Turn on thread page Beta
    • Thread Starter
    Offline

    7
    ReputationRep:
    Hi I need help with a few things, in biology when interpreting a graph what does a high standard deviation show? the data is more spread out but does this undermine the reliability of it and mean there are more anamolous results?

    Also is ATP energy source or energy storage?

    Lastly, could someone define the terms DNA Chromosomes and Genes explaining the difference between them in a really simple way? thanks
    Offline

    15
    ReputationRep:
    Hi,

    1. A larger value of standard deviation does provide some info that the data is more widely spread around the mean - however, it can also be high if there is less data i.e. n is low AND there are one or two outliers. One of the things that SD tells us is that for a normal (Gaussian) distribution, 97% of the data lies within 5 SDs either side of the mean - this gives us an idea as to the most likely location of a particular value, although standard error might be a better predictor. The brief answer to your Q is Yes!

    2. ATP is the form in which energy is stored as well as provided in nature, so both! When ADP is phosphorylated to give ATP, energy is taken up and stored in that extra phosphate bond, in a way in the form of potential chemical energy. When ATP breaks down to ADP and phosphate, the energy released is used in the sense that it is converted to another form of energy (remember: energy can neither be created nor destroyed - only changed) in a useful way e.g. it is converted to kinetic energy to produce contraction of muscle resulting in movement of say your arm OR it can be used by a plant in photosynthesis to store it as chemical energy (again!) in the form of C6H12O6 (glucose).

    3. Chromosomes are the actual structures you can see as X-shaped double strands of two chromatids under the microscope; DNA is deoxyribonucleic acid, the chemical that makes up the chromosomes (it consists of a double helix (=spiral) of two strands of polynucleotides twisted around each other with hydrogen bonds between each adenine to thymine AND cytosine to guanine, [A-T AND C-G], respectively. Poly- means very many - nucleotide is a complex of 3 things: a nitrogen base, a pentose sugar (deoxyribose) and a phosphate group. A gene is a part of a chromosome (or a section of DNA out of the total chain of DNA that makes up a whole chromosome) that CODES FOR ONE SPECIFIC PROTEIN.

    Go through my attached Powerpoint file - if confused.com after that, PM me.

    Good luck!

    M (specialist biology tutor)
    Attached Files
  1. File Type: ppt DNA + Prot Synth.ppt (910.5 KB, 56 views)
    Offline

    15
    ReputationRep:
    I'm going for question 3....

    DNA (Deoxyribo Nucleic Acid) is a self-replicating macromolecule which carries the cell's genetic information
    Inherited characteristics are passed down from parent to offspring mainly in the form of a chemical code. This code is a long - very long - molecule called DNA, found in the cell nucleus.(it is self replicating because the cell has the ability to reproduce precisely the base pair sequence of a DNA molecule using its own machinery of enzymes etc).

    Its the structure of DNA that makes it possible to carry a code. It is a double helix, like a spiral staircase, with a sugar-phosphate backbone (the hand rails) and stairs which are formed by paired bases - one attached to the left hand rail, the other attached to the right. There are 4 kinds of bases, and they always pair up A-T and G-C. A length of DNA therefore can be represented as a long sequence like this: AGCTCTATTGCAACTGTGGAATTTCTTAC... ..etc

    The code can be "read" by specialist enzymes, because it turns out that every 3 letters represents a specific amino acid. For example, AGC might code for alanine, TCT for tyrosine and so on (I've made these up, but you get the idea). A string of amino acids, when joined together, makes a protein.

    Proteins are the basis for many of the key chemicals needed by the cell - for example, enzymes are proteins, so a particular stretch of DNA codes for a long string of amino acids. These sequences are translated and turned into proteins, and because most cells contain many millions of DNA base-pairs, this means that they can be turned into a vast number of proteins (or more generally, many different "gene products").

    A gene is a section of DNA which functions as a unit to determine a particular trait and which tends to be inherited as a unit (genes are often defined as "the unit of inheritance")

    Each stretch of DNA that codes for an identifiable, specific, product is called a gene. Gene products are proteins (and other molecules) and they are what gives an animal a particular feature or ability (its phenotype). They are usually inherited as a distinct, intact unit, so that parents can pass a specific form of a gene down to their offspring. Some individuals have slight variations in the precise base pair sequences, so you this gives a population some variability, both in it DNA/gene sequence, and in its abilities and features). Like many animals, humans have two copies of every gene (one from our mother and one from our father).

    Chromosomes are structures made up of DNA plus structural proteins.

    Most of the time, our DNA is unravelled because it is being actively transcribed - our cells are constantly busy producing stuff. But shortly before a cell divides, the DNA gets contracted into compact structures called chromosomes. These are simply lengths of DNA, wrapped up in protective and regulatory proteins so that cell division can proceed easily. Every species has a constant number of chromosomes (humans have 46).
    • Thread Starter
    Offline

    7
    ReputationRep:
    (Original post by OxFossil)
    I'm going for question 3....

    DNA (Deoxyribo Nucleic Acid) is a self-replicating macromolecule which carries the cell's genetic information
    Inherited characteristics are passed down from parent to offspring mainly in the form of a chemical code. This code is a long - very long - molecule called DNA, found in the cell nucleus.(it is self replicating because the cell has the ability to reproduce precisely the base pair sequence of a DNA molecule using its own machinery of enzymes etc).

    Its the structure of DNA that makes it possible to carry a code. It is a double helix, like a spiral staircase, with a sugar-phosphate backbone (the hand rails) and stairs which are formed by paired bases - one attached to the left hand rail, the other attached to the right. There are 4 kinds of bases, and they always pair up A-T and G-C. A length of DNA therefore can be represented as a long sequence like this: AGCTCTATTGCAACTGTGGAATTTCTTAC... ..etc

    The code can be "read" by specialist enzymes, because it turns out that every 3 letters represents a specific amino acid. For example, AGC might code for alanine, TCT for tyrosine and so on (I've made these up, but you get the idea). A string of amino acids, when joined together, makes a protein.

    Proteins are the basis for many of the key chemicals needed by the cell - for example, enzymes are proteins, so a particular stretch of DNA codes for a long string of amino acids. These sequences are translated and turned into proteins, and because most cells contain many millions of DNA base-pairs, this means that they can be turned into a vast number of proteins (or more generally, many different "gene products".

    A gene is a section of DNA which functions as a unit to determine a particular trait and which tends to be inherited as a unit (genes are often defined as "the unit of inheritance"

    Each stretch of DNA that codes for an identifiable, specific, product is called a gene. Gene products are proteins (and other molecules) and they are what gives an animal a particular feature or ability (its phenotype). They are usually inherited as a distinct, intact unit, so that parents can pass a specific form of a gene down to their offspring. Some individuals have slight variations in the precise base pair sequences, so you this gives a population some variability, both in it DNA/gene sequence, and in its abilities and features). Like many animals, humans have two copies of every gene (one from our mother and one from our father).

    Chromosomes are structures made up of DNA plus structural proteins.

    Most of the time, our DNA is unravelled because it is being actively transcribed - our cells are constantly busy producing stuff. But shortly before a cell divides, the DNA gets contracted into compact structures called chromosomes. These are simply lengths of DNA, wrapped up in protective and regulatory proteins so that cell division can proceed easily. Every species has a constant number of chromosomes (humans have 46).
    Thank u soo much
    • Thread Starter
    Offline

    7
    ReputationRep:
    (Original post by macpatelgh)
    Hi,

    1. A larger value of standard deviation does provide some info that the data is more widely spread around the mean - however, it can also be high if there is less data i.e. n is low AND there are one or two outliers. One of the things that SD tells us is that for a normal (Gaussian) distribution, 97% of the data lies within 5 SDs either side of the mean - this gives us an idea as to the most likely location of a particular value, although standard error might be a better predictor. The brief answer to your Q is Yes!

    2. ATP is the form in which energy is stored as well as provided in nature, so both! When ADP is phosphorylated to give ATP, energy is taken up and stored in that extra phosphate bond, in a way in the form of potential chemical energy. When ATP breaks down to ADP and phosphate, the energy released is used in the sense that it is converted to another form of energy (remember: energy can neither be created nor destroyed - only changed) in a useful way e.g. it is converted to kinetic energy to produce contraction of muscle resulting in movement of say your arm OR it can be used by a plant in photosynthesis to store it as chemical energy (again!) in the form of C6H12O6 (glucose).

    3. Chromosomes are the actual structures you can see as X-shaped double strands of two chromatids under the microscope; DNA is deoxyribonucleic acid, the chemical that makes up the chromosomes (it consists of a double helix (=spiral) of two strands of polynucleotides twisted around each other with hydrogen bonds between each adenine to thymine AND cytosine to guanine, [A-T AND C-G], respectively. Poly- means very many - nucleotide is a complex of 3 things: a nitrogen base, a pentose sugar (deoxyribose) and a phosphate group. A gene is a part of a chromosome (or a section of DNA out of the total chain of DNA that makes up a whole chromosome) that CODES FOR ONE SPECIFIC PROTEIN.

    Go through my attached Powerpoint file - if confused.com after that, PM me.

    Good luck!

    M (specialist biology tutor)
    Thank you so much, that was so useful
    I had another question, you know for insects, my textbook says that they have a large surface area to volume ratio but it also sAys that they have adapted to have a small surface area to volume ratio to reduce water loss, which is true?
    Offline

    15
    ReputationRep:
    (Original post by Pebbles47)
    Thank you so much, that was so useful
    I had another question, you know for insects, my textbook says that they have a large surface area to volume ratio but it also sAys that they have adapted to have a small surface area to volume ratio to reduce water loss, which is true?
    Good morning,

    BTW, do you live in Brighton (just wondered if your username came to mind when sitting on the (uncomfortable!) beach there)?

    OK let us take your Q by the neck. First thing to say is "how long is a string?".

    What I mean is that the surface area to volume ratio being a problem in being too low in magnitude is a problem for all organisms that consist of more than a few cells. So, if you consider a unicellular organism such as a bacterium OR a protozoan e.g. plasmodium (malaria parasite) OR amoeba, then, in comparison to its volume of protoplasm (living material like), its surface area is massive. A similar situation prevails for an organism with just a few cells e.g. Paramecium [which is like a chain of single cells in line); next, getting bigger, even Hydra does not have a major problem (slightly less surface area to volume ratio).

    It is when you start getting to organisms even bigger (going from small to large) through the animal kingdom for example: Arthropoda (Greek arthro = joint; podo = leg: so having jointed legs [you will remember noticing that insects and spiders have little lumps in the middle of their legs haha) [arthropods include Insecta (obvious), Arachnida (spiders), Crustacea (e.g. crabs, lobsters) AND Mollusca (e.g. snails)]) then bigger going to vertebrates (those having a backbone) from Pisces ([check pic of star sign] fish = still in water [you know life started in water]) then Amphibia (ampho = both; frogs can live in BOTH land and water), then Reptilia (e.g. crocs, look out before jumping into rivers in Kenya , where I was born!), [getting onto land] then Aves (aviation = flight)(birds starting to take off haha), then us Mammalia.

    ALL THESE FROM the last paragraph started having problems with too little surface area [e.g. dogs have to stick out their dirty tongues to release heat after running, elephants have large flat ears for the same reason, AND ALL THESE "higher organisms" DEVELOPED [through evolution] SPECIALIZED ORGANS to allow food and oxygen etc. to reach all their cells [lungs and heart in mammals or birds, gills in fish]. and to get rid of toxic waste {e.g. liver and kidneys)] BECAUSE DIFFUSION ALONE WAS NO LONGER ENOUGH TO PERFORM THIS EXCHANGE OF MATERIALS AND OF HEAT since cells are TOO FAR from the outside environment].

    Sorry about this PhD thesis above , but we now come to your Q. So INSECTS HAVE A RELATIVELY SMALL SURFACE AREA TO VOLUME RATIO (remember: "how long is a string?" above?) they consist of many thousands of cells not just one or even a few. So the first quote from your book is b*****i*.

    The second part is also not entirely true - the fact that they have a small surface area to volume ration is not by design, it is an inevitable result of the size of the insect (Very large compared to an amoeba); Yes, it does help in reducing water loss, but the feature that (intentionally, if you think teleologically [google this word]) helps reduce water loss is its water-proof layer on its outside called a cuticle (the reason why cockroaches look shiny!!

    I hope this makes things clearer! BTW, which board are you doing, and which book do you use, if I may ask?

    M
    Offline

    15
    ReputationRep:
    Ok of course you are doing AQA - lost track of the title of your thread - which book??
    Offline

    20
    ReputationRep:
    (Original post by Pebbles47)
    Hi I need help with a few things, in biology when interpreting a graph what does a high standard deviation show? the data is more spread out but does this undermine the reliability of it and mean there are more anamolous results?

    Also is ATP energy source or energy storage?

    Lastly, could someone define the terms DNA Chromosomes and Genes explaining the difference between them in a really simple way? thanks
    I think you need to be a little bit careful with the ATP question. It's a currency - the way energy is trapped from fuel sources via respiration and made available to cells to do work. It's not a 'store' as such, in that there is a huge turnover of ATP - we get through about 70kg of it a day, but there is a tiny fraction of this amount at any one time. An energy store would be something like adipose tissue, where the triacylglycerols can be mobilised when required to synthesis ATP. However, there is at any given time an amount of ATP present in a cell, and so it could be thought of as a short-term energy store from this point.

    Neither is ATP a 'source' of energy - the actual source of the energy is from dietary macronutrients, not ATP. Again, it is a 'source' of energy in that the breaking of the high energy phosphoryl bonds in ATP is where the energy 'comes from', but it is not the real source (an added problem here is how far back do you want to go? In the end, the ultimate energy source is the Sun, but that's probably pushing it a bit).

    Just depends on how accurate you want/need to be.
    Offline

    15
    ReputationRep:
    (Original post by Pebbles47)
    ...for insects, my textbook says that they have a large surface area to volume ratio but it also sAys that they have adapted to have a small surface area to volume ratio to reduce water loss, which is true?
    My take on the way your book may be thinking is this:

    Insects are small creatures compared to - say - reptiles, birds and mammals. This enables them to exploit many niches that larger animals cannot. But it means that they have a comparatively large SA:V ratio, which makes them susceptible to rapid water loss.

    Where this is a survival problem, many have evolved shapes and structures to minimise water loss. One way of doing this without going big and losing the advantages of small body size is to have a bodyshape that is rounded and compact - reducing their SA:V ratio to a minimum for that size.
    Offline

    14
    ReputationRep:
    hey! has anyone got their hands on the 2017 biology papers by any chance?
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: June 7, 2017
The home of Results and Clearing

2,987

people online now

1,567,000

students helped last year

University open days

  1. Sheffield Hallam University
    City Campus Undergraduate
    Tue, 21 Aug '18
  2. Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 22 Aug '18
  3. University of Buckingham
    Postgraduate Open Evening Postgraduate
    Thu, 23 Aug '18
Poll
How are you feeling about GCSE results day?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.