diversity in animal cells 2.6 Flashcards
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
talk about cartilage: elastic
-makes up outer ear and the epiglottis
what are the 3 main types of tissue in plants
- epidermal tissue
- vascular tissue
- meristematic tissue
talk about epidermal tissue (plants)
- equivalent to epithelial tissue in animals
- consists of flattered cells the lack chloroplasts ( apart from guard cells)
- form a protective covering over leaves, stems and roots
- form waxy cuticle (reduces water loss)
talk about vascular tissue
- xylem and phloem
> xylem vessels carry water and minerals from roots to all parts of the plant
> phloem sieve tubes transfer the products of photosynthesis, in solution from leaves to par of plants that dont photosynthesise, such as roots, flowers and growing shoots
talk about meristematic tissue
- contains stem cells
- found at the roots and shoot tips and in cambium of vascular bundles
- the cells in meristems have thin walls with little cellulose, no chloroplasts, not a large vacuole and can divide by mitosis and differentiate into other types of cells.
where do new cells arise in plant cells and by what means? how does this occur
at the meristems via mitosis
what cells can differentiate into xylem vessels or phloem sieve tubes or companion cells? how does this occur
cambium cells
how do cambium cells differentiate into xylem vessels
-lignin is deposited to waterproof them, the ends of the cell breaks down so the xylem forms continuous columns with wide lumens to carry water and dissolved minerals
how do cambium cells differentiate into phloem sieve tubes or companion cells
- sieve tubes lose most of their organelles and sieve plated develop between them
- companion cells retain their organelles and continue metabolic functions to provide ATP for active loading of sugars into the sieve tubes
plant organs: what is the function of the leaf
-photosynthesis
plant organs: what is the function of the root
- anchorage in soil
- absorption of mineral ions and water
- storage
plant organs: what is the function of the stem
- support
- holds leaves up so they are exposed to more sunlight
- transportation of water and minerals
- transportation of products of photosynthesis
- storage of products of photosynthesis
plant organs: what is the function of the flower
-sexual reproduction
whats and organ
a collection of tissues working together to carry out the same function
whats and organ system
a number of organs working together to carry out an overall life function
what are stem cells
- undifferentiated cells capable of becoming any type of cell
- described as pluripotent
- able to express all their genes
- can divide by mitosis to provide more cells that can then differentiate into specialised cells for growth and tissue repair.
what are the 4 sources of stem cells
- embryonic stem cells
- umbilical cord blood
- adult stem cells- (found in developed tissues, such as blood, brain, adipose tissue and skin)
- induced pluripotent stem cells (iPS) developed in labs by reprogramming differentiated cells to switch on certain key genes and become undifferentiated
what can stem cells from bone marrow treat
sickle cell anaemia and leukaemia and treating the immune system.
-used to restore the patient blood system
what are the potential uses of stem cells
-bone marrow transplants
-drug research
-developmental biology (how organisms grow and develop)
-repair of damaged tissues or lost tissues
treating neurological diseases( Alzheimer’s and Parkinson’s disease)
what is regenerative medicine
the fact that stem cells can be used to populate a bioscafflod of an organ and then directed to develop and grow into specific organs for transplanting
what are the 4 types of stem cells (pluripotent etc..)
-totipotent- can develop into any cell type including placenta and embryo
-pluripotent- can develop into any type of stem cell apart from embryo or placenta
-multipotent- can develop into a few different types of cell
unipotent- can develop into one type of cell
function of squamous tissue and location in human body
- Acts as surface/ short diffusion pathway
- Alveoli/ cheek lining/blood vessels
function of cilliated tissue and location in human body
- Move/ secrete mucus
- Bronchioles/ bronchi/ trachea/ airways
3 types of muscle tissue
- skeletal (cause bones to move)
- cardiac ( pump blood)
- smooth (propels substances)
