B2.2 Flashcards
How do you calculate surface area to volume ratio of a cube?
(6 x L^2) divided by (L^3)
and then simplified to the lowest ratio
What is the exchange surface in a lung, and how is it adapted?
Alveoli - oxygen into blood, carbon dioxide out of blood
High SA:V ratio by sphere shape and crinkles, thin walls, ventilation allowing air movement and a steep concentration gradient
Why do we need transport systems?
When substances enter our body, it needs to be transported to where it is needed.As we are too big,we cannot rely on diffusion alone to get things around, and we also need to remove toxic / waste products like urea
Why do amoeba not need transport systems
As they are a simple organism,they have a high SA:V ratio so can rely on diffusion alone to get what they need
How does blood get around the body?
Pulmonary artery takes blood to lungs,and they gain oxygen.Pulmonary vein takes blood back to heart.Aorta takes it around the body,and vena cava takes it back to the heart.
What structures are in the heart and which does the blood reach first?
(Left and right) atrium and ventricle
Blood enters the heart into the atrium first,then the ventricle, then out of the heart
What are the 3 blood vessels and their uses?
Arteries - carry blood away from the heart at high pressures
Veins - opposite of arteries
Capillaries - link arteries and veins in tissues and organs, substances move through them
How are capillaries adapted?
1 cell thick walls so things can move through easily
Why do veins have valves?
-They carry blood at low pressure
-So blood might backflow
-Valves prevent this from happening
If you are given a cut open heart,how do you know where the left atrium is?
The left side is where the muscle at the bottom is thicker, and the atrium is on the top half above the ventricle
Name the 4 substances in your blood
Red blood cells
White blood cells
Plasma - most common
Platelets
What do white blood cells do?
They fight disease e,g by making antibodies or engulfing harmful micro organisms
What materials does plasma transport?
Water,digested food,waste,hormones,enzymes,antibodies
Is the Xylem or Phloem made of living cells?
Xylem is made of dead cells
Phloem is made of living cells
What do xylems carry?
Water and other dissolved minerals like potassium
What does the phloem carry?
Photosynthesis related products i.e glucose
How do vascular bundles support a plant?
In the root they are found in the centre and act like an anchor
They are in the outer edge of the stem, providing it strength e.g for in a breeze
They form a network in the leaf that supports softer leaf tissue
What piece of apparatus can be used to measure transpiration in a plant shoot?
Potometer
What is surface area to volume ratio?
The surface of an area per unit volume of an object
What factors affect the rate of transpiration?
Humidity, Air movement (wind), Light intensity, Temperature
Where does blood enter the heart from the body?
The right atrium
What are the benefits of having a double circulatory system?
- Deoxygenated and oxygenated blood does not mix
- Blood is under high pressure as it does not have to travel far
- High pressure means the materials are transported around the body more quickly
