b4 organising animals and plants

Question 1

what is the heart

Answer 1

a organ that pump blood around the body made from cardiac muscle tissue which is supplied with oxygen by the coronary artery

Question 2

what are the parts of the heart

Answer 2

aorta:carries oxygenated bloof around the body
pulmonary vein:brings oxygen around the body
left ventricle:pumps blood around the body
right ventricle:pumps blood to the lungs
vena cava:brings deoxygenated blood into the heart
pulmonary artery:takes deoxygenated blood to the lungs

Question 3

why is the heart a double circulatory system

Answer 3

blood passes through the heart twice for every circuit around the body

Question 4

what are the 4 components of blood

Answer 4

red blood cells:bind to oxygen and transport it around the body
plasma:transport substances and blood around the body
platelets:form blood clots to create barriers to infection
white blood cells:part of the immune system to defend the body against pathogens

Question 5

what is coronary heart disease caused by

Answer 5

build up of fatty material in the coronary artery making them narrow and reducing blood flow.stents can be used to keep the coronary artery open

Question 6

what are the 3 blood vessels

Answer 6

artery:carries blood away from the heart at high pressure the artery has thick muscular walls that can stretch and withstand high pressure
vein:carries blood to the heart at low pressure they have valves to stop blood flowing the wrong way has thin walls
capillary:carries blood to tissues and cells and connects arteries and veins one cell thick short diffusion range for substances to move between the blood and the tissues

Question 7

what are the parts of a leave

Answer 7

waxy cuticle
upper epidermis
palisade mesophyll
spongy mesophyll
stomata
guard cells

Question 8

what is transpiration

Answer 8

water is lost through the stomata by evaporation this pulls water up from the xylem

Question 9

what are xylem and phloem vessels

Answer 9

xylem: one way transport only water and minerals made of dead cells joined together with no end walls between them and thick walls stiffened with lignin
phloem:transports water and disssolved sugars cells have end walla with small holes to allow substances to flow through and substances transported in both directions

Question 10

what is translocation

Answer 10

movemnt of dissolved sugars from the leaves to the rest of the plant through the phloem this allows for repiration growth and glucose storage

Question 11

what factors affect transpiration

Answer 11

temperature:higher temperature increases the rate of transpiration because water evaporated faster in higher temperatures
humidity:lower humidity increases the rate of tranpiration because the drier the air the steeper the concentration gradient of water molecules between the air and leaf
wind speed:more wind increases the rate of transpiration because winf removes the water vapour quickly maintaining a steeper concentration gradient
light intensity:higher light intensity increases the rate of transpiration because the stomata opens wider to let more carbon dioxide into the leaf for photosynthesis