B1 Cell Biology Flashcards
(66 cards)
<p>Where are <strong>Eukaryotic </strong>cells found?</p>
<p>Eukaryotic cells are found in plants, animals, fungi and protists <em>(single-celled organisms that don’t fit other categories)</em></p>
<p>How large are <strong>Eukaryotic </strong>cells?</p>
<p>They are <strong>10 - 100 micrometres</strong> in size</p>
<p>What is a <strong>Eukaryote</strong>?</p>
<p>A eukaryote is an organism made up of eukaryotic cells</p>
<p>What is a <strong>prokaryote</strong>?</p>
<p>A prokaryote is a <strong>unicellular organism</strong> that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle</p>
<p>How large are <strong>prokaryotic </strong>cells?</p>
<p>Prokaryotic cells are <strong>0.1 - 5.0 micrometres</strong> in size</p>
<p>What are the <strong>key features</strong> of a <strong>Prokaryotic </strong>cell?</p>
<ul> <li>Plasmids - small ring/s of DNA</li> <li>No Mitochondria</li> <li>No chloroplasts</li> <li>Single DNA loop floating in Cytoplasm</li> </ul>
<p>What are the organelles found in an Animal Cell?</p>
<ul> <li>Cell membrane</li> <li>Nucleus</li> <li>Ribosomes</li> <li>Mitochondria</li> <li>Cytoplasm</li> </ul>
<p>What is the <strong>role </strong>of the <strong>Cell Membrane</strong>?</p>
<p>The cell membrane separates the interior (inside) of the cell from the environment outside
It is selectively permeable (it can control substances moving in and out of the cell)</p>
<p>What is the <strong>role </strong>of the <strong>nucleus </strong>in the cell?</p>
<p>The nucleus is the "control centre" of the cell It contains chromosomes (which contains the cells genetic material)</p>
<p>What is the role of <strong>Ribosomes</strong> in the cell?</p>
<p>Ribosomes perform protein synthesis<em> (making proteins)</em></p>
<p>What is the role of <strong>Mitochondria </strong>in the cell?</p>
<p>Mitochondria is where <strong>aerobic respiration</strong> takes place which supplies energy to the cell</p>
<p>What is the role of <strong>Cytoplasm </strong>in the cell?</p>
<p>Cytoplasm is a jelly-like fluid that fills the cell It is where most of the cell's <strong>chemical reactions</strong> take place</p>
<p>What organelles do a plant cell have that an animal doesn't?</p>
<ul> <li>Permanent Vacuole</li> <li>Chloroplasts</li> <li>Cell Wall</li> </ul>
<p>What is a <strong>vacuole</strong>?</p>
<p>A vacuole is a fluid-filled sac that stores water</p>
<p>It is enclosed in a membrane</p>
<p>It can make up as much as 90% of a plant cell’s volume</p>
<p>What do <strong>chloroplasts </strong>contain?</p>
<p>Chloroplasts contain Chlorophyll</p>
<p>What is <strong>chlorophyll </strong>needed for?</p>
<p>Chlorophyll are needed for photosynthesis</p>
<p>What is the cell wall made of?</p>
<p>The cell wall are made up of <strong>Cellulose</strong></p>
<p>What is the role of the cell wall?</p>
<p>The Cell wall makes the cell rigid and increases the structural strength of the cell</p>
<p>What type of cells are Bacteria?</p>
<p>Prokaryotic Cells</p>
<p>What are the sub-cellular structures in a Bacterial cell?</p>
<ul> <li>Some have Flagella</li> <li>Cell Wall</li> <li>Cell Membrane</li> <li>Cytoplasm</li> </ul>
<p>What are <strong>Flagella</strong>?</p>
<p>Flagella are whip-like structures used for movement</p>
<p>What are <strong>Plasmids</strong>?</p>
<p>Plasmids are small rings of DNA</p>
<p>What is <strong>Cell Differentiation</strong>?</p>
<p>Cell Differentiation is the process where a cell develops new sub-cellular structures (structures inside a cell) to let it perform a specific function</p>
<p>This makes a cell <b>Specialised</b></p>
<p>When does Cell Differentiation in <strong>animals </strong>mainly occur?</p>
<p>Cell differentiation in animals mainly happens in <strong>Embryos </strong></p>
<p>The cells divide to form embryos that differentiate (specialise) to produce cells that can perform all of the body's functions</p>
How are Sperm Cells specialised?
- Sperm cells have flagellum which helps it move towards the egg cell
- The middle section is filled with Mitochondria to provide the sperm with the energy it needs to travel to the egg cell
- The Acresome at the the tip of the cell contains enzymes to penetrate the egg
- The Nucleus contains half of an organisms genetic material. This combines with the egg's half to fertilise the egg cell
What are the key features of a Neurone (Nerve Cell)?
- Axon
- Myelin Sheath
- Dendrites
What is the Axon in a Neurone and how is it specialised?
The Axon is the part of the Neurone that electric signals travel along
It is long to increase the distance the electrical signal can travel
What is the Myelin Sheath in a Neurone and how is it specialised?
It is a sheath made of myelin that surrounds the Axon of the Neurone
This stops the electric nerve signals from leaking out the nerve cell. This increases the speed of transmission of electrical signals
What are Dendrites in a neurone and how is it specialised?
Dendrites are branches of the Nerve cell
Multiple Dendrites spread outwards from the cell to transfer the electrical messages to other neurones
How are Muscle cells specialised?
Protein Fibres within the cell can contract, allowing the muscle to move
There are lots of mitochondria in the cell which generate a lot of energy for motion
How are Root Hair cells specialised?
Long Projections which increase surface area that the plant can use to absorb water and minerals
The have no chloroplasts as they underground and don't receive light
How are Xylem cells specialised?
Xylem cells have Lignin (a substance) strengthens the cell walls
The Xylem tubes made up of dead cells that are hollow and have few subcellular structures to allow water to flow through
How are Phloem Cells specialised?
The end walls of phloem cells contain small holes to allow food products to move up and down the phloem vessels throughout the plant easily
Why are Xylem cells dead?
Xylem cells are dead so there aren't lots of organelles filling them up, so there is a larger capacity for transporting water
What is resolution?
Resolution is the ability to distinguish between (tell apart) two or more objects that are close together
What is the equation to calculate magnification?
Magnification = Image size ÷ Actual size
In which ways can bacteria be cultured?
- In Agar jelly
- On a Petri dish
- In a nutrient broth solution
What does a gene tell the cell?
Each gene tells the cell how to make a specific protein
What are the stages of the Cell Cycle?
What is the initial growth stage in the Cell Cycle?
Extra ribosomes, mitochondria and other sub-cellular structures are produced. The cell’s chromosomes (which are made of DNA) are replicated (copied) so that there are two sets of the cell’s chromosomes
What is Mitosis?
Mitosis is when a cell splits in two
What is the process of Mitosis?
Mitosis is a process that splits a cell and two genetically identical daughter cells is produced
What happens during Mitosis?
- Chromosomes are pulled apart
- The nucleus divides
- Two identical daughter cells are formed
What are Stem Cells?
Stem cells are undifferentiated cells that have not yet specialised to perform a specific function
They can create more stem cells or differentiate (become a different type of body cell) to perform another function
What are stem cells used for?
- Stem cell treatment
- Plant clones
- Therapeutic cloning
What are the disadvantages of Stem cells?
- Viral Infections
- Ethical Beliefs
Where are undifferentiated cells found?
- Bone Marrow
- Plant Meristems
- Embryos
How does Therapeutic cloning work?
Therapeutic cloning is a process that produces an embryo with the same genes as the patient.
Stem cells taken from this embryo will have the same DNA as the patient, so the patient's body will not reject the stem cells or body cells made from the stem cells
What is diffusion?
Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration
What factors affect the rate of diffusion?
- Temperature
- Concentration gradient
- Membrane surface area
What are exchange surfaces?
Exchange surfaces are surfaces that are adapted to maximise the efficiency of gas and solute (a substance dissolved in a liquid) exchange across them
What are the adaptions of an exchange surface?
- Thin Membrane
- Ventilation
- High Blood Supply
- Large Surface Area
Why does ventilation help maximise gas exchange?
If the surface is ventilated, a high concentration gradient is maintained which increases the rate of exchange
What is Osmosis?
Osmosis is the diffusion of water across a partially permeable membrane from a dilute solution (high concentration of water/high water potential) to a concentrated solution (low concentration of water/low water potential)
What is a partially permeable membrane?
A partially permeable membrane allows water molecules through, but not larger dissolved molecules
What is active transport?
Active transport is the net movement of molecules from a region of low concentration to high concentration - against the concentration gradient
When is active transport used in organisms?
- Sugar absorption in the gut
- Mineral absorption in Plants
Label The Prokaryotic Cell
Label the Plant Cell
Label the Animal Cell
What are the steps of Theraputic Cloning?
How does Diffusion in a leaf work?
How does Diffusion in the Lung work?
How does Diffusion in the liver work?
What is the method to see organelles in an Onion tissue?
- Peel off a thin layer of epidermal tissue from the inner surface of the Onion using forceps
- Make sure that the layer of onion cells is flat on the slide
- Put two drops of iodine solution onto the onion tissue
- Carefully lower a coverslip onto the slide. Do this by:
- placing one edge of the coverslip on the slide
- use the forceps to lower the other edge onto the slide
- Put the slide on the microscope stage
- Use the lowest power objective lens. Turn the nosepiece to do this
- The end of the objective lens needs to almost touch the slide. Do this by turning the coarse adjustment knob. Look from the side (not through the eyepiece to make sure the slide doesn't break) when doing this.
- Now looking through the eyepiece, turn the coarse adjustment knob in the direction to increase the distance between the objective lens and the slide. Do this until the cells come into focus.
- Slightly rotate the fine adjustment knob to bring the cells into a clear focus and use the high-power objective to look at the cells
- Now rotate the nosepiece to use a higher power objective lens
