Cells

Question 1

What are Cells

Answer 1

The building blocks of life, all living things are made out of cells

Question 2

What are groups of cells called

Answer 2

Tissue

Question 3

What are groups of tissue called

Answer 3

An organ

Question 4

unicellular

Answer 4

organisms made up of only one cell

Question 5

multi-cellular

Answer 5

organisms made up of multiple cell

Question 6

what is the mnemonic for the seven life processes that are need for an organism to stay alive

Answer 6

MRS GREN

Question 7

What does MRS GREN stand for

Answer 7

Movement - The organism can change its position
Respiration - The organism releases energy from a ‘food’ source, this requires oxygen
Sensitivity - The organism responds to things
Growth - The organism gets bigger
Reproduction - The organism makes copies of themselves
Excretion - The organism gets rid of waste material
Nutrition - The organism consumes chemical
material as food

Question 8

Eukaryotic Cell

Answer 8

Can be both Unicellular and Multi-Cellular
A type of cell with a nucleus containing DNA and other membrane-bound organelles is called a eukaryotic cell
Size - 2-200μm
(e.g. Animal Cell, Plant Cell or Fungi Cell)

Question 9

Prokaryotic Cell

Answer 9

Can only be Unicellular
Are much smaller than eukaryotic cells (Less than 2μm)
No membrane-bound organelles
Have a cell wall – but it isn’t made of cellulose like a plant cell wall (made of peptidoglycan)
Doesn’t have a nucleus
Can’t store genetic material in a nucleus (it is a single DNA loop)
May have one or more small rings of DNA called plasmids
(e.g. Bacteria Cells)

Question 10

What sub-cellular structures (organelles) do animal cells contain

Answer 10

a nucleus
cyctoplasm
a cell membrane
mitochondria
ribosomes

Question 11

What sub-cellular structures (organelles) do plant cells contain

Answer 11

a nucleus
cyctoplasm
a cell membrane
mitochondria
ribosomes
chloroplasts
a permanent vacuole filled with cell sap
cell wall

Question 12

Function of Nucleus

Answer 12

Controls the activities of the cell

Contains DNA

Question 13

Function of Cell Membrane

Answer 13

Controls what passes in & out of a cell

Question 14

Function of Cell Membrane

Answer 14

Holds the cell together

Controls what passes in & out of a cell

Question 15

Function of Ribosome

Answer 15

Site of protein synthesis (where proteins are made)

Question 16

Function of Cell Wall

Answer 16

Gives the cell a rigid strong structure
Made of cellulose
Keeps shape of cell box-like

Question 17

Function of Vacuole

Answer 17

Contains sap

Helps support the shape of the cell

Question 18

Function of Chloroplast

Answer 18

Contains Chlorophyll (needed for photosynthesis) (green in colour)

Question 19

Function of Vacuole

Answer 19

Contains Cell Sap

Helps support the shape of the cell

Question 20

Function of Cell Sap

Answer 20

Stores materials such as sugars, amino acids, waste substances (such as tannins), and mineral salts

Question 21

How to draw a diagram of an animal cell

Answer 21

Oval like structure for Cell Membrane
In centre of Oval is the One Nucleus which is a circle
Cytoplasm is around it
Ribosomes are dots scattered around
Mitochondria are fewer than Ribosomes and look like a baguette

Question 22

How to draw a diagram of a plant cell

Answer 22

Rectangular box-like structure for Cell Membrane
A slightly bigger rectangle around Cell Membrane for Cell Wall
In centre of Box is the Vacuole which is big and covers most of the space - quite box like as well
Cytoplasm is around it
The One Nucleus is a circle in the cytoplasm area
Ribosomes are dots scattered around
Mitochondria are fewer than Ribosomes and look like a baguette
Chloroplasts are Ovals slightly bigger than Mitochondria but have no baguette design (sometimes green)

Question 23

How big is an animal cell usually

Answer 23

1/100mm

Question 24

How big is a plant cell usually

Answer 24

40 times as big as an animal cell

Question 25

What sub-cellular structures (organelles) do bacteria cells contain

Answer 25

``` cytoplasm cell membrane cell wall ribosomes flagella circular DNA capsule plasmid Pili ```

Question 26

Function of Capsule (most bacteria)

Answer 26

Protection from damage For sticking prokaryotic cells together Slimy or Gelatine-like

Question 27

Function of Flagella/Flagellum (some bacteria)

Answer 27

Movement | A long protein strand that lashes about helping them to move

Question 28

Function of Pili (some bacteria)

Answer 28

For movement For sticking to surfaces (e.g. bacteria may stick to body cells to begin causing disease)

Question 29

Function of Plasmid (some bacteria)

Answer 29

Extra bits of circular DNA, genes in the plasmids can be for antibiotic resistance Some produce toxins

Question 30

How to draw a diagram of a bacteria cell

Answer 30

Cell Membrane is a capsule / oval structure Cell wall is a slightly bigger oval structure surrounding the Cell Membrane Capsule is a slightly bigger oval structure surrounding the Cell Wall Genetic material is free and not contained in a nucleus. The bacterial chromosome or long strand of DNA is usually circular. Draw it as a line in the middle of the oval weaving in and out of itself the connecting back up to the start in the end Plasmids are also like this strand but are separate and are circular looking Pili are strands coming out in all directions outwards from the capsule (look like legs of a centipede) Ribosomes are dots scattered around Flagella is a tail coming out from the shorter end of the bacteria cell usually the right hand side

Question 31

Similarities between Eukaryotes and Prokaryotes

Answer 31

A plasma membrane Cytoplasm Ribosomes for protein synthesis DNA and RNA

Question 32

Why Prokaryotes are different from Eukaryotes

Answer 32

They have no nucleus They have linear chromosomes They have no membrane bound organelles They have larger ribosomes Their cell wall is made of peptidoglycan and not cellulose or chitin (fungi cells walls) Have a less well developed cytoplasm with no centrioles (centrioles are involved in cell division which will be covered later) (Some bacterial cells also have a slime/waxy capsule, plasmids, flagella and pili)

Question 33

Pre 1970 what system of classification was used

Answer 33

Five Kingdoms Monera - Prokaryotes (Bacteria + Archaea) Prostita - Anything else (e.g. Amoeba + Algae) Plantae - Plants Fungi - Fungi Animalia - Animals They were classified on observable traits

Question 34

What are Archaea

Answer 34

Small, single-celled organisms that live in extreme environments (extremophiles) Size and structure of Archaea ribosomes are the same as bacteria BUT the nucleic acids in the ribosomes are more similar to Eukaryotes Also Cell Wall didn't contain peptidoglycan which Bacteria did but did have other materials in cell wall that bacteria did have (Proteins, Lipids, and Polysaccharides) In 1977 Carl Woese decided if these organisms lived in these extreme environments, they must be something different

Question 35

Post 1970 what system of classification was used

Answer 35

Three Domains Bacteria - all types of bacteria Archaea - all types of archaea Eukarya - all Eukaryotes including Plants, Animals, Fungi, Protists and more

Question 36

Structure of a Light Microscope (14 parts) | From top to bottom

Answer 36

``` eyepiece lens body tube arm revolving nosepiece low power objective lens medium powered objective lens high powered objective lens stage clip stage diaphragm fine focusing knob coarse focusing knob light source base ```

Question 37

What is magnification

Answer 37

The ability of a lens or other optical instrument to magnify (enlarge) the size of something in an optical image.  

Question 38

How is the magnified image produced

Answer 38

Two lenses, an eyepiece lens (fixed) and an objective lens (can choose).

Question 39

How do you find the total magnification

Answer 39

Magnification of Eye Piece Lens (fixed to x10) * Magnification of Objective Lens

Question 40

What is resolution

Answer 40

Ability of a microscope to distinguish two adjacent points as separate from one another. Maximum resolution is the smallest distance between two points, at which they may be recognised as two separate entities. The better the resolution, the better you are able to view and identify finer details.

Question 41

What is need in a Scientific Drawing

Answer 41

No shading. Areas that should be shaded should be labelled instead. Clear, continuous lines The drawing should take up at least half of the page. Label lines must be completely horizontal, drawn with a ruler, exactly touch the object that they’re labelling and must not overlap each other. Drawing lines should completely connect. They should be drawn in a sharp pencil and look like the actual image. Include a title Include a scale if relevant Also include total magnification if you are drawing a diagram of something under a microscope Labels should be off the diagram Include annotation - colour, function, adaption for example

Question 42

What are the two types of microscopes

Answer 42

Light Microscope | Electron Microscope

Question 43

Advantages of a Light Microscope

Answer 43

``` Cheaper Can see specimens in colour Can use Living/Dead specimens Mobile / Portable Can see outside of the cells and nucleus ```

Question 44

Disadvantages of a Light Microscope

Answer 44

Lower Magnification than Electron Microscope (x2,000) | Lower Resolution than Electron Microscope (around 200nm)

Question 45

Advantages of an Electron Microscope

Answer 45

Higher Magnification than Light Microscope (up to x2,000,000) Higher Resolution than Light Microscope (around 0.1nm) No complex lighting system needed Can see inside of the cell

Question 46

Disadvantages of an Electron Microscope

Answer 46

``` Costs approx. £1M Expert preparation Affected by magnetic fields Maintenance Cost Dead Specimen only Difficult to create sample Fixed / Large No colour (only B&W) ```

Question 47

What are the two types of electron microscope and how are they different

Answer 47

SEM - Scanning Electron Microscope - Scans surface of a sample TEM - Transmission Electron Microscope - Electrons penetrate the sample

Question 48

Size of various objects

Answer 48

The smallest thing we can see is about 0.04mm Most cells are so small so we used the unit micrometre (μm) Viruses and organelles are even smaller – so we can use the unit nanometre (nm)

Question 49

Centimetre (cm) to Millimetre (mm)

Answer 49

x10

Question 50

Millimetre (mm) to Micrometre (µm)

Answer 50

x1,000

Question 51

Micrometre (µm) to Nanometre (nm)

Answer 51

x1,000

Question 52

How do you calculate Magnification

Answer 52

Size of Image / Size of Actual Object Remember this as the I AM triangle I is on the top while AM is on the bottom. (This is like the Speed, Distance, Time Triangle or Density, Mass, Volume Triangle)

Question 53

What is Standard Form and why is it used

Answer 53

A * 10^n (1≤A<10) and (n has to be an integer) Some numbers may be too big or too small to read or even understand. Writing numbers in standard form makes them easier to comprehend and compare. Also, a calculator may not be able to handle all the numbers in a very large calculation, but by using standard form it can handle numbers of any size.

Question 54

Standard Form Equivalent of a Millimetre (mm) in Metres (m)

Answer 54

10^-3

Question 55

Standard Form Equivalent of a Micrometre (µm) in Metres (m)

Answer 55

10^-6

Question 56

Standard Form Equivalent of a Nanometre (nm) in Metres (m)

Answer 56

10^-9

Question 57

What is Order of Magnitude

Answer 57

The difference in size in factors of 10 (e.g. if order of magnitude = 1, something is 10x bigger If order of magnitude = 3, something is 1000x bigger (10x10x10)

Question 58

How to calculate Order of Magnitude

Answer 58

``` Convert to same unit Convert that to Standard Form Subtract the smaller value from the bigger value (e.g. 1µm = 0.000001 = 1x10^-6m 100nm = 0.0000001 = 1x10^-7m Order of Magnitude = 1 (-6 - -7 = 1) ```