Yr 10 mocks - Biology

Cell membrane

protects cells and transports things in and out of the cell

Nucleus

controls the activities of the cell and contains chromosomes

Mitochondria

Where most energy is released through respiration

Ribosomes

Tiny structures where protein synthesis occurs

Cell wall

maintains cells shape and is made of celluose

Chloroplasts

Trap light energy used for making sugars by photosynthesis

Vacuole

Large cavity filled with cell sap

Cytoslpasm

where most chemical reactions take place

What is a prokaryotic cell?

a simple cell that lacks a nucleus and other organelles

What is a eukaryotic cells

complex cells that contains a nucleus and other organelles

Differences between eukaryotic and prokaryotic cells

prokaryotic contains dna outside the nucleus but eukaryotic contains dna inside the nucleus

eukaryotic cells are bigger than prokaryotic cells

How to use a microscope in 6 steps

1. take a glass slide and place your specimen on it

2. Add a drop of water or stain to your specimen

3. Place the cover slip on your slide

4. Place your slide on the stage in the lowest magnification object lens

5. Look through the eye piece lens and focus on the specimen using the coarse focussing wheel

6. change the objective lens for a higher magnification and refocus

Why are electron microscopes used in biology?

Have a higher resolution and magnification than light microscopes but are more expensive

Specialised cells

cells that have been differentiated to carry out specific functions

for example

red blood cells -biconcave disk increases surface area so more oxygen can be carried

root hair cells - large surface area increases rate or absorption or water and minerals

What are tissues, organs and organ systems made from?

Tissues - a group of specialised cells

Organs - tissues that work together to do a particular function

Organ systems - organs that perform particular functions

Precautions to take when growing microbes

Boil agar - kills bacteria

Flame inoculating loop - sterilises it

Tape down the lids of the petri dish - stops bacteria in air from contaminating the plate

Incubate at 25 degrees - stops human pathogens from frowning

Store upside down - stops condensation dripping and disturbing microbe growth

Chromosomes key facts

Found in the nucleus of eukaryotes

Made out of DNA that can be separated into genes that determine our characteristics