L2: Cells, tissues & homeostasis Flashcards
identify the organisation of living things
atoms -> molecule -> macromolecule -> organelle -> cell -> tissue -> organ -> organ system -> organism
cells are divided into two categories (identify & describe)
prokaryotes (bacteria & archaea)
- simple, DNA floating around
eukaryotes (plants, fungi & animals)
- complex, DNA in a nucleus
identify & describe the components of a eukaryote cell
plasma membrane (semipermeable casing)
cytoplasm & cytoskeleton (provide structure)
nucleus (holds DNA)
endomembrane system (surround nucleus, internal cell communication)
mitochondria (produces energy)
what is apart of the endomembrane system?
endoplasmic reticulum
golgi complex
lysosomes
mitochondria contains DNA that is only passed through the . . . line
maternal
what are cilia, flagella, & pseudopodia?
specialised features in a eukaryote cell for cell locomotion
what part of eukaryote cells aid in absorption of ingested food water & how?
microvilli - increased surface area
identify the part in a eukaryote cell that regulates selective movements of substances
the tight junction
what is the purpose of desmosomes in a eukaryote cell?
mediates cell-to-cell contact
identify 3 types of endocytosis (cell eating)
phagocytosis
pinocytosis
receptor-mediated endocytosis
describe the process of phagocytosis
occurs in simple animals
membrane of the cell wraps around object, enclosing it in a vesicle. lysome carries enzymes to break down the object
describe the process of pinocytosis
phagocytosis with receptors
molecule interacts with a particular receptor on cell membrane, forming a caveolae around the molecule
what is transcytosis?
the molecule is moved to another part of the cell where it is needed (during pinocytosis)
identify the type of endocytosis that involves the binding of large molecules
receptor-mediated endocytosis
what is mitosis?
a form of cell division, resulting in two identical daughter cells
identify the 4 phases of mitosis
prophase: gathering of chromosomes in nucleus
metaphase: spindles attach to 2 parts of chromosomes
anaphase: separation of spindles
telophase: creation of own nuclei & replicating chromosomes
what is apoptosis?
programmed cell death, allowing cells to turnover.
identify the types of cells in animals
sex cells
skin/epithelial cells
muscle cells
blood cells
nerve cells
fat cells
what are tissues?
groups of cells specialised for a function
describe the function of the 4 types of tissue & name an example for each
connective (bone, blood, cartilage, tendons)
- binds & supports other tissue
nervous (nerves, brain)
- senses stimuli & transmits signals throughout the organism
epithelial (skin, intestinal linings)
- closely joined cells covering the body
muscle
- contract in response to nerve signals
- helps with locomotion
identify the 3 types of muscle tissue & name an example for each
smooth muscle (digestive tract & involuntary body movements)
cardiac muscle (heart contractions)
skeletal muscle or striated (voluntary movements)
how does muscle tissue work?
slides past eachother to contract
attached in antagonistic pairs (contracting/relaxing muscle)
what are the different types of symmetry in animal body plans?
spherical
radial
bilateral
what is the purpose of skeletons?
provides support & locomotion
identify the 3 kinds of skeletons
hydrostatic: no firm base, fluids enclosed in cavity
exoskeleton: protective outer ridge skeleton
endoskeleton: internal bone or cartilage skeleton
what is homeostasis?
self-regulating process of maintaining an internal balance, despite external conditions
what is positive & negative feedback?
negative feedback reduces the stimulus to a stable state
positive feed back amplifies the stimulus
what is acclimatisation?
adjusting to changes in external environment
what is thermoregulation?
the process of maintaining internal temperature within a range tolerable for systems to function
what is endothermic?
generating heat by metabolism
allows animals to be active at greater range of temperatures, but more energetically expensive
what is ectothermic?
gaining heat from external sources
tolerates fluctuating temperatures more
how is heat exchanged between organisms?
radiation (waves)
evaporation (sweating)
convection (water & air)
conduction (direct contact)
provide 5 examples of different adaptations for thermoregulation
insulation reduces heat flow between animal & environment
circulatory adaptations may enhance or constrict blood flow
cooling by evaporative heat loss
behavioural responses
adjusting metabolic heat production (shivering or non shivering thermogenesis)
