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157 Cards in this Set
- Front
- Back
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Endosymbiosis |
A eukaryotic cell consuming a smaller prokaryotic cell which continues to live in the intracellular environment |
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Mitochondria |
An organelle that converts glucose into ATP in the inner mitochondrial matrix: transfer of energy from NADH and FADH2 to ATP results in a proton gradient diffusion of protons drives the synthesis of more ATP protons travel through ATP synthase, a carrier protein, and absorbs the kinetic energy of moving protons |
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Chloroplasts |
is a plastid Green pigmented Turns solar energy into usable chemical energy |
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Aerobic metabolism |
organisms that use oxygen to release energy
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anaerobic metabolism |
organisms that don´t use oxygen to release energy |
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bacteria |
one of three domains contains prokaryotic bacteria has no organelles no nucleoid circular dna |
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archaea |
one of three domains contains prokaryotes distinct from bacteria |
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eukarya |
one of three domains contains eukaryotes usually larger and more complex than prokaryotes has organelles and a nucleus chromosomal dna |
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positive feedback |
when a cell speeds up a process can distabilise cell but may be beneficial as long as its brought back under control |
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negative feedback |
when a cell slows down a process as product concentration increases it has an increased slowing effect in the system |
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central dogma |
DNA (transcription) RNA (translation) Proteins DNA (replication) DNA |
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protein |
are polymers with important structural and metabolic rules made from amino acids functions include support, protection, catalysis, transport, defense, regulation, storage and movement |
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amino acids |
are the monomers from which polymeric proteins are made 20 different amino acids |
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nucleic acids |
DNA macromolecules process genetic info made from pentose sugar, nitrogen, base and a phosphate group A, T, C, G |
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RNA |
single stranded ribose sugar, nitrogen, base and a phosphate group A, U, C, G |
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DNA |
double stranded pentose sugar, nitrogen, base and a phosphate group A, T, C, G |
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enzymes |
catalytic molecules, which may speed up a reaction many roles including defense and signalling regulated by irreversible and reversible inhibitors |
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competitive inhibitor |
block proteins from binding to active site on enzyme |
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non-competitive inhibitor |
does not bind to active site, but changes shape of enzyme and stops protein from binding |
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cell membrane |
selectively permeable often has proteins protruding, which has many functions proteins held there by hydrophobic region made up from phospho bilipid layer lipids move fluidly around lipids may rarely flip to the opposite layer |
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prokaryotes |
include bacteria and archaea most bacteria have a cell wall outside the membrane (archaea do not) has no organelles or nucleus has nucleoid |
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cytoskeleton |
a collective name of all filaments helps in cell division, cell movement, transport, structure and other functions microfilaments intermediate filaments microtubules |
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rough endoplasmic reticulum |
has proteins enter via ribosomes translating from RNA proteins changed into 3D form and tagged protein is put into vesicle, tags resonsible for it being taken to correct place |
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smooth endoplasmic reticulum |
responsible for modification of molecules taken in by cell that may be toxic also is a store for calcium ions which help in muscle movement |
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golgi apparatus |
protein containing vesicles from rough endoplasmic reticulum taken to golgi apparatus it concentrates and packages proteins before they are sent to their extracellular or cellular destination |
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lysosomes |
travel in vesicles to digest molecules brought from outside the cell
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secondary lysosomes |
molecules brought from outside the cell are brought to secondary lysosomes to be digested |
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autophagy |
when a cell automatically breaks down, its components are brought to the lysosome to be digested |
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vacuoles |
occur in many eukaryotic plant cells and fungi
stores toxins and byproducts takes up 90% of cell space catabolism - in seed form the vacuoles contain enzymes that hydralyze proteins as sources of energy |
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microfilaments |
help the entire cell, or part of cell, to move determines and stablises cell shape |
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intermediate filaments |
anchor cell organelles into place in some cells, they radiate away from nucleus resist tension, maintain rigidity |
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microtubules |
thickest part of cytoskeleton form rigid internal skeleton act as a framework which motorproteins can move structures within the cell |
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cilia and flagella |
line cellular membrane cilia are present in the hundreds, either move stiffly to propel a cell, or to move fluid over a stationary cell flagella occur in pairs, they push or pull the cell through its aqueos environment |
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cell wall |
extracellular structure provides support for cell, acts as a barrier to infection contributes to plant form by controlling the direction of cell expansion |
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extracellular matrix |
supports tissue functions in animals holds cells together in tissue contribute to physical properties help minerals passing between different tissues helps orient cell movement during embryonic development |
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cell junctions |
connects adjacent cells three types: tight junctions desomsomes gap junctions |
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cell junctions: tight junctions |
prevents substances from moving through spaces between cells |
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cell junctions: desmosmes |
holds adjacent cells with stable proteins materials move around extracellular matrix provides mechanical stability for tissues that receive physical stress (skin) |
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cell junctions: gap junctions |
they are channels that run through membrane pores of adjacent cells to allow rapid speed of electric current (ie telling heart muscles to beat in unison) |
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cytoplasm |
contains cytosol and everything in the cell important digestive processes occur in cytoplasm of cells |
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ribsomes |
float freely in cytosol found in both eukarotes and prokaryotes translate RNA to proteins |
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three bacteria shapes |
1) rod 2) cokie? (circular) 3) spirila? (spiral) |
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lipids |
hydrophobic tails (non-polar fatty acids) hydrophilic head (charged and associates with water) form cell membranes proteins are contained in cell membranes by their hydrophobic regions connecting to cell membrane lipids may move freely around lipids may rarely flip to opposite layer |
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passive transport (3 kinds) |
allows transport of molecules across membrane must be to lower concentration gradient requires no energy or input substance can diffuse passively across a membrane facilitated diffusion (passive division) includes: 1) channel proteins - transport for specific molecules - open for movement 2) carrier proteins - transport for specific molecules or groups of molecules - molecules bind to move through 3) ion channels - transport of ions |
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active transport (2 kinds) |
moves solutes against their concentration gradients requires use of ATP two types: primary active transport - requires ATP and generally moves molecules across a membrane secondary active transport - Na-K pump consumes 1 ATP and moves 3 sodium out and 2 potassium in |
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endocytosis |
the transport of large molecules into eukaryotes via invagination of cell membrane, for example: lysosomes digest molecule after they are brought into cell |
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exocytosis |
the movement of large molecules out, for example: waste is brought to cell membrane in vesicle exported outside of cell |
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ATP |
formed in mitochondria from glucose
a useable form of energy ATP hydrolysis releases energy to drive endergonic reactions ATP consists of a nitrogen base, sugar and 3 phosphate groups |
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simple diffusion |
passive transport molecule simply travels through cell membrane until equilibrium molecules moves from higher concentrations to lower concentrations concentration gradient has been the driving force behind diffusion |
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facilitated diffusion |
passive transport proteins in cellular membrane facilitate the transport of specific molecules through the membrane until equilibrium may either be: channel proteins (always open) carrier proteins (pulls only specific molecules through) ion channels |
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active transport |
moves solutes ahainst their concentration gradients this requires energy two kinds: primary active transport secondary active transport |
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primary active transport |
involves the hydrolysis of ATP for energy sodium-potassium pump moves sodium Na+ out of the cell and K+ in one molecule of ATP can move 2 K+ and 3 Na+ ions this creates a pressure gradient which means Na+ moves back into the cell and brings a molecule of glucose with it |
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secondary active transport |
does not require energy to function uses force of pressure gradient to fuel transport can move an ion across a plasma membrane against its concentration gradient sodium-potassium pump moves sodium Na+ out of the cell and K+ in one molecule of ATP can move 2 K+ and 3 Na+ ions this creates a pressure gradient which means Na+ moves back into the cell and brings a molecule of glucose with it |
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isotonic |
isotonic means two solutions have same osmotic pressure across a membrane |
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coenzymes |
a coenzyme cant catalyse a reaction on its own, but it can assist ATP and NADH are coenzymes ATP and NADH are reduced (given electrons) and this gives them more energy |
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metabollic pathways |
chemical transformations occur in a series of intermediate reactions that form a metabollic pathway reach reaction is catalysed by specific enzymes each metabollic pathway is controlled by enzymes that can be inhibited or activated |
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catabolism |
catabolism is the release of energy by oxidation involves the breakdown of complex molecules to simplar molecules used to drive chemical reactions catabolic reactions drive anabolic reactions some catabolic pathways can operate in reverse |
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anabolic reactions |
builds up/stores energy (ie in ATP) involves the process which simpler molecules are formed to become more complex ones anabolic reactions usually dont require energy catabolic reactions drive anabolic reactions |
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hydrolysis |
ATP hydrolysis breaks bonds and releases energy, used to drive reactions |
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carbohydrate catabolism |
carbohydrate catabolism in the presence of oxygen releases a large amount of energy (ie respiration) used to harvest energy from food catabolic reactions release large mounts of energy under aerobic conditions creates 35 ATP molecules as opposed to anarobic reactions only get 2 units of ATP |
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carbohydrate catabolism reaction order (aerobic) |
This must occur in the presence of oxygen 1) glycolysis 2) pyruvate 3) pyruvate oxidation 4) citric acid cycle 5) electron transport/ATP synthesis 6) CO2 and H2O 1-2 are in cytoplasm 3-4 are in mitochondrial matrix 5-6 are in inner mitochondrial membrane |
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glycolysis and its inputs |
occurs in cytoplasm the breakdown of glucose releases energy under aerobic conditions glucose is also partially oxidised and some energy is released 6-carbon Glucose -> 2x 3-carbon pyruvate |
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pyruvate oxidation and its inputs |
occurs in mitochondrial matrix pyruvate is oxidised to acetyl coenzyme A and CO2 2x 3-carbon pyruvate -> 2x 2c Acetyl CoA + 2CO2 |
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citric acid cycle and its inputs |
occurs in mitochondrial matrix citric acid cycle oxidises acetyl coenzyme A to CO2 Citric acid cycles completes oxidation of glucose to CO2 2x 2-carbon Acetyl CoA -> 4CO2 |
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perixosomes |
Peroxisomes are small organelles that contain enzymes involved in a variety of metabolic reactions, including several aspects of energy metabolism. |
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desosomes |
A desmosome is a cell structure specialized for cell-to-cell adhesion. A type of junctional complex, they are localized spot-like adhesions randomly arranged on the sides of plasma membranes. Desmosomes help to resist mechanical forces. Desmosomes are also found in muscle tissue where they bind muscle cells to one another. |
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gluconeogenesis |
the new formation of glucose |
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Fermentation |
Occurs in cytoplasm The process of generating ATP under anaerobic conditions It is also the process that allows NAD+ to be regenerated Two pathways are Lactic Acid Fermentation and Alcoholic Fermentation |
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Metabolic pathways |
1) Carbohydrate Catabolism (in the presence of oxygen) 2) Carbohydrate Catabolism (not in the presence of oxygen via Fermentation (lactic acid fermentation/alcoholic fermentation) 3) Catabolic and Anabolic Pathways |
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Carbohydrate Catabolism not in the presence of oxygen |
Carbohydrate catabolism not in the presence of oxygen produces a small amount of oxygen It does so by Fermentation, Lactic Acid and Alcoholic Fermentation Both of these methods only create 2 ATP |
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exergonic reactions |
the release of free energy in ATP, energy is released from P-O bonds |
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cellular respiration |
cellular respiration is the set of metabolic reactions used by cells to harvest energy from food |
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chemiosmosis |
If concentration of H+ is greater on one side of the mitochondrial matrix membrane, the substance will diffuse via travelling through the protein ATP synthase ATP synthase uses potential energy of diffusing H+, and converts it to chemical energy for ATP |
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Photosynthesis |
Anabolic pathways convert light energy into chemical energy as carbohydrates Involves two pathways: 1) light reactions 2) carbon-fixation reactions uses chlorophyll to absorb light energy and the calvin cycle is a set of reactions fuelled by the light |
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Light reactions in chloroplasts |
Light reactions convert light energy into chemical energy as ATP and NADPH (similar to NADH) |
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Carbon-fixation reactions in chloroplasts |
Do not use light Use ATP and NADPH made by light reactions along with CO2 to produce carbohydrates |
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chlorophyll |
When chlorophyll absorbs light it enters an excited state it returns to normal, releasing most of the energy to adjacent chlorophylls Eventually it reaches the reaction center chlorophyll and the reaction center converts the light energy into chemical energy |
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Calvin Cycle |
The Calvin Cycle uses ATP and NADPH generated in light reactions to produce G3P and CO2 It makes carbohydrates from CO2 The Calvin Cycle consists of three processes: 1) Fixation of CO2 2) Reduction and Sugar Production 3) Regeneration of RuBP |
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Mitosis |
Asexual reproduction resulting in genetic consistency Any genetic differences are due to mutations Prokaryotes undergo binary fission Eukaryotes undergo mitosis |
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Meiosis |
Results in genetic diversity Two specialised gamete cells fusing to a zygote |
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Somatic cells |
Body cells that are not specialised for reproduction Are diploid |
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Reproductive signals |
In prokaryotes, reproductive signals may be environmental conditions In eukaryotes, may be related to the function and need of organism |
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DNA segregation |
DNA pulled via spindles Simple in prokaryotes In eukaryotes, it may be more difficult due to nuclear membrane |
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Kinetochores |
Are protein structures that assemble on centromeres (one on each chromatid) |
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Centrosomes |
In cytoplasm the position of centrosomes determine the plane at which the cell divides Only in animal cells, plant cells have microtubule organising centres which play similar roles |
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Spindle |
Forms from the centrosome, extend to middle of cell Three kinds: 2) Astral microtubules - interactions with cell wall to keep poles apart 3) Kinetochore microtubules - attach to chromosomes, Two sister chromatids are pulled apart. |
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Eukaryotic Cell Cycle |
Interphase 1) G1 - cell may stay in this phase for a long time 2) S phase - DNA is replicated 3) G2 synthesis of microtubules M-Phase 1) Mitosis - segregation of chromosomes into two new nuclei Cytokinesis Division of cytoplasm |
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Mitosis Phases |
Mitosis is a small part of a cells life cycle, includes: 1) Prophase - Condensed chromosomes, centrosomes and spindle appear 2) Pro Metaphase - Nuclear Envelope breaks down 3) Metaphase - Chromosomes line up in midline 4) Anaphase - Chromatids separate, microtubules shorten 5) Telophase - Nuclear envelope reforms and spindle breaks down Usually undergoes cytokinesis and returns to G1 |
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evolution |
the change of genetic composition of populations over time derived traits provide evidence of evolutionary relationships |
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taxons and clades |
taxons are any group of species that we can designate with a name divided into clades a clade is a taxon that consists of all evolutionary descendants of a common ancestor |
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homologous features |
shared by two or more species inherited from a common ancestor |
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analogous features |
similar characteristics which evolved separately from different ancestors (convergent evolution) |
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gymnosperms |
Non-flowering seed plants four types: 1) cycads - tropical, earliest diverging clade 2) ginkgos - common in mesozoic, only one species left 3) gnetophytes - similar characteristics to angiosperms 4) conifers - cone-bearing plants |
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angiosperms |
flowering seed plants also bears fruits endosperm (nutritive tissue) undergoes double fertilisation (one sperm fertilises the egg, other fuses with nuclei and will form endosperm) phloem with companion cells |
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flowers of angiosperms |
consists of four whorls: two infertile: sepals (green buds) petals two fertile: stamens (bear microsporangia) carpel (bear megasporangia) perfect flower: male/female parts imperfect flower: male or female parts monoecious: male/female flowers on same plant dioecious: male/female flowers on different plants |
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monocots |
grasses, lilies, orchids, palms - lost their wood |
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eudicots |
vast majority of seed plants |
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phototrophs |
energy source: light carbon source: CO2 |
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photoheterotrophs |
energy source: light carbon source: organic compounds |
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chemoautotrophs |
energy source: light carbon source: CO2 |
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chemoheterotrophs |
energy source: organic compounds carbon source: organic compounds |
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fungi |
absorptive heterotrophy two kinds: saprobes - absorb nutrients from dead matter parasites - absorb nutrients from living hosts body called mycelium spreads filaments called hyphae colonisation on land aided by fungi |
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hyphae |
filaments that spread from a fungus's mycelium hyphae grows by undergoing cell division but not cytokinesis two kinds: 1) coenocytic myceta: no septa 2) hyphae with septa - compartmentalised septa compartmentalises the hyphae |
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A morphological feature shared by all animals |
junctions between cells extracellular matrix molecules |
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multicellular organisms |
single celled organisms came together into complexes, easier to capture prey these cells began to specialise to create organs and organ systems |
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diploblastic animals |
embryos have two cellular layers outter is ectoderm and inner is endoderm |
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triploblastic animals |
triploblastic animals have an outter ectoderm and an inner endoderm also have a third layer, a mesoderm between the two other layers |
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gastrulation |
gastrulation is when the embryo is a ball of cells and forms a cavity called the blastopore |
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protostomes |
in protostomes, the mouth arises from the blastopore first, and the anus forms later |
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deuterostomes |
in deutrostomes, the anus arises from the blastopore first, and the mouth forms later |
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acoelomate animals |
lack an enclosed fluid-filled body cavity the space between the endoderm and the mesoderm is filled with masses of cell, which move by beating cilia |
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pseudocoelomate animals |
have a body cavity called a pseudcoel it is a fluid filled space which suspends internal organs |
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coelomate animals |
the cavity is the coelom, it develops in the mesoderm it is lined with muscular tissue |
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cephalisation |
cephalisation is the concentration of sensory equipment in the head development of central nervous system in the head nervous system extended towards the tail |
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metabolic rate of animals |
measured by the amount of O2 consumed effects different animals uniquely: metabolic rate increases linearly with humans running metabolic rate is parabolic with birds flying metabolic rate is exponential with fish swimming |
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basal metabolic rates |
the standard metabolic conditions when animals are at rest BMR/gram is not uniform across all animals smaller mammals need more food per gram of body weight than larger smaller mammals need smaller amounts of food more often |
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regulators |
regulators are animals that keep their body temp at a certain level regulators exhibit thermoregulation they keep homeostasis - the stability of the internal environment and the mechanisms that maintain stability regulation and homeostasis is expensive external temps do not change internal temp, but it does change the metabolic rate |
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conformers |
conformers are animals whose internal temperature is the same as the external temperature these are poikilotherms or ectotherms most animals exhibit this trait |
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hibernation |
allows animals to reap the benefits of both regulation and confortmity is the term for the winter period to be characterised by conformity |
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phenotypic plasticity |
phenotypes of individual organisms change over time - this is phenotypic plasticity when phenotypes change as a result of the environment, it has acclimatised phenotypic plasticity occurs at the biochemical level, and at the level of tissues/organs natural selection may select for organisms which have the greater phenotypic plasticity |
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sensors and effectors |
sensors detect current level of temperature, etc effectors tissues/organs which change the level of temperature, etc control mechanism uses info from sensors to determine which effectors to activate |
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calorie |
a calorie is the amount of head required to raise the temp of 1 gram of water by 1C 1 calorie = 4.2 joules |
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stores of chemical energy |
chemical energy is stored for future use it is stored in the form of lipids (9kcal/g) stored in the form of glycogen (1kcal/g) although glycogen stores less energy, some tissues use that as an energy source |
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suspension feeders |
collect tiny food particles in great numbers uses filters to collect particles |
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deposit feeders |
animals which eat their way through dirt or sediments and decayed organic materials |
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substrate feeders |
live in their food sources eating their way through the food |
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fluid-feeders |
suck nutrient rich fluid from a living host may be parasitic or mutualist |
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bulk feeders |
most animals are bulk feeders eat large pieces of food that needs to be reduced in size and to aid digestion adaptations include: tentacles, pincers, claws, poisonous fangs, jaws, teeth |
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Ingestionin food processing |
the act of eating cannot use macromolecules in the food mastication - the breaking down of food with teeth |
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Digestions in food processing |
process of breaking down food into molecules small enough for the body to absorb the digestive enzymes can digest ourselves if there is no protective lining |
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absorptionin food processing |
cells take up small molecules such as amino acids and sugars in the digestive system |
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eliminationin food processing |
undigested material and wastes pass out of the digestive system |
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differences in dentition in: carnivores herbivores omnivores |
carnivores: pointed incisors - used to kill, capture and cut prey jagged premolars - help crush/shred food herbivores: broad ridges to grind leaf material incisors modified or absent omnivores: adapted for both meat and vegetation relatively unspecialised dentition |
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differences in digestive tract in: carnivores herbivores omnivores |
carnivores: large, expandable stomachs carnivores may go a long time between meals, and they eat as much as they can when they are able herbivores and omnivores: they have a longer digestive tract allows more time for digestion vegetation is more difficult to digest due to cell walls containing cellulose |
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roles of micro-organisms in digestion |
animals cannot produce enzymes to hydrolyse cellulose this is solved by housing a large population of symbiotic bacteria that can break down cellulose in fermentation chambers micro-organisms have the enzymes required to break down cellulose micro-organisms are given from adult to offspring by getting the babies to eat a special poo from the parents, containing the micro-organisms |
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epithelia |
O2 crosses two simple epithelia to enter the blood CO2 crosses the other direction to be released capillary = epithelium |
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Active transport for O2 |
active transport systems for O2 does not exist non-active diffusion is how O2 crosses small distances bulk transport (travelling in blood) is how O2 travel large distances |
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breathing organs |
lungs - invaginations in body and takes O2 from external environment gills - envaginatons folded out of the body, and takes O2 from external environment has three elements: 1) ventilation system bringing air/water in rapidly 2) thin GEM with large surface area, with blood on one side for rapid diffusion 3) perfusion must be rapid enough for blood to pick up as its being delivered by breathing |
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lungs |
invaginations in body takes O2 from external environment muscles in throat, abdomen expand and contract the lungs perfusion is the blood flow through capillaries perfusion must be rapid mammals uses tidally ventilated lungs birds have rigid lungs with unidirectional airsacs humans use avelar sacs which have numerous alveoli |
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gills |
aquatic animals use gills uses a countercurrent exchange fish ventilate their gills by means of contracting breathing muscles |
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tidal volume |
is the amount of air exhaled and inhaled at rest |
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unicellular vs multicellular organism circulation |
unicellular organisms exchange directly with the environment via diffusion with the cells this is not possible with multicellular organisms multicellular organisms need to use respiratory system to bring all oxygen to all the cells in the body multicellular organisms need three basic components: 1) circulatory fluid 2) set of tubes 3) muscular pump may be open or closed sysmtems |
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open circulatory system |
a lot of insects use an open system the haemoglymph is a fluid which acts as both blood and interstitial fluid haemoglymph bathes the organs directly hearts pump haemoglyph down tubes to a specific part of the body where it leaves the tube into the open space insects, arthropods and some molluscs use this |
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closed circulatory system |
consists of blood confined to vessels, distinct from interstitial fluid the heart pumps blood into a large vessel which branch into smaller vessels materials are exchanged by diffusion between the blood and interstitial fluid bathing the cells |
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fish circulatory system |
simple, closed system two chambered heart -1 ventricle -1 antrium single circuit of blood (pulmonary circuit and systemic circuit joined) uses gill capillaries |
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amphibia circulatory system |
closed system 3 chambered heart -2 antriums -1 ventricle (mixing of oxygen rich and poor blood) two circuits (one pulmonary and one systemic circuit) uses both pulmocutaneous (O2 through lungs and skin) and systemic (through the body) |
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reptile circulatory system |
closed system 3 chambered heart -2 antriums -1 ventricle ventrical partially divided by septum, some mixing of blood 3 circuits: -pulmonary circuit -left systemic circuit -right systemic circuit |
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mammal and bird circulatory system |
closed system 4 chambered heart -2 ventricles (complete seperation by septum) -2 antiums three circuits: -pulmonary circuit -right systemic circuit -left systemic circuit pulmonary artery takes deoxygenised blood to lungs from the right ventricle pulmonary vein brings oxygenised blood to left antrium aorta takes oxygenised blood from the left ventricle to the systemic circuits blood returns to the heart in the superior vena cava (from the upper body) and the inferior vena cava (lower body) |
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heart rate, stroke volume and cardiac output |
heart rate is the number of beats a minute stroke volume the amount of blood pumped in a single contraction cardiac output is the volume of blood pumped into the systemic circulation per minute, depends on heart rate and stroke volume |
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atrioventricular valves semilunar valves |
atrioventricular valves separate the antrium and ventricle semilunar valves control blood flow to the aorta (systemic circuit) and pulmonary artery (lungs) a heart murmur is due to backflow of blood through a defective valve |
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different kinds of blood |
invertebrates with open circulation have haemolymph vertebrates have blood which consists of several kinds of cells suspended in plasma cellular elements occupy 45% volume of the blood plasma is 90% water contains inorganic salts plasma proteins influence blood pH, osmotic pressure and viscosity plasma contains: red blood cells (erythrocytes) -most numerous, red -contains haemoglobin which carries 4 O2 per molecule white blood cells (leukocytes) function as defense by phagocytising bacteria found inside and outside circulatory system |
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hyperosmotic and hypoosmotic flow |
water flows into an area with a higher amount of solutes hypoosmotic side of a membrane has less solutes higher free H2O conc hyperosmotic side of a membrane has more solutes lower free H2O conc |
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Osmoregulation: osmoconformer osmoregulator |
Osmoregulation is the rate of water uptake and loss - must be balanced cells swell and burst if they have too much water shrivel and die if it loses water osmoconformer - isoosmotic to the surroundings (marine animals only) the animals need to always be going to places to suitable for their survival includes marine invertebrates and one marine vertebrate osmoregulator - can regulate and live in environments which may not suit them regulators take water in hyperosmotically and discharging hypoosmotically includes vertebrates |
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osmoregulation: marine fish |
marine fish constantly lose water through their skin and gills to balance this, they drink large amounts of sea water and excretes ions by active transport into gills produces very little urine |
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osmoregulation: freshwater fish |
constantly gain water through osmosis lose salt by diffusion to maintain balance, they excrete large amounts of very dilute urine they also have active uptake of salts from their environment |
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osmoregulation: terrestrial organisms |
desiccation (water loss to environment) is the biggest regulatory problem adaptations help reduce water loss are key to survival on land most have body coverings to help prevent dehydration being nocturnal reduces evaporative water loss |
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nitrogenous wastes |
1) ammonia -very soluble - can be tolerated only in low concs. -these animals need to drink lots of water -common for aquatic species -ammonia kills cells on contact 2) urea -excreted by mammals, amphibians and some fish -produced in liver, taken to kidneys x100, 000 less toxic than ammonia can be stored/transported safetly requires much less water but more energy 3) uric acid -excreted by repitles, birds and insects -insoluble - won't mix with water -excreted as semi-solid paste with very little water loss -require more energy than other two kinds |
