Common Q3~ Flashcards
If too much urea builds up in the blood..
you would get very ill, its toxic to the body
Outline the structure of a kidney.
(tissues and blood vessels)
Tissues making up the outer and inner layers: cortex and medulla.
Renal artery divides to form many tiny, coiled capillaries called glomeruli.
Outline the structure of a kidney.
(nephrons)
Made up of thousands of nephrons. Each begins in the cortex (out and in, out and in). Nephrons join up with the ureter.
Explain how urine is produced. (Blood..)
Blood is filtered in the glomerulus. Only small molecules can pass through the filter, but large molecules and blood cells cannot. Filtrate: water, urea, glucose, ions.
These move into the nephron.
All of the glucose, most of the water and some of the ions are reabsorbed into the blood as the fluid flows through nephron. Blood capillaries come close to the nephron making it easy to move back.
What is the advantage to red blood cells of not having a nucleus?
More space for haemoglobin, and so, able to carry more oxygen. Small enough to squeeze through the smallest capillaries. Biconcave shape provides a large SA and the RBC has a small volume, so diffusion rate of oxygen is great.
Blood glucose concentration too high?
Liver cells break down glycogen to glucose and release it into the blood.
What are the type 1 diabetes symptoms when blood glucose concentration is high?
dry mouth, blurred vision, very thristy, h rate and b rate may increase
What are the type 1 diabetes symptoms when blood glucose concentration is low?
confusion, irrational behaviour, become unconcious
What damage can type 1 diabetes cause?
Over long periods of time, it can damage organs.
What do people with diabetes do regularly in terms of testing?
Habit of checking their blood glucose concentration using a simple sensor.
Can test their urine for glucose using a dipstick. (Should not contain glucose, but if its high..)
What do people with diabetes do regularly in terms of insulin?
Type 1 will take rapid-acting insulin just before or after they eat a meal. Adjust dose accordingly. Long-acting insulin taken daily at the same time, provides background dose of insulin.
What else can people with diabetes do?
Eat little and often. Avoiding large amounts of carbs
Explain why the sex of a child is determined by its father
sex is determined by X and Y chromosomes, females can only provide X chromosome, only males can provide the Y chromosome ;
Outline the role of LH
Causes ovulation.
How do fungus reproduce?
Fungus forms spores, which are tiny groups of cells with a tough, protective outer covering. The spores can be spread by wind or animals, and grow into a new fungus.
Explain how selective breeding/ artificial selection differs form natural selection.
Natural:
>selection pressure comes from the environment
>better adapted individuals survive and reproduce
>produces characteristics suitable for the new environment
>slow
>affects many characteristics
What are the features of gas exchange surfaces?
-thin to allow gases to diffuse across quickly
-close to an efficient transport system to take gases to and from the exchange surface
-large sa, so that a lot of gas can diffuse across them at the same time
-have a good supply of oxygen + blood
How do ferns reproduce?
They reproduce by spores produced on the undersides of their fronds.
Diploid or haploid? gametes
zygote
gametes are haploid, zygote is diploid
State which events occur between pollination and fertilisation.
Pollen grain grows pollen tube which grows down the style into the ovary. Pollen grain secretes enzymes to digest this pathway. The pollen tube grows through the micropyle, into the ovule.
Fertilisation occurs: the male nucleus fuses with the female nucleus, so a zygote is formed.
State which events occur between fertilisation and production of seed.
Sepals, petals and stamens wither and fall off. Ovules start to grow. Each ovule contains a zygote which was formed at fertilisation, and divides by mitosis to form an embryo plant. The ovule is now a seed.
How does a seed remain dormant? (inactive with metabolic reactions taking place very slowly or not at all)
When a seed is formed, the water was drawn out of it. Without water, almost no metabolic reactions can take place inside it. A dormant seed can survive harsh conditions, such as cold and drought which would kill a growing plant.
What conditions does a seed need to germinate?
water, oxygen, warm temperature, light is usually not neccessary (seeds in tropical rainforests will only germinate if there is light)
Compare self-pollination and cross-pollination.
self-pollination have some variation, cross-pollination has more variation (new combos of genes are formed)
