Bio

Created by

Aoife Bennett

Cards (51)

light microscope 
uses light to form images
living samples viewed
relitaveluy cheap
low magnification
low resolution
electron microscope 
uses beams of electrons to form images
samples cannot be living
expensive
high magnification
high resolution
specialised cells 
Cells that are adapted to carry out a particular function
Sperm cell adaptations 
Long tails, many mitochondria for respiration to swim to ovum
red blood cell adaptations 
Contain haemoglobin which binds oxygen, no nucleus (more space for oxygen), biconcave-large SA
Muscle cell adaptations 
Special proteins that contract, many mitochondria to release energy from respiration
Nerve cell adaptations 
Long axons carry impulses, myelin insulates and speeds up to increase transmission speed, synapse allow impulses to move,
Root hair cell adaptations 
long projection speeds up absorption of water and mineral ions, lots of mitochondria
Palisade cell adaptations 
- lots of chloroplasts containing chlorophyll to absorb light energy
- located at the top surface of the leaf where it can absorb the most light energy
Diffusion definition 
Spreading of molecules from an area of higher concentration to an area of lower concentration.
Osmosis definition 
diffusion of dilute water to concentrated water across a selectively permeable membrane
active transport definition 
the movement of ions or molecules into a region of higher concentration, assisted by enzymes and requiring energy.
Factors that affect the rate of diffusion
The concentration gradient, The Temperature, The Surface Area Of the membrane
adaptations for exchanging substances (diffusion) 
villi in small intestine (absorbing nutrients), alveoli in the lungs (gas exchange), fish gills (gas exchange), root hair cells (water and mineral uptake)
cell cycle 
series of events that cells go through as they grow and divide
cell cycle stage 1 
DNA replication and production of new cell organelles
cell cycle stage 2
(mitosis) the nucleus divides
cell cycle stage 3
cytoplasm and cell membranes divide to form 2 identical daughter cells
stem cells 
undifferentiated cells that can develop into different types of cells
adult stem cells are found in
bone marrow
bone marrow stem cells can differentiate into
blood cells
Advantages of adult stem cells
fewer ethical issues
relatively safe donors recover quickly
embryonic stem cells are found 
In early human embryos
embryonic stem cells differentiate into
any type of specialised cell
Advantages of embryonic stem cells
Can form any cell
may be possible to grow replacement organs
no donor needed as usually obtained from spare embryos
disadvantages of embryonic stem cells 
Ethical considerations such as potential loss of life or harm to embryo, less easily obtainable than bone marrow stem cells, risk of rejection
plant meristems are found in
the roots and shoots of plants
meristems can differentiate into 
any cell type
Advantages of meristems 
rare species of plants can be cloned to prevent extinction
fast and low cost production
plants with desirable characteristics can be cloned
disadvantages of meristems 
risk whole crop being destroyed due to plants that are cloned being identical
5 levels in organisation in living organisms 
cells
tissues
organs
organ system
organisms
digestive system
Lungs 
air into body through nose or mouth
down trachea
into bronchi
through bronchioles
into alveoli
oxygen the diffuses into the blood
Artery function 
carry blood away from the heart
Artery structure 
- Thick wall (high blood pressure/oxygenated blood)
- Elastic walls
- Narrow lumen
vein function 
carry blood to the heart
Vein structure 
- Thin wall (low blood pressure/deoxygenated blood)
- Valves to prevent backflow
- Wide lumen
capillary function 
carries blood to tissues and cells, connects arteries and veins.
capillary structure 
one cell thick endothelium. allows rapid diffusion.
narrow lumen
the heart structure