Biology Year 9 cell structure

What is a Tissue

a collection of cells with a single purpose

What is the Organ system

a group of different organs

What is an Enzyme?

is a biological catalyst which are produced by living things and they are made from proteins. They don't get used up.

What is the activation energy

The minimum amount of energy used to for a reaction to take place.

Describe the function of the cell membrane

Controls substance into and out of the cell

Explain the difference between Photosynthesis and respiration?

Photosynthesis requires sunlight, carbon dioxide, and water, while respiration requires glucose and oxygen.

What is the difference between the terms magnification and resolution?

Magnification is the ability to make small objects seem larger, such as making a
microscopic organism visible. Resolution is the ability to distinguish two objects
from each other.

Where is genetic material contained?

Inside the nucleus

What does the Nucleus contain

Contains genetic material

function of Cytoplasm

Where most chemical reactions occur

function of Ribosomes

Protein sysnthesis occurs here

function of cell membrane?

Controls substance into and out of the cell

What does the cell wall contain

Contains Cellulose to give the cell structure

function of chloroplast?

Contrains chlorophyll, which absorbs light for photosynthesis.

What does the vacuole contain

Cell sap

What is released in mitochondria

Engery is released via aerobic respiration

What subcellular structures do plants cells have but animal cells don't?

Chloroplast, cell wall, vacuole

Where does respiration occur and what is released?

Respiration occurs inside the mitochondria which releases energy for the cell. This is a form of aerobic respiration.

Label a prokaryotic cell

It is a smaller and simpler, single cell organism which contains: Cell wall, plasmids, flagellum, cell membrane, single circular stand of DNA, Cytoplasm.

Describe the prokaryotic cell

· The prokaryotic cells use the flagellum to move.
· Prokaryotic cells are smaller in size and less complex than
eukaryotic cells.
· Prokaryotic cells contain DNA in the plasmid and a single
circular strand of DNA

examples of specialised cells?

Sperm cell, muscle cell, nerve cell, root hair cell, red blood cell, palisade cell.

Function and adaptation for sperm cell

Function: Combine male DNA with Female DNA.
Adaptation: Long tain for swimming and head contains enzymes to help enter egg cell
It is found in testes

Function and adaptation for muscle cell

Function: To contract quickly, help us move
Adaptation: Long and contain lots of mitochondria to release energy
Found in: muscles.

Function and adaptation for Nerve cell

Function: To carry out electrical signals to different parts of the body
Adpatation: Long, many branches for connections
Found in: nervous system

Function and adaptation for root hair cell

Function: to absorb water and minerals
Adaptation: Many small hairs give a large surface area
Found in: roots of plants

Function and adaptation for Red blood cell

Function: to carry oxygen and remove CO2.
Adaptation: No nucleus, large surface area, for maximum oxygen uptake.
Found in: the blood

Function and adaptation for Palisade cell

Function: to absorb sunlight for photosynthesis
Adaptation: large surface area and many chloroplast to absorb sunlight

Function and adaptation of xylem cell

Function: transport water and minerals from roots to the rest of the plant.
Adaptation: Hollow tube - allows xylem to transport water and mineral ions from roots to rest of plant. Ligning - provides strength and support for plants

Function and adaptation of phloem cell

Function transport sugars and other organic molecules throughout the plant, a process known as translocation

Adaptaion: Cells have end walls with perforation, Two way flow

Describe the xylem ?

One-way only, carries water and minerals. No end walls between cells. Thick walls stiffened with lignin.

Describe the phloem?

two way only. Cells have end walls with perforations.
Carries water and food.

Give 2 substances that strengthen the xylem

Cellulose and lignin

What are companion cells

Companion cells ( attached to the phloem ) assist in the movement of sugar through the phloem. This is an active process ( requires energy)

How do companion cells assist with this?

They contain many mitochondria which release energy via aerobic respiration

What is specialisation?

The different types of cells in our bod were once stem cells that went through a process called differenatiation to become specialised.

What do specialised cells have?

A specialised cell has structural adaptations that help it to carry out a specific function.

Are cell walls found in plant cells, animal cells and/or bacterium

Plant cells & bacterium

Are cell membrane found in plant cells, animal cells and/or bacterium

Plant, animal and bacterium

Are cytoplasm found in plant cells, animal cells and/or bacterium

Plant, animal & bacterium

Are mitochondria found in plant cells, animal cells and/or bacterium

Plant and animal cells only

Are Ribosomes found in plant cells, animal cells and/or bacterium

Plant, animal and bacterium

Are chloroplasts found in plant cells, animal cells and/or bacterium

Only found in plants

Are Nucleus found in plant cells, animal cells and/or bacterium

Plants & animal cells

Are plasmids found in plant cells, animal cells and/or bacterium

only in bacterium

What is the size of most eukaryotes?

5-100 ( micromter) um

What is the size of most prokaryotes

0.2-2 ( micometer) um

What does the eyepiece lens do on a microscope?

Magnifies the image

What does the coarse adjustment do?

for rough focusing

What does the fine adjustment do?

for fine focusing

What does the clip do?

hold the slide

What does the stage height adjustment do?

to allow the long, high powder lens to fit over the slide

What does the nosepiece do?

Revolvves to move the desired lens into position

What does the objective lens do?

magnifies the image

What does the stage do?

Holds the slide, which ontains the object

What does the diaphram lever do?

controls the amount of light reaching the object

What does the condenser do?

focuses light on the pbject; may not be present in all microscopes.

What does the mirror or light souce do?

to supply light to the object

How to calculate total lens

eyepiece lens x Objective lens = total lens

What magnification does the eyepiece lens have?

x10 magnification

what does the red coloured lens mean?

x4 magnification. It is the shortest lens

What does the yellow coloured lens mean?

x10 magnification ( medium lens)

What does the blue coloured lens mean?

x40 magnification ( longest lens )

Centimetre (Cm) to Millimetre ( mm)

x10

Millimetre ( mm) to micrometre
( um)

x 1000

Micrometre ( um ) to nanometre ( nm )

x 1000

How to use a light microscope?

1. Clip the slide onto the stage.
2. Select the lowest magnification first.
3. Look through the eye piece.
4. Use the coarse focus to move the stage up until the image is in view.
5. Use the fine focus to make the image sharp/clear.
6. For greater magnification swap the higher objective lens

How to prepare a slide ( onion )

1. cut a piece of onion and separate top layers.
2. Use tweezers to carefully place the Epithelial ( outer later ) tissue onto the slide.
3. Add a drop of iodine solution. This stains the onion, making organelles easier to see.
4. Place a cover slip on top. Tilt from an angle when placing to avoid air bubbles under the slide.

How to draw an observation

1. start by using a sharp pencil for accuracy.
2. Draw with clear unbroken lines
3. Do not include shading or colour
   Draw structures in proportion.
   Always write the magnification used to observe.
   Label clearly using straight uncrossed lines.

What is magnification?

The number of times bigger the image size is compared to the real size

What is resolution?

The ability to distinguish between two points, i.e. how detailed the image is.

Compare a light microscope to a electron microscope?

Magnification = electron has a higher magnification
Resolution Electron has a higher microscope.
Size = electron is bigger fixed, the light is portable
Biological material = Electron can only view dead only and light can view both alive and dead.

How to calculate magnification

Image size = actual size x magnification

Specimen size and actual size

Image size and speciment ( actual ) size must have the same units.

How does bacteria ( microorganism) multiply?

simple cell division

How does bacteria divide?

Binary Fisson

What should the medium contain when bacteria are grown ( cultured ) ?

A liquid or gel that contains carbohydrates for energy and nitrogen for building proteins.

What happends when bacteria grows on agar jelly

Bacteria grown on agar plates will form visible colonies on the surfacr of the jelly or will spread out to give an even covering.

Why would we want to culture mucroorganisms?

Investigate effects of antibiotics
investigate effects of disingectants.

What could contaminate your sample?

Airborne bacteria
Bacteria from your skin, water or soil samples.

Write a three stage method, of how to prepare an uncontaminated culture of bacteria? ( 6mark)
Stage 1?

1. sterilise the petri dish and nutrient agar to kill any unwanted microorganisms. UV light, gamma rays or an autoclave oven can be used.
2. Next sterilise the inoculating loop, by passing it through a flam to kill of unwanted microorganisms.

Stage 2 of preparing uncontaminated culture practical?

3. Inoculate the sterile agar with the microoganism you want to grow evenly across agar.
4. Work near a flame to remove any airborne microorganisms ( convection current )

Stage 3 of preparing uncontaminated culture practical?

5. Cover with a lid and tape closed to prevent unwanted airborne contamination or microorganisms escaping.
6. Place in an incubator at 25 degrees celcius to promote growth
7. Store upside down to prevent condensation falling on the agar.

Why do schools not raise the incubator temperatures abover 25 degrees celcius?

Growing bacteria at closer to 37 degrees ( body temperature ) creates a very high chance of growing harmful pathogens.

What might limit the growth of bacteria in a pertri dish

1. Lack of nutrients in agar
2. Competition between microorganisms
3. Lack of oxygen
4. incorrect temperature for growth
   5 pH level.

What is the independent variable in the effective ness of antibiotics or disinfectant?

The different antibiotics/ disinfectant

What is the dependent variable in the effective ness of antibiotics or disinfectant?

Zone of inhibition

What is the control variable in the effective ness of antibiotics or disinfectant?

Types of bacteria, an actual control disk, size of paper disk

Write a 10 step method of the effectiveness of antibiotics experiment.

1. Section base of your petri dish into quarters - label them.
2. Try to keep the lid on for as long as possible
3. Sterilise inoculating loop through blue flame for 5 secods.
4. Inoculat the Ecoli ( bacteria) onto the agar and use the sterile speader to evenly spread this across the dish ( do not break the surface of the agar)
5. work near a flame throughout
6. Now use the small paper disc and place it into your first disinfectant - place onto the corresponding quarter
7. repeat for remaining discs, including a control with no disinfectant on it.
8. seal with tape on each side of the dish

What is the zone of inhibition

Area of no bacterial growth

Antibiotic present- ineffective

bacteria are resistant to this antibiotic.

What do aseptic techniques ensure?

The microorganisms being investigated do not escape or become contaminated with an unwanted microorganism

List the aseptic techniques when culturing bacteria.

• no eating or drinking in the lab

1. wiping benches with disinfectant
2. not growing microorganisms at body temperature
3. using sterile loops when transderring
   flaming culture bottle necks to prevent
4. contamination
   wash hands
5. only removing petri dish lids when necessary

How to calculate the zone of inhibition

Measue the diameter and divide by 2 to find radius
Equation: area of inhibition zone = pie r squared

How can we test for the effectiveness of the an antibiotic or disinfectant?

We can test the effectiveness of different antibiotics or disnfectants by measuring the size of the inhibition zone around the paper circle that has been covered in the antibiotic or disnfectant.

What is the independant, dependant and control variables in testing for the effectiveness of the antibiotic

Independant: the different antibiotics/ disinfectant

dependant: zone of inhibition

control: Type of bacteria, an actual control disk, size of paper disk

What is aseptic

transferring bacteria without contamination

What is binary fission

Asexual reproduction by doubling

Nutrient broth solution

A soup like solution with nutrients for bacteria

Agar

Jelly which you put in the petri dish which grows bacteria

Colony

A group of bacteria