section 1 questions - the nature and variety of organisms Flashcards
what are the 8 basic characterises that all living organisms share?
Movement, Respiration, Sensitivity, Homeostasis, Growth, Reproduction, Excretion, Nutrition
name 3 organelles that are found in both animal and plant cells. describe their functions
nucleus - contains genetic material, cell membrane - controls what substances go in and out, cytoplasm - where chemical reactions happen. mitochondria - aerobic respiration, ribosomes - protein synthesis
what is a tissue?
a group of similar cells that work together to carry out a particular function
what is an organ and an organ system?
group of different tissues that work together to perform a function. organs work together to form organ systems
what is cell differentiation?
the process in which cell change to become specialised for its Job
give 2 ways that embryonic stem cells could be used to cure disease?
- can replace faulty sells in sick people - insulin-producing cells for people with diabetes
- differentiated into specialised cells to use in research
what are plant cell walls made of?
cellulose
what do plants store carbohydrates as?
sucrose or starch
how do most animals store carbohydrates
glycogen
what is saprotrophic nutrition
excreting extracellular enzymes into the area outside their body to dissolve their food so they can then absorb the nutrients
what is the body of a fungi called? what is it made up of?
mycelium, hyphae (threadlike structures that contain lots of nuclei)
2 examples of protoctists
chlorella and omoeba
3 features of viruses
only reproduce inside living cells, have a protein coat around genetic material, particles, infect all types of living organisms
what are pathogens
organisms that cause disease - some fungi, protoctists, bacteria and viruses
what is an example of a protoctist that causes disease
plasmodium causes malaria
what does pneumococcus cause?
pneumonia
what is a catalyst?
a substance which increases the speed of a reaction without being changed or use up
what is an enzyme
biological catalyst
what does it mean by ‘denatured’
bonds holding the enzyme together break which changes the shape of the enzymes active site so the substrate won’t fir anymore.
what is the effect of temperature of enzymes?
higher temperature increases the temperature. there is more kenetic energy so more collisions causing more enzyme-substate complexes to be formed. when it gets to hot then the enzyme is denatures
describe an experiment to show how temperature can effect enzyme activity
how fast a substrate disappears: use the enzyme amylase which breaks down starch to maltose.
C = the temperature of the water bath heating the amylase and starch solution
O = use the same starch solution at each temperature
R = repeat 3 times
M = drop a sample of mixture into the tiles every 10 seconds until the iodine remains orange/ brown because starch is no longer present
M = repeat at different temperatures to see how it affects the time for the starch to be broken down
S = the same volume of starch solution and amylase
S = the same pH
what is diffusion
the net movement of particles from an area of higher concentration to an area of lower concentration - passive prosess
what is osmosis
the net movements of water molecules across a partially permeable membrane from a region of higher warter consentration to an area of lower water concentration
what can be used to investigate osmosis in a living and a non-living system
potato cylinders (living), risking tubing (non-living)
what is active transport
the movement of particles against the concentration using energy from respiration
how is active transports different from diffusion
it is against the concentration and is an active process so requires energy
what are 4 factors that affect the movement of substances
SA:V, distance, temperature, concentration gradient
