section 1 questions - the nature and variety of organisms

Question 1

what are the 8 basic characterises that all living organisms share?

Answer 1

Movement, Respiration, Sensitivity, Homeostasis, Growth, Reproduction, Excretion, Nutrition

Question 2

name 3 organelles that are found in both animal and plant cells. describe their functions

Answer 2

nucleus - contains genetic material, cell membrane - controls what substances go in and out, cytoplasm - where chemical reactions happen. mitochondria - aerobic respiration, ribosomes - protein synthesis

Question 3

what is a tissue?

Answer 3

a group of similar cells that work together to carry out a particular function

Question 4

what is an organ and an organ system?

Answer 4

group of different tissues that work together to perform a function. organs work together to form organ systems

Question 5

what is cell differentiation?

Answer 5

the process in which cell change to become specialised for its Job

Question 6

give 2 ways that embryonic stem cells could be used to cure disease?

Answer 6

1. can replace faulty sells in sick people - insulin-producing cells for people with diabetes
2. differentiated into specialised cells to use in research

Question 7

what are plant cell walls made of?

Answer 7

cellulose

Question 8

what do plants store carbohydrates as?

Answer 8

sucrose or starch

Question 9

how do most animals store carbohydrates

Answer 9

glycogen

Question 10

what is saprotrophic nutrition

Answer 10

excreting extracellular enzymes into the area outside their body to dissolve their food so they can then absorb the nutrients

Question 11

what is the body of a fungi called? what is it made up of?

Answer 11

mycelium, hyphae (threadlike structures that contain lots of nuclei)

Question 12

2 examples of protoctists

Answer 12

chlorella and omoeba

Question 13

3 features of viruses

Answer 13

only reproduce inside living cells, have a protein coat around genetic material, particles, infect all types of living organisms

Question 14

what are pathogens

Answer 14

organisms that cause disease - some fungi, protoctists, bacteria and viruses

Question 15

what is an example of a protoctist that causes disease

Answer 15

plasmodium causes malaria

Question 16

what does pneumococcus cause?

Answer 16

pneumonia

Question 17

what is a catalyst?

Answer 17

a substance which increases the speed of a reaction without being changed or use up

Question 18

what is an enzyme

Answer 18

biological catalyst

Question 19

what does it mean by ‘denatured’

Answer 19

bonds holding the enzyme together break which changes the shape of the enzymes active site so the substrate won’t fir anymore.

Question 20

what is the effect of temperature of enzymes?

Answer 20

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

Question 21

describe an experiment to show how temperature can effect enzyme activity

Answer 21

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

Question 22

what is diffusion

Answer 22

the net movement of particles from an area of higher concentration to an area of lower concentration - passive prosess

Question 23

what is osmosis

Answer 23

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

Question 24

what can be used to investigate osmosis in a living and a non-living system

Answer 24

potato cylinders (living), risking tubing (non-living)

Question 25

what is active transport

Answer 25

the movement of particles against the concentration using energy from respiration

Question 26

how is active transports different from diffusion

Answer 26

it is against the concentration and is an active process so requires energy

Question 27

what are 4 factors that affect the movement of substances

Answer 27

SA:V, distance, temperature, concentration gradient