Biology- Organisation of animals and plants

Flashcards

Give two ways the lungs are adapted for efficient gas exchange

Large SA:V ratio , many alveoli

Where does gas exchange happen in the breathing system

The Alveoli

name the cells that control the size of the stomata

guard cells

One disadvantage of a plant having a large number of stomata per mm2 of each leaf

is increased water loss through transpiration, which can lead to drought stress.

What is one enviromental condition where a large number of stomata per mm2 on each leaf would be a disadvantage

can lead to excessive water loss during dry conditions, detrimental to the plants survival

Explain how the spongy mesophyll is adapted for its function

The spongy mesophyll contains loosely packed cells with many air spaces that facilitate gas exchange and improve carbon dioxide diffusion for photosynthesis. So the gases can diffuse through the leaf to the palisade layer

One way the xylem is adapted for its function

has no end cells , a continuous , hollow tube that transports water and minerals from the roots to the leaves efficiently.

where is the pacemaker found?

right atrium

Describe how an increase in glucose concentration in the guard cells causes the stoma to open

water enters the cells via osmosis, causing them to become turgid. This results in the opening of the stoma, allowing gas exchange to occur.

what is meant by a double circulatory system

means blood passes through the heart twice in one full body circuit.

• right ventricle pumps blood to the lungs and then left ventricle pumps blood to the body

which blood vessel carries deoxygenated blood

pulmonary artery away from the heart to the lungs for oxygenation.

Three structural differences between a vein and an artery

Veins have thinner walls and larger lumens, while arteries have thicker walls and carry blood under higher pressure. Arteries do not have valves, while veins do. Arteries have elastic walls, valves have less muscle and elastic tissue

Why do veins have valves and arteries don’t

Veins have valves to prevent backflow of blood as it returns to the heart under lower pressure, while arteries do not require valves because they carry oxygenated blood away from the heart at higher pressure.

Function of the epidermis in plants

Acts as a barrier against physical damage, pathogens, and water loss. and allows diffusion of gases through the leaf.

function of the Phloem

transport of nutrients and sugars produced by photosynthesis throughout the plant

function of the spongy mesophyll

facilitates gas exchange and contains air spaces for carbon dioxide diffusion during photosynthesis.

in which part of a cell does aerobic respiration take place

mitochondria

Explain how the structure of an artery is related to its function

Arteries have thick, elastic walls to withstand high pressure from blood pumped by the heart, allowing for efficient transport of oxygen-rich blood throughout the body.

Function of an artery

Arteries carry blood away from the heart at high pressure. Most arteries carry oxygenated blood (except the pulmonary artery, which carries deoxygenated blood to the lungs).

Main type of tissue in the heart wall

The main tissue in the heart wall is cardiac muscle tissue, which allows the heart to contract regularly and forcefully to pump blood around the body.

In which blood vessel is a stent placed

coronary artery

How can a stent prevent a heart attack

by keeping the coronary arteries open, allowing oxygenated blood to reach the heart muscle.

Steps of how a stent works

• A stent is a small metal mesh tube.

• It's inserted into the narrowed coronary artery.

• The stent widens the artery and holds it open.

• This restores proper blood flow to the heart muscle.

• As a result, it reduces the risk of a heart attack.

What is a potometer used to measure?

the water uptake of a plant through transpiration