Nature And Variety Of Organisms Flashcards
(24 cards)
What are the characteristics of living organisms?
- they need nutrition
- they respire
- they excrete their waste
- they move
- they can control their internal conditions
- they reproduce
- they can grow and develop
What is a nucleus?
An organelle that contain genetic material that controls the cells activities.
What is a cell membrane?
Controls what goes in and out of the cell
What are mitochondria?
Small organelles where most of the reactions for aerobic respiration take place
What are ribosomes?
Small organelles where protein is made in a cell
What is cytoplasm?
A gel-like substance where most of the cells chemical reactions happen. It contains enzymes which control these reactions.
What is a vacuole?
A large organelle that contains cell sap ( a weak solution of sugars and salts). Helps support the cell
What is a cell wall?
A structure made of cellulose, which surrounds the cells membrane. It supports and strengthens the cell
What are chloroplasts?
Where photosynthesis occurs, which makes food for the plant. Chloroplasts contains a green substance called chlorophyll which is used in photosynthesis.
What is cell differentiation?
Is the process by which cell changes to become specialised for it’d job. As the cells change they develop different organelles that turn into different types of cells. This allows them to carry out specific functions.
What are undifferentiated cells called?
Stem cells
Where are stem cells found?
I’m early human embryos and bone marrow
What are the risks of using stem cells in medicine?
Stem cells grown in a lab may become contaminated and pass it onto the patient making them sicker.
Why are some people against stem cell research?
- feel that human embryos shouldn’t be used for experiments since each one is potential human life
- feel that scientists should be trying to find other sources of stem cells so people could be helped without embryos
What type of organism are plant,animals and fungi?
Eukaryotic
Features of plants:
-multicellular
-have chloroplasts, which mean they can photosynthesise
-their cells have cell walls which are made of cellulose
-plants store carbohydrates as sucrose or starch
E.g. flowering plants like : cereals (e.g maize), herbaceous legumes (e.g peas and beans)
Features of animals:
-multicellular
-most have some kind of nervous coordination. This means they can responds rapidly to the changes in their environment
-can usually move around from one place to another
-often store carbohydrates in the form of glycogen
E.g. mammals (e.g human), insects (e.g houseflies and mosquitoes)
Features of fungi:
-some are single celled
-others have a body called mycelium, which is made up of hyphae (thread like structures)
-can’t photosynthesise
-most feed my saprophytic nutrition
-store carbohydrate as glycogen
E.g. yeast, mucor
What is saprophytic nutrition?
They secrete extracellular enzymes into the area outside their body to dissolve their food so they can then absorb nutrients
Protoctists
-single celled & microscopic
-some have chloroplasts
E.g.chlorella (plant cell like), amoeba (animal cell like)-lives in pond water
Bacteria
-single celled & microscopic
-don’t have a nucleus
-have a circular chromosome of DNA
-some can photosynthesise
-most bacteria feed of other organisms (living & dead)
E.g. lactobacillus bulgaricus, pneumococcus
Viruses
- particles rather than cells
- reproduce in living cells
- infect all types of living organisms
- come in different shapes & sizes
- don’t have a cellular structure- they have a protein coat around some genetic material
What is a catalyst?
A substance which increases the speed of a reaction, without busing changed or used up in the reaction
What are metabolic reactions?
Enzymes speeding up useful chemical reactions in the body
