Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Edexcel Biology > Topic 1: Key Concepts in Biology > Flashcards

Topic 1: Key Concepts in Biology Flashcards

1
Q

label animal cell diagram

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

role of a nucleus

A

contains genetic material that controls activities of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

role of cytoplasm

A

gel-like substance which contains enzymes where most chemical reactions happen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

role of cell membrane

A

holds cell together and contorls what goes in and out of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

role of mitochondria

A

respiration takes place to produce ATP for metabolic reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

role of ribosomes

A

involved in translation of genetic material in the synthesis of proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

label plant cell

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

role of cell wall

A

made of cellulose, it supports cells and strengthens it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

role of vacuole

A

contains cell sap, and maintains internal pressure of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

role of chloroplasts

A

photosynthesis occurs here and contain chlorophyll

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

label bacteria cell

A

NO NUCLEUS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

role of chromosomal DNA

A

controls cell’s activities and replications and floats in cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

role of plasmid DNA

A

small loops of extra DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

role of flagellum

A

long hair-like structure that rotates to make bacterium move away from toxins and towards nutrients for oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

label egg cell

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the main function of an egg cell

A

carry female DNA and nourish the developing embryo in early stages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

explain how is an egg cell adapted to its function

A
  • contains nutrients in cytoplasm to feed embryo
  • has a haploid nucleus
  • immediately after fertilisation membrane changes structure to stop any more sperm getting in so offspring end up with right amount on DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the function of a sperm cell

A

transport male DNA to female egg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how is a sperm cell adapted to its function

A
  • long tail so it can swim to the egg
  • lots of mitochondria in the middle section to provide the energy needed to swim
  • acrosome at the tip of the sperm head and stores enzymes needed to digest the membrane of the egg cell
  • haploid nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how are ciliated epithelial cells adapted to their function

A

cilia line tubes (e.g. trachea and oviduct) and contain strands of a substance which can contract, causing wavy side to side movement to sweep substances along (e.g. mucus/ova).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

define resoultion

A

how well a microscpe can distinguish between two points that are close together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

define a high resolution

A

image can be seen more clearly and in more detail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how do light microscopes work

A

light passes through the specimen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what cell structures can we see using a light microscope

A

internal structures like the nucleus and chloroplasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what type of cells can be studied under a light microscope

A

both live and dead specimens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how do electorn microscopes work

A

fire electrons at specimen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what structures canelectron microscope show

A

internal structures of mitochondria and chloroplasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what type of specimens can an electorn microscope investigate

A

only dead specimens as they work in a vaccum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Core Practical: How to View a Specimen Using a Light Microscope

A
  1. cut a thin slice of the specimen
  2. take a clean slide and use a pipette to put one drop of water in the middle of it, then use tweezers to place the specimen sample on the slide
  3. add a drop of stain (if sample is transparent or colourless)
  4. place a cover slip at one end of the specimen, holding it at an angle with a mounted needle and carefully lower it onto the slide. Press down gently and clip the slide onto the stage
  5. select the lowest powered objective lens
  6. use coarse adjustment knob to move the stage up so that the slide is just underneath the objective lens. Then looking sown the eyepiece, move the stage downwards until secimen is nearly in focus
  7. adjust the focus using the fine adjustment knob, until you get a clear image. Position a clear rules on the stage and use it to measure the miameter of the circular area visible (your field of view FOV)
  8. if you need to see your specimen with greater magnification, swap to a high power objective lens, refocus and recalculate your FOV accordingly
30
Q

“Core Practical: How to View a Specimen Using a Light Microscope
why does the slice of specimen have to be thin”

A

so that light can pass through it

31
Q

“Core Practical: How to View a Specimen Using a Light Microscope
why do you have to put a drop of water on the slide?”

A

it will secure the specimen in place

32
Q

“Core Practical: How to View a Specimen Using a Light Microscope
why do you add stain to sample on the slide”

A

makes the specimen easier to see as it highlights different strcutures within cells e.g. methylene blue stains DNA

33
Q

“Core Practical: How to View a Specimen Using a Light Microscope
why do you press the cover slip down gently”

A

so no air bubbles are trapped under it

34
Q

label diagram of light microscope

A
35
Q

Core Practical: How to Create a Scientific Drawing of a Specimen

A
  1. using a sharp pencil, draw outlines of the main features using clear, unbroken lines.
  2. NO COLOURING OR SHADING
  3. drawing must take up at least half of the space provided in exam and keep all parts in proportion
  4. label important features with straight lines which don’t cross over
  5. include magnification and scale used
36
Q

formula for working out total magnification of an image (if you know which lesnes were used)

A

total magnification = eyepiece lens magnification x objective lens magnification

37
Q

formula for working out total magnification of an image if you don’t know which lenses were used

A

magnification = image size/ actual size

38
Q

table to convert mm -> micrometer -> nm -> picometer

A
39
Q

define catalyst

A

a substance which increases the speed of a reaction, without being changed or used up in the reaction

40
Q

define enzyme

A

a biological catalyst

41
Q

describe ‘Lock and Key’ mechanism of synthesising substrates

A
  1. every enzyme has a specific shape of the active site
  2. it is complementary to a specific substrate
  3. substrate fits into the specific active sites and binds where it gets broken apart into its products
42
Q

what happens if substrates shape doesn’t match the enzyme’s active site shape

A

the reaction wont be catalysed

43
Q

explain how changing temperature affects the rate of reaction and include graph

A
  • as temp increases so does the rate of reaction
  • until optimum temperature
  • the bonds holding the enzyme together break which changes the shape of the active site so the substrate no longer fits anymore. the enzyme is denatured so they cannot be used.
    this decreases the rate of reaction
44
Q

explain how changing pH affects rate of reaction

A
  • the if too low or too high pH can break bonds within the enzyme which changes the shape of the active site so substrate can no longer fit
  • all enzymes have an optimum pH so creates a bell-shaed curve
45
Q

explain how changing substrate concentraiton affect the rate of reaction

A
  • the higher the substrate concentration, the faster the reaction as its more likely that substrate will bind to the enzyme.
  • only happens up to a point. after that there are more substrate molecules than there are enzymes because all the active sites are full so the rate of reaction plateus
46
Q

Core Practical: effect of pH on enzyme activity METHOD

A
  1. put a drop of iodine solution into every well of a spotting tile
  2. place a bunsen burner on a heat prof met, and a trpod and gauze over the bunsen. Out a beaker of water of top of thw tripod and heat until the water reacher 35 dgerees (use a thermometer) try to keep the temperature onstant
  3. use a syringe to add 3cm^3 of amylase solution and 1cm^3 of buffer solution with a ph of 5 to a boiling tube. using test tube holders, put the boiling tube into the beaker of water and wait for 5 minutes.
  4. next, use a different syringe to add 3cm^3 if starch solution to the boiling tube
  5. immediately mix the xontents of the boiling tube and start a stop clock
  6. use continuous sampling to record how long it takes for the amylase to break down all of the starch. to do this, use a dropping pipette to take a fresh sample from the boiling tube every10 seconds and put a drop into a well. when the iodine solution remains browny-orange, starch is no longer present.
  7. repeat the whole experiment with buffer solutions of different pH values to see how pH affects the time taken for the starch to be broken down
  8. remember to control any variables each time (concentration and volume of amylase solution)
47
Q

Core Practical: effect of pH on enzyme activity
how else can the temperature of the water be controlled instead of using a bunsen and thermometer

A

use an electric water bath

48
Q

Core Practical: effect of pH on enzyme

what can you use to accuratley measure the pH of your solutions

A

pH meter

49
Q

how to calculate the rate of reaction

A

rate = 1000/ time

50
Q

give an example as to why enzymes break down big molecules

A
  • food moleucles can be too big to pass through the walls of digestive system so digestive enzymes break them down into smaller, more soluble molecules which can be basorbed into the blood stream and pass into ells to be used y the body.
  • plants store energy in the from of starch and enzymes break this down into smaller sugars so they can be rrespired to release energy to be used by cells.
51
Q

what enzyme breaks down carbohydrates and what are they broken down into

A

amylase breaks down carbohydrates into maltose

52
Q

what enzyme breaks down proteins and what are they broken down into

A

proteases break down proteins into amino acids

53
Q

what enzyme breaks down lipids and what are they broken down into

A

lipases convert lipids into glycerol and fatty acids

54
Q

how are carbohydrates synthesised

A

joining together simple sugars (maltose)

55
Q

which enzymes joins glucose molecules together to make glycogen

A

glycogen synthase

56
Q

what reagent do you use to test for reducing sugars

A

benedicts reagent

57
Q

describe the test for reducing sugars

A
  • add blue benedicts reagent to a sample and heat in water bath at 75 degrees.
  • if the test is posiitve then the coloured precipitate will form
  • the higher the concentration of the reducing sugar, the further the colour change goes.
  • blue to orange to brick red
58
Q

how do you test for starch

A
  • add iodine solution to the test sample
  • if starch is present, sample changes from browny-orange to a blue-black colour
  • if no starch is present then colour stays an orange
59
Q

describe the emulsion test for lipids

A
  • shake test substance with ethanol until it dissolves then pour the solution into water
  • if lipids are present, they will precipitate and form a milky emulsion
  • the more lipid present, the more precipitate will form and the more milky the colour will be.
60
Q

what test is used to test for proteins

A

biuret test

61
Q

describe the biuret test for proteins

A
  • add a few drops of potassium hydroxide solution to make the solution alkaline
  • add some blue copper(II) sulphate solution
  • if proteins are present then solution will turn purple
62
Q

what is the name of the experiment for testing how much energy food contains

A

calorimetry

63
Q

describe the method for calorimetry experiment

A
  • need food that will burn easily e.g. dried beans, pasta, bread.
  • weigh a small amount of the food and then skewer it on a mounted needle
  • add a set volume of water to a boiling tube held with a clamp (this will be used to measure the amount of energy that’s transferred when food is burned)
  • measure the temperature of the water, then set fire to the food using a bunsen flame (MAKE SURE BUNSEN ISNT NEAR THE WATER OR IT WILL ALTER RESULTS)
  • hold burning food under the boiling tube until it goes out. then relight the food and hold it under the tube. repeat this intil the food wont catch fire again.
  • measure temperature of the water again.
64
Q

how to calculate the amount of energy released from the food from a calorimetry experiment

A
  • work out how many joules of energy the food contains using this formula:
    energy in food = mass of water (g) X tep chnage in degrees X 4.2
  • then work out how many joules are in each gram of the food.
    energy per gram of food = energy in food (J) / mass of food (g)
65
Q

define diffusion

A

the overall net movement of particles from an area of higher concentration to an area of lower concentration down a concentration gradient

66
Q

define osmosis

A

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

67
Q

what is a partially permeable membrane

A

a mebrane with very small holes in it so small molecules can pass through but not bigger molecules

68
Q

define active transport

A

the movement of particles across a membrane against a concentration gradient ( from an area of low concentration to an area of high concentration) using energy transferred during respiration

69
Q

describe the differences between active transpot and diffusion

A
  • in active transport particles move up and concentration gradient but in diffusion particles move down a concentration gradient
  • active transport requires energy released from respiration whereas diffusion is a passive process
70
Q

describe the practical which investigates osmosis

A
  • prepare sucrose solutions of different concentrations ranging from pure water to a very concentrated sucrose solution
  • use a cork borer to cut a potato into the same sized pieces (in about 1cm thick pieces and preferably from the same potato)
  • divide cylinders into groups of 3 and use a mass balance to measure the mass of each group
  • place one group in each solution
  • leave cylinders in the solution for at least 40 minutes
  • remove cylinders and genlty pat dry with a paper towel. this removes excess water from the surface of the cylinders, so you get a more accurate measurement of thier final masses.
  • weigh each group again and record your results.
    the only thing that should be changed in this experiment is the sucrose solution concentration, everythigb else e.g. temperature, volume of solution, size of potato cylinders should be kept constant
71
Q

how do you interpret results from the practical on investigating osmosis

A

find percentage change in mass of each group of cylinders
- plot a graph using that data
- at the points above x-axis, water concentration of sucrose solutions is higher than the cylinders. the cylinders gain mass as water is drawn by osmosis.
- where there is no change in mass (curve crosses the x-axis) the fluid inside the cylinders and the sucrose solution are isotonic - they have the same water concentration
- at the points below the x-axis the water concentration of the sucrose solutions is lower than in the cylinders. this causes the cylinders to lose water so thier mass decreases

72
Q
A

Edexcel Biology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions