Topic 3 And 4 Flashcards
What is facilitated diffusion
Movement of particles from areas of high to low conc using proteins
-down a cg
Active transport mechanisms
Endocytosis - movement of large mols into cells thru vesicle formation
Exo- movement of large mols out of cells thru ves formation
Active transport - movement of substances across the membrane of cells directly using atp
what 2 types of proteins are involved in facilitated diffusion?
carrier - particle attaches to protein, protein changes shape and transports the particle across the membrane.
channel - channel proteins are hydrophilic, water soluble ions and molecules can diffuse thru these to the other side of membrane
when will facilitated diffusion take place?
how can water soluble mols pass thru membrane
when the mols are charged or too large to pass thru membrane by simple diffusion
carrier or channel proteins
Define osmosis
Net movement of solvent water molecules from a region of higher water potential to a region of lower water potential thru a partially permeable membrane
Why does pure water have the highest water potential ?
If you dissolve a solute in water why does the water potential lower?
All water molecules have the ability to cross the membrane
The solute bonds with the water mols, reducing the waters ability to move
The lower the water potential the more ? The number becomes
Negative
Hypotonic
Isotonic
Hypertonic
Lower conc of solutes compared to inside the cell
Conc of solutes in the solution is thr same as in the cells
Higher conc of solutes compared to inside of the cell
What is biodiversity
Taxonomy
variety of living organisms and their genetic differences
The science of describing , classifying and naming living things
Analogous features
Similar features but different biological origin
Morphology
Study of the form and structure of an organism
Morphological species concept
Based on an organisms appearence
A - u can tell by looking at an organism what it is
D - males and female may look so different but could be the same species , sexual dismorphism
Reproductive / biological species concept this the most accepted
A group of organisms with similar characteristics which interbreed to produce fertile offspring .
d - all organisms in a species cant attempt to itpfo bc they dont all live in the same area
Ecological species model
Based on ecological niche occupied by an organism
Mate recognition species model
Based on fertilisation systems including mating behaviour
Genetic species model
Based on molecular phylogeny , the degree of DNA difference needed to make separate species has not been decided
Evolutionary species model
Based on evolutionary rs, members of a species have a shared evolution and are evolving tog
Limitations of species concepts
- Finding the evidence - many living species have never been seen mating , time consuming and pricey to set up a breeding programme
- Plants of closely related species often inbreed and produce fertile hybrids
- Many organisms don’t sexually reproduce eg bacteria
what happens when a plant cell is placed in a hypotonic solution?
water moves in by osmosis , cell swells, cytoplasm and vacuole enlarge untill they press on the cell wall. inward pressure from cell wall increases till no more h20 mols can move in . cell is at TURGO
what happens when a plant cell is placed in a hypertonic solution?
water leaves cell by osmosis, vacuole and protoplasm shrinks and pulls away from cell wall. this is plasmolysis.
what happens when a plant cell is placed in an isotonic solution?
incipient plasymolysis occurs when the cell membrane starts to pull away from the cell wall
What is turgor pressure and osmotic water potential
Tp- measure of inward pressure exerted by plant cell wall. Opposes entry of water by osmosis
Omw- the potential of water to move across a partially permeable membrane . The greater the conc of solutes the lower the osmotic potential bc there are less water mols to pass thru the membrane .
What happens when the turgor pressure and osmotic potential are equal
The cell is at full turgor and the water potential of the cell is at zero
Water potential = turgor pressure + osmotic potential
How does active transport work?
A molecule attaches to protein carrier of specific shape.
Carrier protein changes shape allowing the mols into the cell across the membrane
Protin carrier returns back to og shape
When the protein carrier changes shape this requires …
Energy which is provided thru the hydrolysis of atp
What is exocytosis and endocytosis used for
Pinocytosis?
The transport of larger mols in and out cells
Cells take tiny amounts kg extra cellular fluids into vesicles
What is active transport
Movement of molecules against a concentration gradient. Or electrochemical
Gradient . Low to high
Describe how dna sequencing and bioinformatics can be used to distinguish between species and determine evolutionary rs
DNA sequencing - process by which the base sequences of all of / part of a genome is worked out
DNA profiling/bioin - where non coding regions of dna are analysed to identify patterns
What 3 ways do scientists share answers test their work
Scientific articles , (magazines scientists publish articles describing their work )
Peer review. (Other scientists check and review the work to make sure the scientific evidence is valid
Conferences (meetings scientists attend so they can discuss each others work)
How does electrophoresis work
- Restriction enzyme cuts DNA Into fragments
- Agar and electric current separates dna
- Dna fragments move different distances based on size
- UV light used to see bands
- Species with most similar bands are more closely related to common ancestor
Eukarya
Archaea
Bacteria
- Nucleus and unused sections
- No nucleus but unused sections
- No nucleus and no unused sections
What are the 3 domains ? This is recent new study
- Bacteria and archaea are prokaryotic
And eukarya is eukaryotic
What 3 methods can be used to distinguish between species ams determine evolutionary rs
- Gel electrophoresis
- Dna profiling / bioinformatics
- Base sequencing
What evidence led to the three domain model of classification replacing the 5 kingdom model
Techniques of molecular phylogeny was used like bioinformatics
Which found similarities between archaea and bacteria like membrane structure
Why do organisms need specialised gas exchange surfaces as they increase in size ?
Diffusion distance is greater, metabolic rate is higher and sa:v ratio is smaller
Ficks law shows factors effecting the rate of diffusion
R of d is proportional to SA x conc difference
——————————-
Membrane thickness
Where does gas exchange occur
Alveoli , o2 is inhaled and moves from alveoli to the capillaries via diffusion.
And the co2 diffuses out the blood and is exhaled
2 advantages of alveoli
Large surface area
Short diffusion distance: cap and alv one cell thick
Steep conc gradient , conc gradient is maintained by blood flow
-moist to allow gases to dissolve
structure answer for a q ab evolution?
1, genetic variation thru mutations
2. environmental change adding selection pressure
3. natural selection
4, inherticance
5. evolution
Higher alllele frequency increases for birds with pointy beaks etc …
evolution?
ns?
a change in the characteristics of a species over time
certain organisms of a species r most likely to survive and reproduce than other membes of that species due to certain gv
whats a niche?
how can organisms occupy niches according to their physiological , behavioural and anatomical adaptations
an organisms role in the community
- adaptation involving the way the body of an organisms works
- adaptations involving instinctive beh making the organsims better adapted for survival
- adaptation involving sturcture and form of an organisms
How are insects adapted for gas exchange
Air enters thru spiracles ( opened and closed by sphincters )
-air moves along tracheae by diffusion
tracheoles (contain large sa) can contain water at the end which makes it hard for diffusion to take place , the water is removed in active insects as lactic acid builds up in the cells which decrease water potential so water moves into cells by osmosis
How can antibiotic resistance happen
What is speciation
Formation of a new species it happens as a result of isolation of parts of a population
How does reporoductive isolation occur
2 populations are reproductively isolated and experience diff conditions/ selection pressures
Over time ns changes the geno and phenotype of the groups
2 reasons for reproductive isolations
Geographical isolation - a physical barrier that separates the population eg lake
Ecological - 2 populations inhabit same region but develop prefence for diff parts of the habitat
What is allopatric speciciation
This type of speciciation takes place when populations are geographically isolated
Adaptive radiation
A species evolves rapidly to fill in the ecological niches
gills in fish are covered by a bony flap called the
gil filaments exist in stacks called
operculum
lamellae
how does gas exchange occur in fish
- oxygen rich water enters mouth
- passes thru gills
- in the gills oxygen diffuses from water into blood
4, c02 diffuses from blood into water - water passes out opercular opening
how are gill lamellae adapted for gas exchange
-they have a large surface area to volume ratio for diffusion
-thin for shorter diffusion distance
-countercurrent to maintain conc gradient
-continuous movement of water over gills keeps them spread out to increase the s.a
how does the counter current exchange system work
blood leaving gills flows in opposite direction to the water ensuring sufficient gas exchange
-blood in gills and water flow in diff directions which allow maitain conc gradient
How are leaves adapted for gas exchange
Where does gas exchange take place In a plant
- Large sa thru spongey mesophyll cells, leaves, and irregular shapes of cells
- Air sacs and leaves by diffusion
The process of gas exchange : in plants
Co2 diffuses into stomata for photosynthesis , 02 produced diffuses out the stomata
The waxy cuticle of a plant
The lower epidermis
Prevents water loss
Contains guard cells,,s which open and shut the stomata , day = opens night = closed
What are lencitels
Areas of loosely arranged cells which act as pores allowing gas exchange to take place in woody plants
Symptric speciation
Speciciation that takes place between pop of species living in the same place. They r reproductively isolated due to mechanical , behavioural or seasonal mechanisms
Mechanical isolation
Mutation occurs which changes genitalia of animals so they can only mate with some members of the group
Behavioural
Changes in mating Pattern so some individuals don’t recognise others as potential mates , eg mutation changing colour of animal
Seasonal isolation
The timing of flowing In some parts of pop drift away from norms for the group
How can hospitals prevent bacteria strains increasing
Don’t give antibiotics if it’s not necessary, encourage patients to complete ab course
Why is biodiversity important
Water and air of the planet are purified by a wide range of organisms
- plant biod provides the potential for plants to produce chemicals that can be used in medicine
Biodiversity can be measured in what 2 ways
Species richness - no of diff species in a habitat
Relative abundance - no of indivs per species
What is Simpsons species diversity index
Part 1
N(N-1) / Sum of n(n-1)
Simpsons species diversity index
d = species diversity index
N = total no. Organisms
n = no. Of organisms of each species
Biodiversity isn’t just based on physical characteristics of organisms it’s also.. THIS IS THE DEFINITION OF GENETIC DIVERSITY
looked at genetic lvl by looking at the variety of alleles in the gene pool of a pop,
Allele freq
Freq in which a particular allele appears in a population
What are some ethical reasons for maintaining biodiversity
human activities can cause mass extinction of species thru climate change and this interference with biod is unethical
What are ecosystem services and give 2 examples
Services provided by the natural environment which are beneficial, to ppl
Provisioning services - ecosystems provide us with provisions we need eg food and medicine , more biodi =. More provisions
Regulating - ecosystem processes help regulate the environment
Supporting services
Cultural
Biodiverse ecosystems provide support for other ecosys services we need
A biodiverse echo system is important to human health and well being
what is conservation
protecting a changing environment
ex-situ conservation?
in-situ conservation?
conserv outside an organisms habitat
conserv inside an organisms habitat
types of exu - situ in animals
disasv -
captive breeding programmes - endangered species r bred to increase gd and pop size
reintroduction programme - release animals bred in captivity into their natural habitats
not enough spaces and resources in zoos for the endangered species , diffucult to provide the right conditions for breeding, expensive and time consuming
types of exu - situ in plants
seed banks - store a large number of seeds to conserve gv and prevent plant species going extinct
types of in -situ conservation
disadv -
education programmes - educating ppl on importance of bd
national parks - aim to conserve habitats and biod
ppl argue the land used can be used for better things like building a hospital
