Cells Flashcards
Specialised cells
Have adaptations which help them carry out a specific function
Differentiation
The process in which a cell becomes specialised
Sperm cell job
Join with an egg cell in fertilisation
To combine genetic information
Sperm cell adaptations
Contain half genetic information in their nucleus
Long tail to swim to ovum
Packed with mitochondria = energy to swim
Enzymes at top of head to digest outer layer of ovum
Nerve cell function
Send electrical impulses around the body via the axon (long stick bit)
Nerve cell adaptations
Axon insulated by MYELIN to speed up transmission of nerve impulses
Has synapses for impulses to pass from one nerve to next
Dendrites to increase surface area = connect easier
Muscle cell jobs
Can contract for movement
Muscle cell adaptations
Protein fibres to change length (shorten) when contracted = decrease length of cell
Packed with mitochondria to provide energy via respiration
Form muscle tissue together
Root hair cells job
Increase surface area of the root by acting as hairs to absorb water + minerals more effectively
Root hair cell adaptations
Root hair to increase surface area
No chloroplasts because don’t photosynthesise
Xylem cells job
Found in stem as long tubes
Carry water and dissolved minerals from roots to leaves
Xylem cells adaptations
Thick walls w lignin to support the plant
Dead xylem cells because they’re sealed by lignin
Broken down end walls to from the long tube so minerals can flow easily
No internal structure (nucleus, cytoplasm, vacuole) = water and minerals flow easily
Phloem cells job
Carry dissolved sugars up and down the plant
Phloem cells structure
Phloem vessel cell
Sieve plates at end walls with pores
Companion cells connected by pores
Phloem cells adaptations
Vessel cell have no nucleus only limited cytoplasm and sieve plates with pores at end so sugars move through interior
Companion cells with mitochondria to respire for energy = can move the sugars
Eukaryotes
Cells that contain genetic information enclosed in a nucleus
What are the common features of ALL eukaryotes?
Nucleus
Cell membrane
Cytoplasm
Usually larger than prokaryotes
Eukaryotes examples
Animal cells + plant cells
Prokaryotes
Genetic material isn’t enclosed in a nucleus
How is genetic information arranged in a prokaryote?
A single loop of DNA
And maybe small rings called plasmids