Biology Unit 1.1 Cells

What does resolution mean

Can be used to see very small objects in fine details when the light microscope cannot

How do you make an onion skin cell slide

1. Peel a small piece of onion epidermis from the onion

2. Using forceps place onion onto slide

3. Add a drop of iodine

4. Use forceps to lever the coverslip down over the skin

Why do you add a drop of iodine to the onion skin cell To stain the cells and make parts of the cells more easily seen

Why do you lever the coverslip on top of the skin To avoid trapping air bubbles

What are the parts of an animal cell Cell membrane, cytoplasm, nucleus, nuclear membrane, chromosomes, mitochondria

What is the cell membrane Controls what enters and leaves the cell, selectively permeable

What is the cytoplasm Where chemical reactions take place

What is the nucleus Control centre of the cell. Contains the genetic information

What is the nucleus membrane Membrane surrounding the nucleus

What is the chromosome Generic information is contained on thread like structures found within the nucleus

What is the mitochondria Where aerobic respiration takes place and energy release. Found in the cytoplasm

What is the cellulose cell wall Immediately outside the cell membrane and provides support. Calcium Pectate helps cement cell walls together.

What is essential in making cell walls Calcium

What is the large permanent vacuole Contains cell sap. When full Pushes cell membrane against cell wall making the cell rigid and providing support

What is the chloroplast Found in the cytoplasm. Contains chlorophyll which is used in photosynthesis. Only found in the greeen parts of the plant

Wha us essential in chlorophyll production Magnesium

What is in a plant cell Cell membrane cytoplasm chloroplast nuclear membrane nucleus permanent vacuole cell wall

What do bacterial cells contain Loop of DNA, Plasmids ( circular rings of DNA), and non-cellulose cell wall

What do a plant and bacterial cell have in common Both contain DNA

both contain a cytoplasm

What are two differences between plant snd bacterial cells Plant cells have a mitochondria and chloroplasts, bacterial cells have neither

Bacterial cells do not gave a nucleus, plant cells do

Define stem cells Unspecialised cell which divides by mitosis and later becomes specialised

In animals what is one source if adult stem cells Bone marrow

What are differences between adult stem cells and embryonic stem cells Embryonic stem cells can differentiate into any cell in the body

Adult stem cells can only differentiate into red and white blood cells

In plants where can stem cells be found Apices or meristems

What can plant stem cells be used for Cloning such as Tissue culture and grafts producing lots of genetically identical plants very quickly

What are differences between plant stem cells and animals stem cells Plants retain the ability to re differentiate, human stem cells cannot re differentiate

How can embryonic stem cells be used in medicine Embryonic stem cells could be used to treat spinal injuries or grow new organs for transplants

How can adult stem cells be used in medicine Treating blood cancers like leukaemia

What are the risks of using adult stem cells in medicine In pre-treatment using radiotherapy which destroys the immune system

Viruses or diseases could be transferred

Formation of Tumors

How can these risks with adult stem cells in medicine be avoided Stem cells can be removed form the patients bone marrow, then it is a perfect match and they don't have to find a donor

What are side effects of radiotherapy Pre treatments kill cancer cells but also kill healthy cells meaning patients have a reduced immunity, side effects such as tumours, nausea, tiredness and hair loss

What is diffusion The move tan of a substance from where it is in high concentration to where the concentration is lower

What are the three factors tha affect the rate of diffusion 1. The concentration gradient

2. Temperature

3. Large surface area

How does the concentration gradient affect the rate of diffusion As the concentration increases the rate of of diffusion increases

How does temperature affect the rate of diffusion High temperature increases the kinetic energy of the molecules making them move faster and so increasing the rate of diffusion

Does diffusion use energy No

Explain an example of diffusion in humans Oxygen dissolves into the lining of the alveoli and into the red blood cells. Carbon dioxide leaves the blood plasma and moves into the alveoli

Define tissue Similar cells grouped together

What is an organ Made up of several types of tissue

Wha are the main organs in plants Root, stem and leaf

What is an organ system Organs that operate together to carry out a particular function

What is an organism A group of organ systems goruped together ina complex animal like a human

Why do large animals need need specialised organs They have a small surface area to volume ratio, cells are too far away from the surface so diffusion isn't fast enough so transport systems are needed