Biology Flashcards
what are the 4 factors that affect the rate of photosythesis
light intensity,temperature,concentration of carbon dioxide,chlorophyll
What does chlorophyll do
absorbs light energy needed for photosynthesis
How do the levels of chlorophyll vary within different plants
disease,enviromental stress,lack of nutrients
Why is temperature not as effective when affecting the rate of photosynthesis
because when the enzymes gain to much energy they denature
How do people artifically create conditions that help affect the rate of potosynthesis
in colder climates if you use greenhouses it traps the suns heat which helps increase the temperature and it helps photosynthesis continue through day and night,it will be harder for pests and pathogens to enter the plants
A parrafin heater releases heat and CO2
What is required to produce amino acids from glucose
Nitrates
T or F The compensation point is lower in shade adapted plants than in plants adapted to sunny conditions.
true
What is the compensation point
The compensation point is the light intensity at which the rate of photosynthesis is equal to the rate of respiration of a plant.
Which parts of the electromagnetic spectrum are absorbed by the chlorophyll molecule and why?
Red and blue parts of the electromagnetic spectrum are absorbed by the chlorophyll molecule.The chlorophyll molecule appears green because this is the part of the spectrum it reflects, absorbing blue and red.
In an investigation on photosynthesis, why did a student add sodium hydrogencarbonate to the water?
The student added sodium hydrogencarbonate to the water because it is a source of carbon dioxide for the pondweed in the investigation.
what could best explain why a student studying bubbles of oxygen given off from pondweed obtained a result of 81 in one experiment, and 9 bubbles in a second experiment?
The student moved the pondweed from a distance of 10 cm away from the light source in the first experiment, to 30 cm away in the second
what best explains why a plant breeder placed open bags containing a fungus around his greenhouse?
The fungi will respire and release carbon dioxide into the greenhouse.
What is the definition of cellular respiration
an exothermic reaction which transfers energy from glucose and is continously occuring in living cells
What are the examples of how organisms use their energy
to build larger molecules from smaller ones,muscular contraction,to maintain body temperature
What is the definition of metabolism
all chemical processes that occur within a living organism in order to maintain life
what are the 2 types of respiration
anaerobic and aerobic
Where is aerobic respiration used
in the mitochondria and it is used with oxygen
What is anaerobic respiration and what is the word equation
it is used when our body can’t supply oxygen like running the word equation is Glucose->lactic acid
What are the 2 reasons our body prefers not to use anaerobic respiration
incomplete breakdown of glucose molecule as there is no oxygen to oxidise it,lactic acid builds up and later it has to be removed
What is the word equation for anaerobic respiration in plants and yeast,what is the word equation called for yeast
Glucose->ethanol+carbon dioxide for yeast this process is called fermentation
What is the scientific definition for respiration
a series of biochemical reactions,controlled by enzymes that releases energy from glucose.The process happens inside the cells cytoplasm and special organelle called the mitochondria
describe the process of respiration
blood cells transport the oxygen around the body,when it reaches the mitochondria the oxygen is absorbed,and the glucose in the blood cells is partially broken down in the cytoplasm before it is absorbed by the mitochondria.Once in the mitochondiron the oxygen and glucose react to form water and carbon dioxide and releases energy in the form ATP
What is variation controlled by?
Genes and the enviroment
What are sperm and egg cells also known as
Haploids
What is fertilisation
when sperm and an egg fuse
What are 2 examples of genetic variation
natural eye colour and gender
What is a mutation
A mutation is a change in a gene or chromosome.
What type of change does the peppered moth show?
Natural selection is the change as the moth with the best camouflage survived
Why is selective breeding used with animals or plants?
Genetic diversity is reduced as only desirable characteristics that will be of benefit will be selected, e.g. good quality meat.
What is genetic engineering?
he genome of one organism is altered by adding a gene from another to create a desirable characteristic.
What are clones?
Genetically identical to the parent cell
How are animals cloned?
Animals are cloned by using embryo transplants and adult cell cloning
What is the process of genetic engenering
you find an organism with a desirable characteristic(a plant with lots of fruit)then you take some of the gene and transfer it to another organism so the other organism develops the same trait
T or F when genetically modifing a specie you are only limited to that particular specie
false you can modify other species with it
How has bacteria been genetically modified
to produce the hormone insulin this helps us treat diabetes
How does gene therapy work
if someone or something has faulty genes gene therapy will give a person the healthy version of the gene
What are the problems with gene therapy and what is a possible solution for it
that the faulty gene would be in all of the cells.it is hard to transfer the new cell to every cell in the body the solution would be to transfer the gene at an early stage of development
What are the pros of genetically modified crops
to make them with desirable characteristics(more fruits,resistant to disease)this makes more food for less money,make them produce special nutrients
What are the cons of genetically modified crops
we don’t know how genetically modified crops will affect our health,they could outcompete different plants which would change the entire ecosystem
When genetically modifying things how do we transfer the genes from one place to another
1.Find the gene we want and cut the part of DNA we want of it to isolate it we do this by using enzymes
2.Insert the gene into a vector(a virus or a bacteria plasmid
3.Introduce the vector to any organism we want to have the gene,then it will take in the vector and start producing the protein it is coded for
Why is studying fossils important
because most of the things that ever lived are extinct so the only way we can learn about them is looking at what’s left behind of them,we can see how organisms have changed which helps with evidence for evolution
what are the 3 main ways that fossils can be formed
gradual replacement by minerals,casts+impressions,preservation
explain the fossil form of gradual replacement by minerals
things like shells teeth and bones take a really long time to decay so as they decay they are replaced by minerals making them form rock like substances
explain the fossil form of casts+impressions
we get casts when an organism is burried in a soft like way and as it hardens the organism starts to decay and we are left with a gap which was the same size and shape as the organism was.Impressions are things like footprints where organisms leave a mark on the ground
Explain the fossil form of preservation
this is very rare,it is where no decay happens at all,it happens when organisms get stuck in amber or tar pits and because there is no oxygen or moisture no decay can take place
What is 2 reasons for us not knowing how life first developed on earth
early life forms were soft bodied so they decay very quickly,fossils that were formed long ago may have been destroyed since like volcanoes
What are the reasons for species becoming extinct
the enviroment changes to quickly(habitat getting destroyed),human hunting,disease,new species outcompetes them for food,catastrophic event like an asteroid(dinosaurs)
What is variation caused by?
enviromental and genetic factors
which type of variation is human blood groups an example of?
discontinous
According to Darwin’s theory of evolution, how do new species evolve?
By natural selection.
Which individuals are most likely to survive to reproduce?
Those well suited to their environment.
Why might antibiotic resistance develop in populations of bacteria?
Mutations in individual bacteria protect them from the antibiotic, letting them reproduce while others are killed.
Which type of variation can be passed on to the next generation?
Genetic variation can be passed on to the next generation.
T or F Some mutation are beneficial
true
What is a mutation?
A random change in the number of chromosomes.
What has provided evidence for evolution?
Fossils
What can happen if a species fails to adapt to environmental changes?
If a species fails to adapt to environmental changes it can become extinct.
What do evolutionary trees show us
relationships between different species or groups
What is the acronym to help us memorize the domains
Dear-Domain
Kate-Kingdom
Please-Phylum
Come-class
Over-Order
For-Family
Great-Genus
Spaghetti-Species
What is the binomial system
this system of naming consists of two words for each organism. The first word is the name of the genus, while the second word is the species.
Instead of the binomial system what do scientists use now and who created it
they now use the “three domain system”created by Carl woese
Describe archae
archae(primitive bacteria) are often found in conditions like hot springs
Describe true bacteria
they live in the human digestive system
Describe eukaryota
these include animals,plants and fungi it also includes protists such as amobea
What are the three domains
archea,true bacteria and eukaryota
What do scientists use to make evolutionary trees
with classification data(like DNA)
How do scientists make evolutionary trees on extinct organisms
by using fossils
What is the function of leafs and how does it help photosynthesis with water
they are the site of photosynthesis,they make water as the water from the soil and is transported through the roots and xylem,the carbon dioxide diffuses into the leaf via the air through the holes called stomata then it goes up the leaf and enters the spongey mesophyll
Where is the stomata located
in the lower eperdermis
How does the carbon dioxide work in a leaf
the carbon dioxide diffuses into the leaf via the air through the holes called stomata then it goes up the leaf and enters the spongey mesophyll which has a lot of gaps so then the carbon dixoide can diffuse into the palisade mesophyll(this is where photosynthesis happens as they are packed with chloroplasts
What does the plant do with the glucose produced from photosynthesis
it goes through a tube(phoem)
How is the upper epidermis adapted to benefit photosynthesis
they are almost transparent so it allows the sunlight to pass through it to get to the palisade mesophyll underneath
Explain why water loss it a leafs biggest problem and then explain how the plant is adapted to it
water is carried in through the xylem but it is easily lost,on the upper epidermis it has a waxy cuticle(thin water layer of lipids)and the water can’t get through it,on the bottom the stomata is open for as little time as possible
How are guard cells adapted for photosynthesis
when they are turgid the gap is very big to allow for carbon dioxide,when the plant is short of water they will lose water so they become flaccid which makes them close which prevents water loss,they also close at night time because photosynthesis isn’t taking place
What is a meristem tissue,where are they found and what do they do
the plant form of stem cells,they are found on the tips of plant roots and they differentiate so that the plant can grow
Which tissue layer of the leaf carries out most of the light absorption for photosynthesis?
Palisade tissue
What is the name of the process by which carbon dioxide and oxygen enter and leave the leaf?
diffusion
Which of these substances is carried in the phloem vessels of the plant?
sucrose
T or F Tough walls containing lignin is a feature of the xylem vessel
true
What is the loss of water vapour through the stomata called?
Transpiration
What does transpiraton do
transpiration cools the leaf by the evaporation of water from the spongy mesophyll cells.
What is the name of the process in which water moves into the root hair cell?
osmosis
How are root hair cells adapted to maximise water absorption?
Root hair cells are long and thin to give a large surface area for maximum water absorption.
What two things are measured in a potometer to give an estimate of the rate of transpiration?
The distance the bubble travelled and the time it took
How many pairs of chromosomes do human cells contain in the nucleus
23
How do cells divide
by mitosis
How does mitosis work
one cell is copied into 2 identical cells
In what cell are chromosomes not paired
in gametes
How is meiosis different to mitosis
meiosis prouduces non-identical cells(every sperm and egg cell are different)
T or F animals and flowering plants carry out sexual reproduction
true
What does sexual reproduction include
the fusion of male and female gametes
What happens in asexual reproduction
there is only one parent,it does not involve gametes,offspring is genetically identical,involves mitosis
Give one advantage of asexual reproduction over sexual reproduction
Population increases rapidly
What is fertilisation?
When the nuclei of egg and sperm fuse
What is a mutation?
a change in gene or chromosome
How many daughter cells does meiosis create?
4
How many chromosomes are present in human gametes?
23
which four bases are DNA made up of
A,C,T and G
On which organelle does protein synthesis occur?
Ribosome
What are examples of different types of mutations
Insertion, deletion and substitution
T or F there are around 9 million different species on earth
true
T or F scientists believe that life started on earth 3 billion years ago
true
What is the definition of evolution by natural selection
All species of living things have evolved from simple life forms
What is an allele
One of two or more versions of a genetic sequence at a particular region on a chromosome.
What is natural selection
the process through which populations of living organisms adapt and change
What is a definiton of evolution
the change in the inherited characteristics of a population over time through a process of natural selection
What is a phenotype
observable characteristics of a person
What is a genome
the entire genetic material of that organism.
Explain why there is so much genetic variation
because of mutations
When mutattions change a phenotype what normally happens
it is normally bad but very occasionally it can be beneficial like being resistant to lung disease or being able to run faster
What does DNA stand for
Deoxyribnucleic acid
Our DNA is a polymer,what does this mean
it is made up of lots of different units stuck together
When chromosomes are drawed why are they in an X shape
because that is what they look like before cell division
What is a gene
a small section of DNA that codes for a protein
What is meant by the term “inherited disease”
when our genes cause a disease
What do scientists now know about genomes ad why is it useful
they know the entire human genome,this allows them to identify the genes linked to diseases
How can we trace the migration of our ancestors with genomes
because the small differences in our genomes allow scientists to see where they have been separated from(like when humans left africa)
Describe the structure of DNA
it consists of 2 strands(each strand is known as a polymer),the 2 strands wrap around each other to form a double helix
How are proteins made
by joining together amino acids
What are the benefits of understanding the human genome
helps us search for genes that are linked to disease
