Anyone need help? (6 Viewers)

[TheOptimist]

I'll be willing to help you guy's with Bio stuff, just fire away

 

[Miss World]

what is reproduction system?

 

[TheOptimist]

what is reproduction system?

I'm not sure what you mean, if your talking about reproducitve technology then there are three main areas;
-Artificial Pollination: manually moving pollen from the anther of one plant to the stigma of another
-Artificial Insemination: introducing sperm into the vagina of a female by means other than sexual intercourse
-Cloning; garfting in plants/ twins/ somatic cell nuclear transfer e.g. dolly

 

[wavess]

Can you just briefly explain renal dialysis please

 

[BlakeOlivo]

http://community.boredofstudies.org/showthread.php?t=293130

Please help!

 

[Boonyak]

Hey thanks for the help i have two questions:

i) What the heck is xylem and phloem and how do they work
ii) What do we need to know about kidneys

Thanks.

And do we have to know all experiments

 

[BlakeOlivo]

Hi, sorry, I just want to clarify the differences/similarities in the different types of pathogens, could you quickly cover that ? thanks

 

[reflectia]

Hi! Could you explain the steps of protein synthesis as we need to know it for hsc please
I've looked through alot of textbooks/notes and they're all in different details. Thanks!

 

[Aysce]

Hey thanks for the help i have two questions:

i) What the heck is xylem and phloem and how do they work
ii) What do we need to know about kidneys

Thanks.

And do we have to know all experiments

i) The xylem and phloem are part of the transport system within the plant. Xylem transports water and ions up from the roots and only goes in 1 direction - up from the roots to usually the leaves. Phloem transport organic materials and products of photosynthesis up and down the plant.

ii) Kidneys - Know about the 3 sections and what they're responsible for: -Cortex (filtration), -Medulla (Reabsorption), -Pelvis (Collection)
- The nephron parts e.g. Loop of Henle, distal tubules, glomerulus, Bowman's capsule.
- What happens within them e.g. Tubular reabsorption, ultra filtration.
- The structure through dissection

And yes, it is safe that you know ALL experiments.

 

[BlakeOlivo]

Hi! Could you explain the steps of protein synthesis as we need to know it for hsc please
I've looked through alot of textbooks/notes and they're all in different details. Thanks!

I can help you!

The main processes you need to know is translation and transcription.

1. Transcription- Firstly, when the DNA replicates, or is divided, two template strands are exposed. Each strands nitrogenous bases are left exposed and the enzyme RNA polymerase builds a messenger mRNA strand. This mRNA strand consists of the opposite bases to that of the template strand, e.g. if the template strand has guanine (G), then the mRNA will have cytosine (c). However, the only difference is that mRNA replaces thymine with uracil, so if the template strand has adenine (A) then the mRNA will have uracil (U). This copying process is called transcription and occurs in the nucleus.

Once finished, the mRNA leaves the nucleus and translation begins.

Translation: The ribosome will attach to the mRNA strand in order to initiate the process. Firstly, a group of three bases is called a codon, and the translation process begins with the codon AUG- ALWAYS. The first step that occurs is that floating molecules called tRNA enter the ribosome, and these molecules have anti-codons, which are three bases that are opposite to the codons bases. Therefore, if the first codon is AUG, then the anti-codon on the t-RNA will be UAC. Once the anti-codon and codon are attached, the polypeptide starts in its construction, where each t-RNA molecule retains an amino acid that attaches to the next t-RNA molecule that enters the ribosome with a polypeptide link. This process continues until the whole m-RNA strand has been coded, producing a polypeptide chain, also known as a protein that serves a biological function within the body.

I know its a lengthy process, hope it makes sense, it might help to have some diagrams to look at

 

[louielouiee]

Hi! Could you explain the steps of protein synthesis as we need to know it for hsc please
I've looked through alot of textbooks/notes and they're all in different details. Thanks!

Gotta love the good ol' polypeptide synthesis. It consists of two stages: Transciption (in the nucleus) and Translation (in the cytoplasm on ribosomes)

Transcription:
1. DNA (gene) unwinds with the help of the helicase enzyme
2. RNA polymerase unzips the DNA and synthesises a mRNA strand, with the help of start (AUG) and stop (UAA) codons to control it's length, and also uracil replaces thymine
3. mRNA leaves the nucleas and...

Translation:
4. mRNA attaches to a ribosome in the cytoplasm
5. At the A and P sites of the ribosome, tRNA's carrying a specific amino acid & complementary anticodon attach to the codon on the mRNA
6. A peptide bond forms between the amino acids
7. Steps 5 & 6 are repeated as the ribosome moves along the mRNA & a polypeptide chain is synthesised.
8. Steps 1-7 are repeated.


Now, I do the Genetics option, so I may have gone into more detail than required. Hope this helps!

 

[Cupcake16XD]

Hi! Could you explain the steps of protein synthesis as we need to know it for hsc please
I've looked through alot of textbooks/notes and they're all in different details. Thanks!

http://www.wisc-online.com/objects/ViewObject.aspx?ID=ap1302

This animation's really helpful and easy to understand ^^

 

[Aysce]

Top effort from the two of you.

I'll be back to answer any questions after I wrap up a few loose ends.

 

[Alkanes]

Hey could anyone please explain to me sex linked inheritance.

And also how would i interpret sex linkage inheritance from a pedigree?

 

[madharris]

Hi, sorry, I just want to clarify the differences/similarities in the different types of pathogens, could you quickly cover that ? thanks

Viruses:
Non cellular - made of a protective coat of DNA or RNA
Found in eukaryotic and prokaryotic cells
THey enter the host cells and reproduce, causing it to burst, and is free to do this with other cells
No cure however vaccines can reduce occurrence
E.g. Small pox, influenza virus

Protozoans:
Unicellular
Eukayotic
no cell wall
Reproduce through binary fission
Some are pathogenic, some are neutral
E.g. Malaria

Bacteria:
Unicellular, prokaryotic
Invades cells, secretes toxins, disrupts normal cell functioning/division
Some are pathogenic, some are neutral and some are useful
E.g. Diptheria and Tuberculosis

Macro parasites:
Large - can be seen with naked eye
Endoparasites - inside the body and causes diseases e.g. tapeworm cyst
Ectoparasite - live outside body, sucks blood e.g. tick

Fungi
Eukaryotic
Some are eukaryotic, most are multicellular
Produces fruiting bodies which contain thousand of spores
E.g. Thrush (animal), cinnamon root (plant)

 

[louielouiee]

Hey could anyone please explain to me sex linked inheritance.

And also how would i interpret sex linkage inheritance from a pedigree?

Sex-linkage:
- Genetic information is carried on the X chromosome, not the Y.
-Hence, females are usually carriers if they are heterozygous. If they are homozygous dominant, they are not diseased and are not carriers. If they are homozygous recessive (which is EXTREMELY rare) then they express the disease.
-Males are either affected or unaffected- that is, they either have a dominant (normal) or recessive (disease) from their mother. They can't be carriers due to the presence of the Y chromosome.
-During fertilisation is where sex-linkage occurs.


From a pedigree:
- Only males will be affected. This is because sex-linked genes only occur on the X chromsome and the Y chromosome doesn't carry any genetic information. MAYBE one female would be affected, but this would be very unlikely as the female would have to have the recessive XX allele.

 

[madharris]

Hey could anyone please explain to me sex linked inheritance.

And also how would i interpret sex linkage inheritance from a pedigree?

If two non-affected parents have an affected child - recessive
If two affected parents have a non-affected child - dominant
Large bias towards males being affected, sometimes generations are skipped - most likely sex linked (females can still inherit sex linked diseases though)
However, you can always work it out with punnet squares if you're completely confused

Sex-linked traits are only carried on the X chromosome.
This means that since males only have 1 X chromosome, they can't be recessive for it and will inherit disease
However, since females have 2 X chromosomes, there is less chance that they will inherit the disease, as they will more likely be recessive for the disease
(Is that what you wanted to know?)

 

[BlakeOlivo]

Viruses:
Non cellular - made of a protective coat of DNA or RNA
Found in eukaryotic and prokaryotic cells
THey enter the host cells and reproduce, causing it to burst, and is free to do this with other cells
No cure however vaccines can reduce occurrence
E.g. Small pox, influenza virus

Protozoans:
Unicellular
Eukayotic
no cell wall
Reproduce through binary fission
Some are pathogenic, some are neutral
E.g. Malaria

Bacteria:
Unicellular, prokaryotic
Invades cells, secretes toxins, disrupts normal cell functioning/division
Some are pathogenic, some are neutral and some are useful
E.g. Diptheria and Tuberculosis

Macro parasites:
Large - can be seen with naked eye
Endoparasites - inside the body and causes diseases e.g. tapeworm cyst
Ectoparasite - live outside body, sucks blood e.g. tick

Fungi
Eukaryotic
Some are eukaryotic, most are multicellular
Produces fruiting bodies which contain thousand of spores
E.g. Thrush (animal), cinnamon root (plant)

LEGEND! Thank you so much

 

[Aysce]

LEGEND! Thank you so much

Just to add to madharris' wonderful post, you should also know their relative size!

Let me post from smallest to largest pathogen:

Prions, Viruses, Bacteria, Protozoans, Fungi and Macro-parasites

 

[Aysce]

LEGEND! Thank you so much

Just to add to madharris' wonderful post, you should also know their relative size!

Let me post from smallest to largest pathogen:

Prions, Viruses, Bacteria, Protozoans, Fungi and Macro-parasites