.

Trypsin: It is a pancreatic enzyme present in the pancreatic juice. Its function is to digest the proteins.

Trachea.

The process of obtaining food is called phagocytosis, which means cell feeding.

Plants obtain food by a process called photosynthesis.

Root hair.

Ureters.

The heart beats faster when a person runs for a while because the body needs more energy under these conditions.

1. The teeth serve the function of mechanical digestion by chewing and grinding.
2. Three pairs of salivary glands in mouth secrete saliva which contain bicarbonate ions and salivary amylase. Salivary amylase starts the chemical digestion of starch into maltose in mouth itself.
3. Tongue serves in mixing of food with saliva.

When there is a kidney failure then dialysis machine is used. Dialysis cleans the blood of a person by separating the waste substance (urea) from the blood.

Large intestine.

Urea.