biology igcse Flashcards
what are the characteristics of living organisms
MRS GREN
movement
respiration
sensitivity
growth
reproduction
excretion
nutrition
what is the chemical equation of cellular respiration
glucose+oxygen —> carbon dioxide + water
define movement
the change of place or position caused by an organism
define respiration
the chemical reaction in cells that break down to release energy for metabolism
define sensitivity
the ability to detect and respond to changed of the environment
define growth
the permanent increase in size and dry mass of a living organism
define reproduction
the process of making the same kind of organism
define excretion
the removal of waste products for metabolic processes
define nutrition
taking in materials for energy, growth and development
define species
the group of similar living organisms that can breed with one another to produce a fertile
what are the two levels of classification in the binomial system
genus + species
A student defined respiration as being the same as breathing. Are they correct? Provide a reason to support your answer.
Breathing and respiration are two completely different things but interrelated body processes that assist body organs to function properly
Humans breathe but bacteria do not. Is it correct to state that bacteria are alive? What makes you think that?
Bacteria is not considered a living organism as it does not share all the characteristics of living organisms
What is the energy released in cellular respiration used for?
You need energy to grow, move around, to excrete cell division
Why is it important to say that energy is released, not produced.
As energy cannot be created nor destroyed, only transferred
Why does an increase in the number of cells cause growth?
the increase in the number of cells increase the volume and size of an organism
Why does the amount of dry mass in an organism cause growth?
Dry mass is made up of organic molecules when there is more organic molecules, the dry mass increases
what are the two types of reproduction
sexual and asexual
How do the two forms of reproduction differ from each other?
Sexual is where offsprings are a result of 2 different gametes fusing together.
Asexual is where offspring are from the same parent
What is metabolism?
Metabolism is the term used for chemical reactions that go on inside an organism’s body.
How is metabolism linked to excretion?
Metabolic processes toxic products and it is removed from the body through excretion.
This image shows a cow producing faeces. Is this an example of excretion? What makes you think that?
No, as faeces is not excretion, it is undigested food, Excretion as the removal of the waste products of metabolism and substances in excess of requirements.
What is the purpose of nutrition?
To give the substances as it needs to release energy
What is the difference between a nutrient and nutrition?
Nutrient is a substance you consume and nutrition is the process of taking in and using those substances.
How do plants obtain their nutrients?
Photosynthesis
How do animals obtain their nutrients?
Consumption of organic matter
what are they three ways that a plant cells differs to animal cell
- cell wall
-permanent vacuole - chloroplast
what is the function of a nucleus
contains DNA and controls the activity of the cell
what is the function of a mitochondrion
carries out respiration
what is the function of a ribosome
to make protein
what is the function of a cell membrane
controls the movement of the cell of what goes in and out
what is the function of a cytoplasm
biochemical reactions occur here
what is the function of a vacuole
it contains water and ions
what is the function of a root hair cell and explain
to absorb water and inorganic nutrients
- the long extensions increase the surface area of the cell enabling it to absorb water and nutrients more efficiently
what is the function of a ciliated cell and explain
the movement of mucus int he trachea and bronchi
- moving mucus
- hair like projection
what is the function of a palisade mesophyll cell and explain
carries out photosynthesis
- lots of mitochondria and a large surface area to maximise the absorption of light
what is the function of a red blood cell and explain
to transport oxygen
- contains haemoglobin to bind with oxygen
- no nucleus for more space
what is the function of a sperm cell and explain
reproduction
- tails to swim
- lots of mitochondria
- has enzymes in the acrosome
what is the function of a ovum and explain
reproduction
- large cytoplasm with yolk as energy store
- outer layer prevents more than one sperm entering
- fuses witha sperm to form a zygote
