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Tuesday, 21 May 2024

Nervous Coordination (Chapter No.17) - MCQs Biology Book Two (English) - Class 2nd Year (XII or 12th) Science Group

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Chapter No.17
Nervous Coordination

Multiple Choice Questions

1. Encircle the correct choice:
i) Most of the neurons in the human brain are:
a) Sensory neurons
b) Motor neurons
c) Interneurons ✔
d) Auditory neurons

ii) A nervous system can alter activities in its target cells in muscles and gland because:
a) They are electrically coupled by gap junctions.
b) The target cells have receptor proteins for signal released by the nervous system. ✔
c) The nervous system releases signals into the blood to control the target cells.
d) The target cells that become disconnected from the nervous system rapidly die.

iii) For a neuron with an initial membrane potential at -70mv, an increase in the movement of potassium ions out of that neuron’s cytoplasm would result in:
a) Depolarization of the neuron
b) Hyperpolarization of neuron ✔
c) The replacement of potassium ions with sodium ions.
d) The replacement of potassium ions with calcium ions.

iv) Action potentials move along axons.
a) More slowly in axons of large than in small diameter.
b) The direct action of acetylcholine on the axon membrane.
c) Activating the sodium-potassium pump at each point along the axon membrane.
d) More rapidly in myelinated than in non-myelinated axons. ✔

v) The surface on a neuron that discharges vesicles is the:
a) Dendrite
b) Axon hillock
c) Presynaptic membrane ✔
d) Postsynaptic membrane

vi) An inhibitory postsynaptic potential occurs in a membrane made more permeable to:
a) Potassium ions ✔
b) Sodium ions
c) Calcium ions
d) ATP

vii) The major inhibitory neurotransmitter of the brain is:
a) Acetylcholine
b) Epinephrine
c) GABA ✔
d) Endorphin

viii) Where are neurotransmitter receptors located:
a) On the nuclear membrane
b) In the myelin sheath
c) At nodes of Ranvier
d) On the postsynaptic membrane ✔

ix) Which selection is incorrectly paired?
a) Forebrain ⟶ Diencephalon
b) Forebrain ⟶ Cerebrum
c) Midbrain ⟶Brainstem
d) Midbrain ⟶ Cerebellum ✔

x) Which of the following receptors is incorrectly paired with the type of energy is transduces?
a) Mechanoreceptors ⟶ Sound
b) Pain receptors — Electricity ✔
c) Chemoreceptors ⟶ Solute concentration
d) Thermoreceptors ⟶ Heat

Important Points To Remember:

Nervous co-ordination mainly comprises on highly specialized cells, called neurons.
All receptors are transducers that convert signals from one form to another form.
Schwan cells produce myelin in peripheral nervous system (PNS).
Oligodendrocytes produce myelin in central nervous system (CNS).
Nerve impulse is an electrical signal that depends on the flow of ions across the membrane of a neuron.
The voltage measured across the plasma membrane is called membrane potential and it is typically in the range from -50mv to -100mv in an animal cell.
Action potential is a sudden reversal of the electrical charge across the membrane, triggered by a temporary, localized increase in its permeability to sodium.
Depolarization makes the membrane potential less negative.
Hyperpolarization makes the membrane potential more negative.
The level of depolarization needed to produce an action potential is called threshold potential.
Velocity of conduction is greater if the diameter of the axon is larger or if the axon is myelinated.
Synapse is junction that control communication between a neuron and another cell.
The movement of impulse across the synapse is called a synaptic transmission.
Electrical synapse involves direct cytoplasmic connections formed by gap junctions between the presynaptic neuron and postsynaptic neurons.
Biogenic amines are neurotransmitters derived from amino acids most commonly function as transmitters within the CNS.
Human nervous system consists of central nervous system and peripheral nervous system.
Central nervous system is integrating portion of the nervous system.
CNS stands for central nervous system.
PNS stands for peripheral nervous system.
RMP stands for resting membrane potential.
AMP stands for action membrane potential.
EPSP stands for excitatory postsynaptic potential.
IPSP stands for inhibitory postsynaptic potential.
GABA stands for gamma aminobutyric acid.
CSF stands for cerebrospinal fluid.
EEG stands for Electro encephalo gram.
CT stands for Computed tomography.
MRI stands for Magnetic resonance imaging.

Support And Movement (Chapter No.16) - MCQs - Biology Book Two (English) - Class 2nd Year (XII or 12th) Science Group

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Chapter No.16
Support And Movement

Multiple Choice Questions

1. Encircle the correct choice:
i) The type of bone cell that tears down bone during the building and remodelling process are:
a) Osteocytes
b) Osteoblasts
c) Osteoclasts ✔
d) Bone lining cells

ii) During bone formation, as the periosteum calcifies. it gives rise to a thin plate of compact bone called:
a) Periosteal bud
b) Periosteal bone collar ✔
c) Primary ossification center
d) Epiphyseal plate

iii) The ring like shape of the girdle is due to the joining of coxal bone with the sacrum of vertebral column at anterior side and below by a joint in between pubic part called:
a) Pubic symphysis ✔
b) Iliac junction
c) Pelvic symphysis
d) Syndesmosis

iv) Cartilage is a soft flexible form of connective tissue Surrounded by a layer called:
a) Myocardium
b) periosteum
c) Osteoderm
d) Perichondrium ✔

v) An antagonist muscle is relaxed while the other side opposite to antagonist muscle:
a) Contracted ✔
b) Relaxed
c) No change
d) Extremely relaxed

vi) The stage when old bone tissues are removed and gets replaced with new ones that joins both fractured sides called:
a) Bone remodeling stage ✔
b) Bone callus formation
c) Cartilaginous callus formation
d) Hematoma formation

vii) Which is related to the mild to severe grade of stretching or tearing of a ligament that holds the bones of a joint together?
a) Spasm
b) Tetany
c) Sprains ✔
d) Cramps

viii) Muscle fiber are gathered in many groups each group of fibers is called a fascicle which is surrounded by a membrane called:
a) Sarcolemma
b}Perimysium ✔
c) Endomysium
d) Epimysium

ix) The heart muscles arranged in a branching network where cells are joined together and making a:
a) Syncytium ✔
b) Sarcoplasmic reticulum
c) Endoplasmic reticulum
d) T-tubules

x) These joints hold the bone by dense connective tissue contain collagenous fibers:
a) Fibrous joints ✔
b) Syndesmosis
c) Gamphosis
d) Synovial joints

Important Points To Remember:

Human skeleton acts as a framework of the body.
The study of human bones is called osteology.
Bone has distinct regions called epiphysis, diaphysis and metaphysis and covered by different layers.
Bones and cartilage are composed of numerous cells.
Different types of cartilages are located in skeleton and plays vital role in protecting joints.
Human skeleton is formed by numerous bones and has two major divisions called axial and appendicular skeleton which include separate bones.
Bones are joined to form different joints.
The major groups of joints are called fibrous, synovial and cartilaginous joints.
The common disorders of the skeletal system are disc slip, spondylosis, sciatica, and arthritis.
Repair of several types of bone fracture takes place m different steps in sequence i.e., hematoma formation, internal and external callus formation, replacement of cartilage by trabecular bone and remodeling.
First-aid treatment is also used for the injuries in joints like dislocation and sprain.
There are three types of muscles in the body that perform movement.
Skeletal muscles are present in organs that work voluntarily.
Non-skeletal muscles are present in organs that work in involuntary organs.
Cardiac muscles are present in heart.
Skeletal muscle fiber contains numerous myofibril.
Myofibril contain two kinds of protein filaments namely actin and myosin.
Actin and myosin filaments are cross linked and perform muscles contraction.
Out to abnormal muscle contraction teeny and cramps takes place.
ADP stands for Adenosine diphosphate.
ATP stands for Adenosine triphosphate.
'A' band stands for Anisotropic band.
'I' band stands for Isotropic band.
"H" zone stands for Helle Zone.
"M" line or Disc stands for Myomesin line or disc.
(Tn-C) stands for Troponin C.
(Tn-I) stands for Troponin I.
(Tn-T) stands for Troponin T.
"Z" line or Disc stands for Zwischen line or disc.

Homeostasis (Chapter No.15) - MCQs - Biology Book Two (English) - Class 2nd Year (XII or 12th) Science Group

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Chapter No.15
HOMEOSTASIS

Multiple Choice Questions

1. Encircle the correct choice:
i) A self-regulating process by which biological systems maintain stability while adjusting to the changing conditions called:
a) Homeostasis ✔
b) Osmoregulation
c) Excretion
d) Biological rhythms

ii) Which does not maintain a stable, homeostatic condition rather it intensifies the change that is happening to the body:
a) Negative feedback
b) Positive feedback ✔
c) Feedback system
d) Excretion

iii) Freshwater organisms also have specialized cells located in their gills and in skin which actively extract Na⁺, Cl^- and Ca⁺⁺ from external medium and excrete (H⁺)or basic (HCO₃^-) for acid base balance in the body fluids are called:
a) Granulocyte
b) Lymphocyte
c) Ionocytes ✔
d) podocyte

iv) Renal cortex produces, an important hormone necessary for the synthesis of RBC’s:
a) Erythropoietin ✔
b) Leukoopoietin
c) Thrombopoietin
d) Renin

v) Glomerulus have specialized cells that are wrapped around blood capillaries that play an active role 1n preventing plasma proteins from entering the urinary ultrafiltrate called:
a) Epithelial cells
b) Podocyte cells ✔
c) Endothelial cells
d) None of them

vi) Tubules secretes ions such as hydrogen, potassium, and NH₃ into the filtrate while reabsorbing the HCO₃^- from the filtrate are called:
a) Distal convoluted tubule
b) Proximal convoluted tubule ✔
c) Collecting duct
d) Loop of Henle

vii) Glomerular Filtration rate (GFR) is in which proportional to the hydrostatic pressure exerted in glomerulus wall:
a) Indirectly proportional
b) Directly proportional ✔
c) Same proportional
d) High proportional

viii) Another Compound that increases the osmotic gradient in inner medulla is the:
a) Urea ✔
b) Water
c) Sulphates
d) Phosphates

ix) The inflammation in Kidneys due to irritation of kidney stones is called:
a) Lithonephritis ✔
b) Edema
c) Sarcoma
d) Encephalitis

x) If the surrounding environment becomes hot or a person do strenuous physical activity the heat produced inside the body and raises body temperature above suitable suitable limit this condition is called:
a) Exothermia
b) Hyperthermia ✔
c) Hypothermia
d) Endothermia

Important Points To Remember:

Homeostasis is process by which biological systems maintain stability while adjusting to the changing conditions.
Feedback, in biology, is a response within a system.
There are two types of feedback mechanisms that counter act upon each other called positive and negative feedback.
Freshwater and marine water animals adjust their osmotic internal environment according to the changing external environment primarily by excretion.
Animals produce different types of excretory waste to regulate their internal homeostatic environment.
Urinary system is not only used for removing waste from the body, but also maintains the acid base balance of the body.
Urinary system formed by mainly a pair of kidneys and associated organs.
Kidney performs different functions including ultra filtration, selective reabsorption and counter current mechanism.
Diseases of urinary tract are caused by bacteria and viruses that invade or enters through anus or urethral opening and by other means.
Urine contains many dissolved mineral and salts that form different compounds.
Kidney failure is treated by are hemodialysis, continuous renal replacement therapy (CRRT), peritoneal dialysis and in severe case kidney transplant.
Thermoregulation is a homeostatic mechanism that keeps the body temperature of an organism up to suitable limits independent of external environmental temperature.
Thermoregulation is all about keeping the stability of thermal energy expense in the body.
Humans are endotherms means they maintain their body temperature at suitable limit that is 370C.
Humans have adapted some behavioral and physiological strategies to adjust thermogenesis in cold and hot environment.
ADH stands for anti-diuretic hormone.
BUN stands for Blood nitrogen test.
CRRT stands for Continuous renal replacement theraoy.
DCT stands for Distal convoluted tubule.
ESWL stands for Extracorporeal shock wave lithotripsy. GFR stands for Glomerular filtration rate.
HLA stands for Human leucocytes antigen.
PCNL stands for Percutaneous nephrolithotomy.
PCT stands for Proximal convoluted tubule.
RBC's stands for Red blood cells.
TMAO stands for Trimethylamine oxide.

Tuesday, 3 August 2021

Chapter No.7 : Cell Cycle - Botany And Zoology- For HSC Part 2 (XII) - Science Group

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Chapter No.7
CELL CYCLE
Botany And Zoology
For HSC Part 2 (XII) Science Group

Q.5: Define Meiosis. Explain the various stages of Prophase -I of meiosis.
Ans: MEIOSIS:
Meiosis is a cell division in which one cell divides into four cells and the number of the chromosomes is reduced to half. Meiosis occurs in diploid cells during gametogenesis. Meiosis consists of two successive divisions, Division I and Division II.
Division I is reduction division, during which the chromosomes number (2n) in both daughter cells is reduced to half (n).
Division II is simple mitotic in nature.
Each division passes through four phases, as:

1^st Meiotic Division

Prophase I
Metaphase I
Anaphase I
Telophase I

2^nd Meiotic Division

Prophase II
Metaphase II
Anaphase II
Telophase II

PROPHASE I:
Prophase of first meiotic division is longer in duration and complicated. It passes through five sub-stages.

Leptotene
Zygotene
Pachytene
Diplotene
Diakinesis

Leptotene = (Slender):

This is the first stage of meiosis.
The chromatin material condenses to from thread like structures called chromosomes.
Before meiosis starts, the chromosomes become duplicated which is DNA replication, but the two chromosomes are so close that they look like a thread.
The identical pairs, Maternal and Paternal chromosomes remain unevenly distributed.
The centrioles move to the opposite poles.

Zygotene = (Joining):

The chromosomes shorten and thicken.
The homologous (maternal and paternal) chromosomes attracts each other and start pairing, the process is called SYNAPSIS.
The pairing is very exact and is point to point and gene to gene.
The two synapped chromosomes are called BIVALENTS.

Pachytene = (Thick):

After pairing, the chromosomes become thick and short.
The homologous chromosomes twine around each other and each starts splitting into two sister chromatids by a longitudinal splitting except in the centromere region.
Due to this splitting, the bivalent becomes tetravalent (with four chromatids).

Diplotene = (Double):

The synaptic force of attraction between each bivalent consisting of four chromatids decrease.
The homologous chromosomes start repelling each other but mostly uncoiled i.e. overlapping areas remain contact in one or more points.
This point of contact is called chiasma (Plural: Chiasmata).
The overlapping occurs at non-sister chromatids.
At chiasmata the chromatids breaks. This breakage is accompanied by reunion in such a way that corresponding fragments are interchanged between the two non-homologous chromosomes, this physical change is called crossing over.
Crossing over is significant in heredity.

Diakinesis = (Through movement):

Diakinesis is characterized by the disappearing of the nuclear membrane, nucleolus and completion of spindle apparatus.
The separation of bivalent is completed by the process called terminalization.
The movement of the chiasmata from the centromere towards the ends of the chromosome arms take place like a zipper.
At the end of stage, the two chromatids held together at their ends and the bivalent become more thickened, contracted and prominently visible.