diversity in animal cells 2.6 Flashcards
(48 cards)
what is differentiation
the process by which stem cells become specialised into different types of cells
what do multicellular organisms start life as
as a single undifferentiated cell, called a zygote
whats the genome
all the genetic material in an individual
how do cells differentiate
by turning off certain genes and turning others on
specialised animal cell: what do erythrocytes do
carry oxygen from the lungs to respiring cells
specialised animal cell: what do neutrophils do
ingest invading pathogens
how are erythrocytes adapted
- large sa to vol ratio
- flexible, a well developed cytoskeleton allows them to change shape
- no nucleus, mitochondria or ER so more haemoglobin molecules within them
what are spermatozoa and how are they specialised
- sperm cell
- many mitochondria for aerobic respiration
- ATP provides energy for the tail
- long and thin
- once it reaches the ovum, the enzymes are released at the acrosome (specialised lysosome)
- head of sperm contains haploid male gamete
what are epithelial cells and how are they specialised
- lining tissue
- makes up wall of alveoli and capillaries
- lines intestines
- squamous epithelial cells= flattened in shape
- cilia can be present
what are palisade cells and how are they specialised
- within leaves
- pack together closely but co2 can still diffuse in
- large vacuole so chloroplasts at periphery so co2 can diffuse efficiently
- contain many chloroplasts
- contain cytoskeleton threads and motor proteins for movement of chloroplasts
what are guard cells and how are they specialised
- a pair
-dont carry out photosynthesis
>light energy is used to produce ATP
> the ATP actively transports potassium ions lowering water potential
>water now enters guard cells via osmosis
> guard cells swell and the stomata (opening) enlarges
>air enters and gas exchange occurs CO2 diffuses in
>O2 produced leaves the cell through open stomata
what are root hair cells and how are they specialised
- epidermal cells on the outer layer on young plant roots
- high sa for absorption of water and mineral ions- hair like projection
- mineral ions are actively transported into the cell (lowers water potential causing osmosis to occur)
- have special carrier proteins for active transport
- root hair cell also produces ATP
what do xylem and phloem form
- form the vascular tissue of plants
whats a tissue
a group of simmilar cells working together to form a specific function
what are the 4 tissue types in the body
- epithelial or lining tissue
- connective tissues
- muscle tissue
- nervous tissue
what do connective tissues do
hold structures together and provide support e.g blood, bone and cartilage
what does muscle tissue do
made of cells that are specialised to contract and cause movement
what does nervous tissue do
made of cells specialised to conduct electrical impulses
state things about epithelial tissue (animal)
- lines surfaces
- cells are close and form continuous sheets
- no blood vessels- receive nutrients from diffusion
- cilia may be present
- for protection, absorption, filtration, excretion and secretion
state things about connective tissue
- widely distributed in the body
- contains proteins (collagen and elastin) and polysaccharides.
- consists of an extracellular matrix- enables it to withstand forces (e.g weight)
examples: blood, bone, cartilage and skin
state things about muscle tissue
- many blood vessels present
- are fibres
- elongated and contain special organelles called myofilaments allowing muscle tissue to contract
talk about cartilage (as a whole)
-immature cells in cartilage are called chondroblasts ( can divide in mitosis and secret the extracellular matrix)
-once matrix= synthesised, chondroblasts become mature and less active so are now chondrocytes, which maintain the matrix.
there are 3 types of cartilage= hyaline, fibrous and elastic
talk about cartilage: hyaline
- forms the embryonic skeleton
- C- shaped rings keep the trachea open
- found in nose, trachea and on the ends of long bones
- connects ribs to sternum
talk about cartilage: fibrous
-occurs in discs between vertebrae and in the backbone and in the knee joint
