study notes (basics) Flashcards
(35 cards)
1
Q
what is the cell theory / concept
A
- fundamental (structural and functional) units of life
- all organisms composed of cells, smallest living things
- arise from pre-existing cells, ability to differentiate
2
Q
what are the biological scales of life
A
- ecosystems, communities, populations, individual organisms, cells, molecules
3
Q
how is life maintained
A
- energy (tendency towards disorder / chaos)
- storage of information through significant organisation (adaptations, progression, genes)
4
Q
what is the definition of living
A
- highly organised, homeostatic, reproduction, grow, develop and evolve, demonstrate metabolism / transform energy (chemical reactions) and respond to stimuli (movement)
- viruses: not on this system of classification because they are considered non living because they can only carry out these functions once they are in a host cell
5
Q
what is a cell
A
- single unit, enclosed by a plasma membrane, can be unicellular (bacteria) or multicellular (tissues, organs, systems)
6
Q
what is a prokaryote / its characteristics
A
- first cells to ever inhabit earth
- single celled (bacteria), lack organelles
- cell membrane: phospholipid bilayer, semi-permeable, fluid mosaic, proteins embedded
- cell wall: responsible for various shapes
- flagella / pili: ability to swim and form a colony
- nucleoid: no true nucleus, circular chromosomes, transcription and translation are coupled
- cytoplasm: gelatinous helix, chemical reactions, cytosol (semi-fluid matrix)
- ribosomes: free floating in cytoplasm
7
Q
how does prokaryote growth / genetic recombination occur
A
- binary fission: chromosome replication, cell divides and offspring is identical to the single parent
- recombination: without sex, rearrangement of genetic material in an organism, 3;
1. transformation: cells pick up genes from the environment
2. conjugation: direct transfer of genes fromm one cell (donor) to another (receiver),
3. transduction: genes are transferred between cells by viruses - mutation / recombination: promotes genetic diversity, leads to adaptation (advantageous, deleterious or neutral)
8
Q
what is a eukaryote / its characteristics
A
- more complicated, most organelles, true nucleus
- nucleus: genetic information (DNA, linear chromosomes), controls shape / activity through protein synthesis, exports RNA via nuclear pores
- nuclear envelope: double membrane, nuclear pores, regulate passage
- nucleolus: ribosomal RNA synthesis
9
Q
what is a cell membrane
A
- phospholipid bilayer (lipid soluble substances)
- fluid mosaic
- regulates passage of materials (secretion / absorption)
- proteins embedded
- interacts with environment
- tight / occluding: connect membranes of adjacent cells, membranes ‘fused’ by protein bands, impermeable (prevent leakage)
- desmosomes / anchoring: bind adjacent cells (molecular velcro), internal tension reducing network
- gap junctions: communication, chemical signalling, intercellular communication, membranes held apart (contrast tight junctions), can open / close
- transporters / channels: communication, allow movement of ions and larger molecules, influence survival / function / movement, binding of hormones / enzymes
10
Q
what is cytoplasm
A
- gelatinous helix that surrounds the nucleus
- membrane bound organelles suspended, chemical reactions, cytosol (semi-fluid matrix)
11
Q
what are vesicles
A
- storage and transport
12
Q
what are ribosomes
A
- protein synthesis, interchangeable (adjust numbers), free / attached, rRNA + proteins
13
Q
what are lysosomes / peroxisomes
A
- digestive macromolecules / detoxification, recycling
14
Q
what is a cell wall
A
- structural support, withstand gravity, made up of cellulose fibril (structural polysaccharide), xylem (conducts water around plant)
15
Q
what is a central vacuole
A
- large fluid filled compartment
- creates internal pressure (turgidity = swelling / hydration, flaccid = dehydrated), storage and waste breakdown
16
Q
what are chloroplasts
A
- contains chlorophyll, involved in photosynthesis (metabolism of plants)
17
Q
what is the rough ER
A
- ribosomes (protein synthesis), channels move products to targets
- synthesise secretory proteins for export: mRNA + rRNA = ribosomal subunits, combine to make protein, threaded into cisternal space, folds into natural conformation, later transported in vesicles
- growing more membrane: proteins and phospholipids directly added where needed
18
Q
what is the smooth ER
A
- synthesis of lipids, metabolism of carbohydrates
- drug detoxification, muscle contraction (calcium pumping into cisternal space)
19
Q
what is the mitochondria
A
- double membrane (inner wall = membranous cristae) partition matrix in-between (DNA / ribosomes)
- divides independently, site of cellular respiration / metabolism, semi-autonomous
20
Q
what is the cytoskeleton
A
- scaffolding, support, motility, fibrous extensions, centrosome comprising centrioles
- microtubules: cylindrical, tubulin protein units, support / shape cell, move things around, form centrioles
- microfilaments: fine filaments of actin involved in intracellular support and movement, major feature of muscle
- intermediate filament: stable cytoskeletal elements giving mechanical support to the cell
21
Q
what is golgi apparatus
A
- interconnected flattened membranous stacks
- receives, packages, manufactures, sorts, stores and modifies proteins for delivery and export
22
Q
how did eukaryotes evolve
A
- endosboyiont theory
- eukaryotic cells evolved from symbiotic associations with prokaryotes
- mitochondria / chloroplasts (bacterial endosymbionts) were engulfed by prokaryotes and developed to become an organelle in that cell (eukaryote)
- ancestors of mitochondria: oxygen-using non-photosynthetic prokaryotes
- ancestors of chloroplasts: photosynthetic prokaryotes
other organelles formed from invagination (endoplasmic reticulum) and evolved
23
Q
what are viruses / their characteristics
A
- obligate intracellular parasites (require host cell to survive)
- protein molecules, protein coat, non-cellular, genome (RNA or DNA), protein capsid (protection), not living, immobile, metabolically inert, virion structures
- viral envelope: assist virus to deceive host cell to gain entry, similar composition to cell membrane (glycoproteins, envelope fuses with host membrane)
- host range: specific (lock and key), general (mutations, changing ‘locks’), tissue specificity
24
Q
describe cell transport
A
- movement of substances across a cell membrane
- passive: no energy, high conc. to low conc. (simple, facilitated, osmosis)
- active: against gradient, low to high conc., carrier protein
25
what are F plasmids
- small, circular DNA molecule, separate from chromosome, self replicating
- fertility factor: DNA (in plasmid) that allows for conjugation, associated with F plasmid
- sex pillus: between both cells through which the plasmid is transferred from F+ to F- cell
26
what are antibiotics and R plasmids
- derived from bacteria, fungi and protists (single celled)
- inhibit cross-linking of cell wall / protein synthesis
- antibiotic resistant genes: encode proteins that ‘fight off’ antibiotics, genes responsible can be borne on R plasmids, spread from cell to cell, some carry >19 resistant genes due to transposons (‘jumping gene’ which brings resistant genes together)
27
how is disease produced
- sickness due to disruption of host health by invasion of tissues
- pathogens: disease causing organisms / agents
- virulence factors: assist with disease process, help bacteria adhere, invade, prevail, avoid immune defences and damage tissues
28
what are two types of bacterial toxins
- exotoxins: protein secretions, symptoms in absence of bacteria, potent poison (botulism, chloera)
- endotoxins: components of outer membrane, gram negative bacteria (salmonella)
29
what are endospores
- tough, seed-like, develop in bacterial cells, not offspring
- development: division of cell produces one copy with durable wall within the other cell, outer cell disintegrates releasing spore
- metabolically dormant, tolerant to range of extreme conditions
30
why are we metabolically diverse
- allows existence in soil, water, thermal springs, sulphur environments, in / on plants / animals
- essential to support biosphere, economic and industrial importance
- mutualistic bacteria within the human body, pathogenic bacteria
31
describe how tissues develop in an embryo
- three layered embryonic disc is formed, all tissues arise from these three layers
- ectoderm: nervous system as well as skin
- endoderm: epithelial linings of digestive, respiratory and urogenital systems
- mesoderm: forms all other tissues (bones and muscles)
32
what are classifications of tissues
- shape (squamous, cuboidal, columnar)
- number of layers (simple, stratified)
epithelium: outer surface of skin, covers open cavities / walls of internal organs
- structure: avascular, nourished by connective tissue, highly innervated / regenerative capacity, close together
muscle tissues: movement by contraction, myo-filaments (actin and myosin), highly vascularised, many mitochondria, specialised cells
- skeletal: voluntary, stripes, striated, multi nucleated
- smooth: involuntary, walls of hollow organs, long tapered
- cardiac: involuntary, striated / branched cells, uninucleate
connective tissues: most abundant, distribution varies, support / communication, protection, nutrient storage, cells are separated by matrix
- four classes: connective tissue (loose or dense), cartilage (hyaline, elastic and fibrocartilage), bone (compact or spongy) and blood
nervous tissue: specialised to carry electrical signals, highly specialised
- sensory: sense receptors to CNS
- motor: CNS to muscles / glands/ terminal and dendrites
- neuralgia / glial cells: supportive cells (astrocytes, microglial cells, ependymal cells, oligodendrocytes, satellite cells, schwann cells)
33
how is tissue repaired
- replacement with functional tissue
- fibrosis: fibrous connective tissue replaces functional tissue, strong but not flexible or elastic
- high regeneration properties (epithelial, bones, connective)
- moderate capacity (skeletal, cartilage)
- no regeneration properties (nervous / cardiac)
34
differences in tissue repair in animals and plants
A: similar cells and extracellular matrix, organised into structural and functional units
- evolved, specialised in animals (require higher function in order to support higher order organisms)
- junctions: connect cells, function as a single unit
P: dermal (covering / protection), ground (storage, growth, structure, photosynthesis), vascular (transport of photosynthetic products, water)
- middle lamella hold cells together, plasmodesmata are channels that allow exchange
35
how do viruses reproduce (HIV)
1. virion enters cell
2. viral DNA uses host nucleotides and enzymes replicate itself (transcription and translation)
3. viral DNA produce capsid proteins / ‘progeny’ (genomes assemble into new virions -highjacking)
4. new viruses bud from the cell (may be wrapped in membrane)
- retrovirus (HIV): reverse transcriptase (replicates RNA and then creates a DNA double helix)
- viral disease symptoms: cells killed, toxins produced by infected cells and viral envelope can be toxic all lead to disease, extent of damage can depend on the tissue infected
- temporary symptoms: body’s defence against virus
