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Biology, Exam questions, New biology - Coggle Diagram

- - - - Growth occurs thoruh cell division and diffenrentiation.
      - Cell division occurs through mitosis after which cells an be differentiated into specialised forms.
      - Animal cells can differentiate at early stages but later lose the ability
      - In mature animal cells , cell division moistly happens to repair damaged cells as they undergrow little growth.
    - - Plants grow by cell differentiation and cell division.
      - Diferention occurs in the Meristem
      - In plants , differentiation can occurs in the roots and shoots
      - Plants can differentiate all throughout their lifetime.
  - - - Metaphase
        
        the chromosomes line up to the equator as spindle fires pull the chromosomes towers the equator of the cell.
      - Anaphase
        
        spindel fibres pull the chromaomes away from the centre onto the poles of the cell.
      - Prophase
        
        Additionally , the cell begins to form the "x" charicterisistc as the precipitate begins to condense.
      - Telekinesis
        
        The nuclear membrane begins to collapse and form into two as well as the nucleus.
      - Interphase
        
        All the organelles within the cells replicate meaning that the DNA has been replicated. Additionally , the cell begins to form the "x" charicterisistc
      - Cytokinesis
        
        Two new daughter cells are created. They are haploid which means they contain half of the genetic information.
  - - - A stem cell is an undifferentiated cell which can undergo cell division to produce more similar cells. these cells can then turn into any cell and preform their function.
    - - Adult stem cells
        
        Adult stem cells can be found in the one marrow.
        
        They can only differentiate into certain types of cells and tissues.
      - Embryonic stem cells.
        
        Embryonic stem cells are formed when an egg and a sperm fuse to form a zygote.
        
        they can differentiate into any tupe of cell within the body.
        
        Scientists can clone the cell and make them into any type of cell.
        
        These could be used in medicinal applications such as replace insulin , regenerate the effects of Alzheimer's or replace damaged or dead nerve cells in the paralysed.
      - Meristem
        
        The meristem is found in the roots and shoots of a plant.
        
        Like the embreyonic stem el , they can differentiate into any typeof plant throughout the cell.
        
        They can be used to make clones of plants.
    - - Therapeutic cloning evolves the embryo being produced with the same genes as the patient.
      - The embreyo first produced can be then harvested to obtain hte embreyonic stem cells.
      - These could be grown into different cells the patient needs such as tissues or organs.
      - The advantage is that they could not be rejected as they are the patients own cells.
    - - Advantages
        
        Unwanted embryos form fertility clinics can be used / given a function as they would have been dissuaded.
        
        It allows research into stem cell research
        
        Can be used to replaced damaged or diseased tissues.
      - Disadvantages
        
        Lack of knowledge into the process of differentiation
        
        Removal of stem cells can result in destruction of the embryo
        
        People might have Religious or ethical objections as it can interfere with the natural process of reproduction.
        
        If the growing stem cell is contaminated , the contamination will be spread.
        
        It takes money and time that could be allocated elsewhere.
- - - - Poputlations of a species become isolated through hysical bariors preventing them from breeding together.
      - Different alles may have some advantages in some environments leading to them being selected.
      - The allels which provide survival advantages are selected through natural selection
      - Over time , selection of diferent alleles increeses Ginetic variation between populations.
      - Variation exists within a poulation resulting in ginetic mutation
      - Whem they are no longer able to breed to produce fertile offspring , they are seen as a new species.
    - - Variation exists within species and results in DNA mutations
      - Organisms with the charicterisitcs most suited o the envroment are more likely to survie
      - The beneficial characteristics are the passed on to the next generation.
      - Over time , the gernerations posess the allies that allow them to survive and so the ale is passed on. This is called the survival of the fittest.
    - - It went against the notiuon that G-d was the creator of all species.
      - Lack of enough evidence.
      - The mechanism of variation and inheritance was not known.
  - - - as a result . those with antibiotic resisitncve casn pass on the advantageus gene. Therefore , the presence of a new bacteria has been selected by the embrionment.
      - The population of antibiotic bacteria increeses
      - Exposure to antibacterial cerates a selection pressure as those without the antibiotic gene don't survive.
      - The bacteria diseases spreads rapidly
      - Mutations During the reproductionstage casn result in the formation of new genes such as anti biotic reisitance.
      - Bacteria reproduce quickly though Binary fission.
  - - - ARDI - the oldest hominid
      - Lucy - walked in an upright human-like position
  - - - Selective breeding is when humans breed organisms to produce offspring's with desirable characteristics. This happens over a matter of years.
        
        They are bread together
        
        The offspring's which have the desired characteristics are bread together.
        
        A parent with the desired characteristics is identified.
        
        The process is repeated countless times until they have the desired characteristics.
      - Problems
        
        Inbreeding due to the small gene pool
        
        If released into the environment , it can cause disease / problems.
        
        Severe economic problems as a country relies on one type of crop.
    - - Genetic engineering is the modification of the genome of offspring by introducing a gene which poses the desired characteristic.
        
        stages of Genetic engeneering.
        
        Restriction enzymes are used to cut out a desired gene from a cell.
        
        The same restriction enzye is used to ut a vectointo which the genes will be placed.
        
        Ligase enzyme is used to attach to the sticky ends of the gene and vector together, to produce a recombinant gene product.
        
        The vector is then placed into a cell.
        
        The cell splits though binary fission and the gene is reproduced.
        
        Disadvatages
        
        Might have an impact on the emvironemtn
        
        People are woried about he affects n hunman health
        
        Could lead to increased resistance in bacteria.
        
        Advantages
        
        It can be very useful in medicin to mass produce certain hormones
        
        It can improve crop yields
        
        Crops can ave extra vitamins where it is difficult to obtain.
- - - - Stage 2
        
        The cells divide into identical daughter cells.
      - Stage 3
        
        4 non identical cells are created which are diploid and contain 23 cells being haploid.
      - Stage 1
        
        Te cells make copies of each other so that the amount of ginetic information is doubled.
  - - - The DNA is found within the nucleus and contains the genetic information
      - DNA is a ploymere
      - Structure
        
        DNA is a polymer.
        
        It is made of nucleotides.
        
        Each nucleotides is made from one sugar molecule and one Phosphate molecule.
        
        Each nucleotide is made up of four bases : A ,T, G, C
        
        Each DNA molecule is held together by two strands twisted together. this called a double helix.
        
        Definition
        
        DNA is a polymer made up of two strands which are wound around each other forming a double helix.
        
        A gene s a section of DNA. Each Gene is responsible for coding for amino acids which , when joined together , form amino acids.
        
        The word genome refers to ll of the genetic information of an orgasm
    - - Filter out the solution using a few sheets of Kitechen paper and sieve.
      - Add ice cold ethanol to the mixture,
      - Remove the skin and pulverise the fruit.
      - prepare a solution of water and washing up liquid and heat the mixture.
      - Observations
        
        A white mass should participate at the top of the tube after 10 minutes.
      - Reasons
        
        Why is Ethanol added?
        
        So that the DNA could precipitate.
        
        Why is the salt needed?
        
        It is needed to neutralise the DNA'S charges
- - - - The cells in the chromosomes , which make up DNA are replicated and copied so that there are two sets of chromosomes.
      - This is the initial stage of the growth phase. Extra ribosomes , mitochondria and other subcellular structures are produced.
    - - In the stage of mitosis , the two sets of chromosomes are pulled to opposite ends of the cells.
      - The nucleus divides into two
    - - The cells cytoplasm and the membrane divides into two identical diploid cells with two sets of chromosomes.
  - - - the two sets are pulled to the equator of the cell by spindle fibre .
    - - The chromosomes are pulled to the poles of the sells by spinal fibres.
    - - The nucleus splits into two new nuclei.