topic 1: nature and variety in living organisms

Question 1

mrs gren

Answer 1

movement
reproduction
sensitivity

growth
respiration
excretion
nutrition

Question 2

prokaryotic

Answer 2

smaller and simpler e.g bacteria

Question 3

eukaryotic

Answer 3

complex, including all animal and plant cells

Question 4

organelles

Answer 4

tiny structures within cells

Question 5

organelles found in a typical animal cell

Answer 5

cell membrane
nucleus
cytoplasm
ribosomes
mitochondria

Question 6

additional organelles found in a typical plant cell

Answer 6

vacuole
chloroplast
cell wall

Question 7

cell membrane

Answer 7

forms the outer surface of the cell and controls the substances that goes in and out

Question 8

nucleus

Answer 8

organelle which contains the genetic material that controls the cells activities

Question 9

cytoplasm

Answer 9

a gel like substance where chemical reactions happen. contains enzymes that control said reactions

Question 10

ribosomes

Answer 10

small organelles where proteins are made in the cell

Question 11

mitochondria

Answer 11

small organelles where most of the reactions for aerobic respiration take place

Question 12

tissue

Answer 12

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

Question 13

organ

Answer 13

a group of tissues that work together to perform a function

Question 14

what does it mean when cells are specialised

Answer 14

they have a particular structure that can carry out the specific function

Question 15

cell differentiation

Answer 15

where a cell changes to become specialised for its job, developing different organelles for carrying out specific functions

Question 16

stem cells

Answer 16

undifferentiated cells that can differentiate into different types of cell depending on the instructions given

found in either embryos/bone marrow

Question 17

usage of stem cells (embryonic + bone marrow)

Answer 17

adult stem cells (bone marrow) can be used to replace faulty blood cells in the patient who recieves them

embryonic stem cells can replace the faulty cells in sick people, e.g insulin producing cells for people with diabetes and nerve cells for people with paralysis, etc.

Question 18

problem with stem cells

Answer 18

body may reject the stem cell

viruses could be passed on from the lab

ethical issues surrounding embryos and how its human life

Question 19

plants

Answer 19

multicellular
contains chloroplast so they photosynthesise
stores carbohydrates as sucrose/starch
cell wall made of cellulose

Question 20

animals

Answer 20

multicellular
have a nervous coordination meaning that they are able to respond rapidly to their environment
able to move
stores carbohydrates in the form of glycogen

Question 21

fungi

Answer 21

some are single celled
others have a mycelium made up of hyphae (thread like structures) that contain a multitude of nuclei
cell walls made of chitin
feed by saprotrophic nutrition
store carbohydrates as glycogen

Question 22

protoctists

Answer 22

single celled
very very tiny
some have chloroplasts and are similar to plant cells
others are more like animal cells

Question 23

bacteria

Answer 23

single celled
very very small
dont have a nucleus, instead they have circular chromosomes of DNA
some can photosynthesise
most feed off other organisms living and dead

Question 24

viruses

Answer 24

particles
can only perform the living functions inside living cells - they are parasites
infect all types of living organisms
come in loads of different shapes and sizes
they dont have a cellular structure, rather a protein coat around some genetic material (RNA/DNA)

Question 25

cell wall

Answer 25

a rigid structure made of cellulose that surrounds the cell membrane and supports the cell

Question 26

vacuole

Answer 26

contains cell sap that support the cell

Question 27

chloroplast

Answer 27

photosynthesise which makes food for the plant. contains chlorophyll which is used in photosynthesis and gives the leaf its green colour

Question 28

saprotrophic nutrition

Answer 28

where extracellular enzymes are secreted into the area outside their body to dissolve their food, leaving nutrients that can be absorbed by the fungi

Question 29

pathogenic protoctists

Answer 29

plasmodium which causes malaria

Question 30

pathogenic bacterium

Answer 30

pneumococcus which causes pneumonia

Question 31

pathogenic viruses

Answer 31

influenza virus, HIV, TMV for plants

Question 32

catalyst

Answer 32

a substance that increases the speed of a reaction without being changed or used up

Question 33

what are enzymes

Answer 33

proteins that are also biological catalysts for useful chemical reactions in our body

Question 34

lock and key

Answer 34

the substrate fits into an active site, both of them sharing a specific shape for a specific reaction

Question 35

factors requires to maintain enzymes

Answer 35

pH (7) temperature (37°C)

Question 36

active site

Answer 36

the part where the substrate joins on to the enzyme

Question 37

substrate

Answer 37

molecule that is changed in a reaction

Question 38

investigate how temperature affects enzyme activity by how fast a product appears (practical)

Answer 38

enzymes catalyse the breakdown of hydrogen peroxide into water and oxygen use a pipette to add a set amount of hydrogen peroxide to a boiling tube put the tube in a water bath at 10°C set up the apparatus (delivery tube into a measuring cylinder) add a source of catalase (e.g potato) to the hydrogen peroxide and quickly attach the bung record how much oxygen is produced in the first minute by reading the measuring cylinder. repeat and find a mean. repeat this at differing temperatures

Question 39

investigate how temperature affects enzyme activity by how fast a substrate disappears (practical)

Answer 39

the enzyme amalyse catalyses the breakdown of starch to maltose starch is detected by iodine solution set up the apparatus (solutions mixed and placed in a water bath, mixture sampled every 10 seconds, spotting tile filled with iodine solution) every ten seconds, drop a sample of the mixture into a well using a pipette. once the solution turns browny orange, record the total time taken. repeat with the water bath at different temperatures

Question 40

investigate how pH affects enzyme activity (practical)

Answer 40

same thing as the temperature practicals, but add a buffer solution with a different pH level to a series of different tubes containing the enzyme/substrate mixture

Question 41

diffusion

Answer 41

the net movement of particles from an area of high concentration to an area of lower concentration. happens in liquid and gases and doesnt require energy

Question 42

cell membrane diffusion

Answer 42

small molecules can diffuse through the cell membrane - amino acids, water, oxygen big molecules like starch and proteins cant fit through the membrane

Question 43

osmosis

Answer 43

the net movement of water molecules across a partially permeable membrane from a region of higher water concentration to lower water concentration

Question 44

investigate diffusion in a non living system (practical)

Answer 44

phenolphthalein is a pH indicator thats pink in alkaline solution and colourless in acidic cut some agar jelly made of phenolphthalein at equal sizes put sone dilute hydrochloric acid in a beaker. put some cubes in the beaker of acid leave the cubes for a while. when you come back, they should turn colourless as the acid diffuses into the agar jelly

Question 45

investigate osmosis in a non living system (practical)

Answer 45

fix some visking tubing over the end of a thistle funnel. pour some sugar solution down the glass tube ito the thistle funnel put the thistle funnel into a beaker of pure water and measure where the solution comes up to on the glass tube leave the apparatus overnight then measure where the solution is in the glass tube. water should be drawn through the visking tubing by osmosis and this will force the solution up the glass tube

Question 46

investigate osmosis in a living system (practical)

Answer 46

cut up potatoes into identical cylinders using a cork borer, and get some beakers filled with different sugar solutions in them one should be pure water and the other should be a very concentrated sugar solution. then, there should be concentrations in between. weigh the mass of each potato before dropping them into each beaker for like half an hour or something slightly dab at the potatoes with tissues to dry them lightly, then reweigh their mass.

Question 47

active transport

Answer 47

the movement of particles against a concentration gradient from an area of lower concentration to an area of higher concentration using energy released from respiration

Question 48

factors that affect the movement of substance

Answer 48

surface area : volume distance temperature concentration gradient

Question 49

surface area : volume

Answer 49

the larger the surface area : volume ratio, the faster substances are able to move in and out of a cell

Question 50

distance

Answer 50

if substances have a shorter distance to move, then theyll move in and out of a cell faster

Question 51

temperature

Answer 51

as the particles in a substance get warmer, they have more energy so they move faster. as the temperature increases, substances move in and out of a cell faster

Question 52

concentration gradient

Answer 52

if theres a big difference in concentration, substances move in and out of a cell faster this factor only affects diffusion and osmosis