biology

Question 1

what is a cell and what does it do

Answer 1

a cell is a basic block of life it take in raw materials can converts them into molecules which are used to fulfil different functions

Question 2

protoplasm

Answer 2

protoplasm is the living matter of the life and is made of the nucleus , cytoplasm and the cell membrane

Question 3

cytoplasm

Answer 3

the cytoplasm is a jellylike substance it is the site most of the chemical reactions take place it contains specialized structures known as organelles

Question 3

the cell membrane

Answer 3

surround the cytoplasm it is made out proteins and lipid and it is partially permeable so allowing smaller soluble substance to diffuse through the membrane therefore the function is to control the movement of substances going in and out of the cell

Question 4

nucleus

Answer 4

the nucleus controls all the activities that occur in the cell and is essential for cell division it consist of a chromatin and a nuclear membrane

Question 5

the chromatin

Answer 5

chromatin a long tread like structure that contains a compound known as deoxyribonucleic acid DNA which contain hereditary information and during cell division the chromatin condenses into a short thick rod shape structure known as chromosomes

Question 6

nuclear membrane

Answer 6

it separates the content of the nucleus from the rest of the cell

Question 7

rer rough endoplasmic reticulum

Answer 7

the rough endoplasmic reticulum is a network of flattened spaces lined with a membrane
the outer surface is continuous with a nuclear envelope
the surface of the rough endoplasmic reticulum has ribosomes attached to it therefore making it rough
the function of the rough endoplasmic reticulum is to transport proteins made by the ribosome into the Golgi body

Question 8

ribosome

Answer 8

the ribosome are small circular structures that can either be seen lying freely around the cytoplasm or attached to the surface of the rough endoplasmic reticulum
its function is the synthesis of proteins

Question 9

SER smooth endoplasmic reticulum

Answer 9

the smooth endoplasmic reticulum is more tubular than the rough endoplasmic reticulum it does have any ribosomes attached to the surface and therefore smooth its function is to synthesis substances like steroids and lipase and is involved in neutralization

Question 10

Golgi body

Answer 10

the Golgi body consist of flatten spaces surrounded by a membrane it function is to modify substances made by the ser and rer and is then stored and packaged as vesicles and secretes out of the cell through the cell membrane

Question 11

mitochondrion

Answer 11

it is the power house of the cell it a oval or sausage like structure that helps to release energy for the cell through aerobic respiration by oxidizing with food molecules to release energy for cellular activities

Question 12

the process of substance being transported from the endoplasmic reticulum to the the Golgi body and out the cell

Answer 12

the vesicles containing substances from the endoplasmic reticulum is pinched off the endoplasmic reticulum and the vesicles fused into the Golgi body which is then modified and the secreted vesicles is then pinched out the Golgi body and the secretory vesicles then fuse with the cell membrane and the content is release out of the cell

Question 13

chloroplast

Answer 13

chloroplast is a oval shape structure and contains a pigment known as chlorophyll which helps to absorb sunlight needed for photosynthesis

Question 14

vacuole

Answer 14

the vacuole is a fluid filled space that stored substances within the cell and is enclosed by a partially permeable membrane
the animal vacuole are tiny and numerous and stores substances such as water and food substance and they temporarily exist
while the plant vacuole is large and central vacuoles and carries substances such as amino acids sugars and mineral salts

Question 15

cell wall

Answer 15

a cell wall surrounds the cell membrane it is fully permeable and it is made out of cellulose it gives the plant a fixed shape and prevent the plant from injuries

Question 16

muscle cell

Answer 16

muscle cell contain numerous mitochondria to provide energy for muscles contractions and it has contractile protein fibers for contraction and relaxation to bring about movement
it has numerous nucleus for cell division

Question 17

the root hair cell

Answer 17

the root hair cell has a narrow and long extension to increase the surface area to volume ratio to maximize the rate of absorption of water and mineral salts
the vacuole maintains a lower water potential this ensure water is able to diffuse through the membrane through osmosis

Question 18

additional stem cell

Answer 18

scientist can take them transform them into different organs and is transplanted into a person

Question 19

what is diffusion

Answer 19

diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient until equilibrium is reached

Question 20

how is concentration gradient related to diffusion

Answer 20

the motion of particles are random and the particle diffuse down the concentration gradient which the steep the concentration gradient the greater the rate of diffusion

Question 21

diffusion across a membrane

Answer 21

when both substance can pass through the partially permeable membrane diffusion also occurs

Question 22

what affects the rate of diffusion

Answer 22

the rate of diffusion is affected by the temperature the steepest of the concentration gradient and the diffusion distance
nature of solvent and mass of solute

Question 23

why are the walls of the blood capillaries one cell thick

Answer 23

as this is to decrease the diffusion distance and this increases the rate of diffusion ensuring maximum efficiency of the exchange of substances

Question 24

how does oxygen get from the leaves to the root

Answer 24

the oxygen diffuses down a concentration gradient from a higher concentration in the roots to a lower concentration in the hair root cell

Question 25

why do the small intestine have folded membranes

Answer 25

as this is to increase the surface area to volume ratio and increase the rate of diffusion ensuring maximum efficiency of nutrient flowing into the capillaries

Question 26

why does the viscosity of the solvent and the mass of the solute matter

Answer 26

as the went a solvent is more viscous which means its dense and thicker this would decrease the rate of diffusion as the particles have a difficult time and when the solute is greater in mass this means the particles are heavier which decreases the rate of diffusion

Question 27

what is osmosis

Answer 27

osmosis is the net movement of water molecules from a greater water potential to a lower water potential through a partially permeable membrane

Question 28

what happens if in a dialysis tubing with 20 % sucrose solution surrounded by distilled water

Answer 28

through osmosis the water has a higher water potential than the sucrose solution so the water moves down a water potential gradient through the partially permeable membrane and the net movement only stops when equilibrium is reached

Question 29

how is water potential gradient related to osmosis

Answer 29

as the water molecules are in a constant motion and the water molecules move down a concentration gradient

Question 30

factors that affect osmosis

Answer 30

surface area to volume ratio, the distance of water molecules needed to move and water potential gradient

Question 31

what happens to plant cell in higher water potential solution

Answer 31

so the water has a greater water potential than the cell sap of the plant so water enter through osmosis and plant cells expands and become turgid and it does not burst as there is a cell wall that ensures the fixed shape of the plant

Question 32

a red blood cell in distilled water

Answer 32

there is greater water potential in the distilled water than the red blood cell so water enters the red blood cell through osmosis and the red blood cell expands and burst

Question 33

plant cell in a lower water potential solution

Answer 33

the cell sap in the plant has a greater water potential than the lower water potential solution so water leaves the cell sap through osmosis and plant cell becomes flaccid and the cytoplasm shrinks away from the cell wall and it become plasmolyzed

Question 34

red blood cell in a sugar solution

Answer 34

the red blood cell has a higher water potential than the sugar solution so water leaves the red blood cell through osmosis and the red blood cell shrinks and become crenated and becomes spiky in shape

Question 35

how does turgor play a role in plants

Answer 35

as it helps keep the plant stay upright an firm due to it being turgid while if the cell was flaccid the plant would start to wilt

Question 36

what is active transport

Answer 36

active transport is used of cellular energy when particles of substance move across a membrane against a concentration gradient from a lower concentration to a high concentration

Question 37

is active transport used to absorb mineral salts

Answer 37

yes active transport is used to absorb dissolved mineral salt when there is a higher concentration in the root than the soil so it goes a against the concentration gradient enquiring all of energy through respiration

Question 38

why do we eat and what are 3 main nutrient

Answer 38

as it provides the body with energy and materials needed for the body and the 3 main nutrients are the carbohydrates , proteins and fats

Question 39

why is water needed

Answer 39

as water makes up 70% of our body it is a greater solvent for many chemical reactions it keeps cells firm and turgid help transport mineral salts in plants it help to regulate body temperature and transport dissolved substances around the body

Question 40

formula for carbohydrates

Answer 40

carbohydrates contains of 3 elements such a carbon , oxygen and hydrogen the ratio for carbohydrates is always 2 is to 1

Question 41

what are the different groups of carbohydrates classified as

Answer 41

they are monosaccharide such as glucose and fructose disaccharide such as maltose and sucrose and polysaccharide which include starch, cellulose and glycogen

Question 42

properties of single and double and complex sugar

Answer 42

basic unit of carbohydrates glucose is found in both animal and the plants while fructose is only found in plants rarely in human maltose in found in malt sugars formed by 2 glucose molecules sucrose is found in fruits or cane sugars formed by one fructose and a glucose molecule complex sugars made of many glucose molecules joined together in different ways forming starch which is a form of storage in plant cellulose which is a dietary fiber found in cell walls and glycogen a storage of glucose in liver and muscles in mammals

Question 43

what is benedicts test for and what happens

Answer 43

the benedicts test is used to test for the presence of reducing sugars which is all the mono and disaccharides except for sucrose brick red means there is a large amount of reducing sugars precipitate and if there is a orange precipitate there is a moderate amount of reducing sugars and if there is yellowish green precipitate there a small amount of reducing sugar and if the solution remains blue there is not presence of reducing sugars

Question 44

how to conduct a benedicts test

Answer 44

add 2cm2 of the food sample into a test tube and add to 2cm2 of benedicts solution into the same test tube and shake well and place the test tube in a beaker of boiling water for 5 minutes and obverse the precipitate formed

Question 45

what happens during vigorous activities

Answer 45

during vigorous activities the muscles contract vigorously and aerobic respiration in muscles cells start to increase and the heart rate increase to supply more oxygen and the breathing rate increases to obtain more oxygen however when aerobic respiration is not able to meet the increased energy demands anaerobic respiration takes place to meet the energy demands lactic acid accumulates in the muscles cell resulting in oxygen debt

Question 46

what is oxygen debt

Answer 46

oxygen is the amount of oxygen needed to remove lactic acid

Question 47

why are our heart rate and breathing rate still fast after a run

Answer 47

as to make sure the oxygen uptake is higher enough to replenish oxygen debt

Question 47

how is lactic acid removed

Answer 47

as there is lactic acid accumulated in the muscles cell which in high levels can be toxic for the body and result in fatigue or cramps so lactic acid from the cell are transported to the liver to break the lactic acid into harmless forms so the heart rate increases to supply more oxygen to the liver at a faster rate and transport the lactic acid from cells to the liver and breathing rate increases to obtain more oxygen supplied to the liver

Question 48

wat does potassium hydroxide do

Answer 48

remove co2

Question 49

lime water in presence of co2

Answer 49

the limewater turns cloudy

Question 50

hydrogencarbonate indicator when co2 present

Answer 50

since co2 is slightly acidic it will turn the hydrogencarbonate indicator from red to yellow

Question 51

why is there a layer of oil in anaerobic respiration

Answer 51

to prevent oxygen from atmosphere to interfere with the experiment preventing yeast to respire aerobically

Question 52

why boil glucose in a test for anaerobic respiration

Answer 52

to remove oxygen and carbon dioxide in glucose so carbon dioxide does not interfere with the test of anaerobic respiration

Question 53

what is observed in limewater in an anaerobic respiration test

Answer 53

cloudy as when yeast anaerobically respire they produce carbon dioxide turning it cloudy

Question 54

flow of air in human

Answer 54

nasal passage pharynx , larynx , trachea bronchi bronchioles and alveoli [ air sacs]

Question 55

nasal passage

Answer 55

air enter through the 2 external nostrils the walls of the nasal passage are surrounded by a fringe of hair and the nostril lead in to 2 nasal passage are lined with a moist mucus membrane the fringe of hair and the layer of mucous is meant trapped all the dust and foreign particles bacteria and the mucous membrane has small sensory cells that detect harmful chemicals and in the nasal passage it is moisten and warm

Question 56

pharynx and larynx

Answer 56

air from the nasal passage and into the pharynx and from pharynx enters the larynx and air enters through the openings of the trachea

Question 57

bronchi and bronchioles

Answer 57

the trachea divides into 2 bronchi and each bronchus carries air into each lungs the structure of the bronchus is similar to that of a trachea and its a c- shaped cartilage and the bronchus branches out repeatedly to give rises to numerous bronchioles which are fine tube and the end of the bronchioles have a cluster air sac or a alveoli

Question 57

the trachea

Answer 57

it has a c-shaped cartilage that helps keep the lumen open the membrane next to the lumen is the trachea epithelium the epithelium consist of gland cells which secrete mucus to trap dust and bacteria and ciliate cells that are hair like structure which is cilia found on the surface that help sweep up mucus dust trapped particles up to the larynx and to the pharynx

Question 58

alveoli

Answer 58

gas exchanges takes place at the walls of the alveoli and there is numerous number of alveoli found the lung to increase surface area to volume ratio to increase rate of diffusion and maximize the rate of gas exchange

Question 59

how does the lung adapt to efficient gas exchange

Answer 59

there are numerous alveoli found in the lung as this is to increase the surface area to volume ratio to increase the rate of diffusion and maximizing the rate of gas exchange making it efficient the walls of the alveoli and the blood capillaries are one cell thick only as this is to ensure the diffusion distance between the blood capillaries and the alveoli is short and this would help increase the rate of diffusion and increases rate of gas exchange there is a thin film of moisture that covers the inner wall of alveolus this helps to dissolve the oxygen for an easier diffusion across the alveoli walls the walls of the alveolus is richly supplied with blood capillaries this allows blood rich in oxygen to quickly be away from the alveolus and blood rich is carbon dioxide to the alveolus quickly this ensures a steep concentration gradient to increase the rate of diffusion of carbon dioxide entering the alveolus and oxygen leaving the alveolus into the walls

Question 60

how does gas exchange occur in the alveoli

Answer 60

gas exchange occurs through diffusion where the concentration of oxygen in the alveolar air is lower than the atmospheric air and the concentration of carbon dioxide in the alveolar air is greater than the atmospheric air this therefore creates a concentration gradient from both carbon dioxide and oxygen between the alveolus air and the blood and gas exchange occurs

Question 61

breathing mechanism dirt laa inhalation

Answer 61

during inspiration the diaphragm contracts and the diaphragm muscles flatten downward the internal intercoastal muscles relax and the external intercoastal muscles contract this cause the ribs to move upward and outwards and the thoracic cavity increases in volume and the lungs expand and the air pressure in the lung decreases the volume increases so the atmospheric pressure is greater than the air pressure in the lungs causing air to be force in to the lung

Question 62

describe the process of oxygen and carbon dioxide entering and leaving

Answer 62

so oxygen from the alveoli is dissolved into the thin film of moisture and then it diffuses through the walls of the alveoli and the the walls of the blood capillary and bind with the haemoglobin to form oxyhaemoglobin and is transported to the pulmonary veins and and the carbon dioxide in the blood diffuses through the walls of the blood capillaries and the walls of the alveoli where it enters the alveolar air and is transported out of the body

Question 63

thoracic chest cavity

Answer 63

the chest wall are supported by the rib cage which the 2 sets of muscles found in the thoracic chest cavity which is the internal intercoastal muscles and the external intercoastal muscles and are antagonistic in action the thorax is separated from the abdomen with a domed shaped diaphragm made out muscles and elastic tissue when the diaphragm contract the diaphragm muscles flatten downwards and when the diaphragm relax the diaphragm muscles arched upwardsn

Question 64

exhalation dirtlaa

Answer 64

during expiration the diaphragm relax the diaphragm muscles aches downward and the internal intercoastal muscles contract and the external intercoastal muscles relax and the rib cage moves downward and inwards and the volume of the thoracic cavity decreases so the lungs are compressed and the air pressure in the lung increases as the volume decreases and the air pressure in the lungs to be greater than the atmospheric pressure causing air to be forced out of the lungs

Question 65

nicotine

Answer 65

nicotine causes addiction and this increases the release of a hormone called adrenaline which this increase the heart rate and the blood pressure narrowing the arteries and this could increase the risk of blood clot and increase the risk of heart disease such as coronary heart disease

Question 66

Tar

Answer 66

tar contains carcinogenic which is cancer causing which results in uncontrollable cell division it paralyzed the cilia lining the air passage so dust trapped mucus is unable to be removed in the lung so the lungs compensates by secreting more mucus which traps more dust and bacteria which can result in lung infection and increases the risk of chronic bronchitis and emphysema and reduces the efficiency of gas exchange as tar can coat the inner walls of the alveoli and decrease the surface area and reducing the rate of diffusion and decreasing efficiency of gas exchange as it reduces the available for the exchange of gases to take place

Question 66

carbon monoxide

Answer 66

carbon monoxide decrease the ability of oxygen being able to bind with the haemoglobin as it bind with carbon monoxide irreversibly with haemoglobin to form carboxyhaemoglobin and this prevents oxygen to bind with haemoglobin this decrease the supply of oxygen to vital organs such as the brain and the heart this can result in a breathlessness and organ failure and increase the rate of which fats are deposited into the arterial walls which increases the risk of atherosclerosis or coronary heart disease

Question 67

irritant

Answer 67

irritants such as hydrogen cyanide formaldehyde which their paralyze the cilia lining the air passage and the dust trapped mucus cannot be removed and the lungs compensate by secreting more mucus from the gland cells and this increases the amount of bacteria and dust trapped and increase the risk of chronic bronchitis and emphysema

Question 67

chronic bronchitis