Topic 1 - Key concepts in biology Flashcards
what are all living things made up of?
cells
what are eukaryotic cells like
complex and includes all plant and animal cells
define eukaryote
organism that are made up of eukaryotic cells
what are prokaryotic cells like
smaller and simpler e.g. bacteria
define prokaryote
is a prokaryotic cell (it is a single-celled organism)
define cytoplasm
jelly-like liquid that fills cell and contain enzymes where most of the cell’s reaction takes place
define cell membrane
- surrounds all cells and are made of lipids
- very thin, flexible and partially permeable
- controls what can enter and leave the cell
define nucleus
- contains genetic material DNA
- controls cell’s activities by making enzymes and other proteins
define mitochondria
- small sausage shaped organelles which contain enzymes for aerobic respiration
- where aerobic respiration takes place
define flagellum
- long protein strand that can rotate
define vacuole
- large membrane sac containing dilute mineral solutions called cell sap
- keeps plant cell firm or turgid
define cholorplast
- contains green chlorophyll to absorb light energy
- where photosynthesis takes place
define chromosomal DNA
- circular DNA within cytoplasm not within the nucleus
- controls the cell
define plasmid DNA
- small loops of extra DNA that contains genes
- offers resistance to certain drugs
define cell wall
- strong, rigid wall made of cellulose in plants
- fully permeable
- supports the cell and strengthens it
define ribosomes
- small and lots of them
- place where proteins are made through translation
define specialised cells
made through a process called differentiation
define stem cells
cells that have the ability to differentiate into specific cell types
define magnification
how big an image is compared to the object size
define resolution
smallest separation at which two separate objects can be distinguished or resolved
what are the 2 types of microscopes?
light microscope
electron microscope
what are the limitations of light microscopes?
- lower resolution
- lower magnification
what are the benefits of light microscopes?
- easier
- cheaper
- images can be viewed in colour
what are the benefits of an electron microscope?
- higher resolution
- higher magnification
what are the limitations of an electron microscope?
- very large
- cannot view live samples
- images are viewed in black and white
- expensive
what are the adaptations of red blood cells?
- large surface area
- no nucleus
- contains haemoglobin
- biconcave disc shape