duquesne's Bio 3/4 Question Thread

[duquesne9995]

Hi everyone,
I'm taking up 3/4 without having done 1/2, so some of my questions will be a bit noob, please bear with me.
Thank you heaps in advance! 

To start off:

- In DNA, can the letters ATCG be used to denote the bases or the nucleotides (with the sugar and phosphate included)? Because I've heard that the nucleotides are in fact dGTP for deoxyguanosine triphosphate, dATP for deoxyadenosine triphosphate, dTTP for thymidine triphosphate and dCTP for deoxycytidine triphosphate, and that ATCG should only be used for referring to the bases.

- In active transport, are carrier proteins/molecules always required? And are carrier proteins specific to a certain substance and a certain mode of transport (i.e. facilitated diffusion and active transport)?

- Can organelles move around in the cytosol by themselves?

- Do vesicles secreted from the Golgi Body travel through ER to get to the cell membrane or can they just travel through the cytoplasm to be secreted?

- Do lysosomes have a double membrane?

- Are the membranes of organelles similar to a cell membrane?

- How do the chromosomes and chromatids get pulled apart in anaphase in plant cells if they don't have centrioles?

- Is there any difference between the words replication and duplication?

Thank you!

[Bhootnike]

- In DNA, can the letters ATCG be used to denote the bases or the nucleotides (with the sugar and phosphate included)? Because I've heard that the nucleotides are in fact dGTP for deoxyguanosine triphosphate, dATP for deoxyadenosine triphosphate, dTTP for thymidine triphosphate and dCTP for deoxycytidine triphosphate, and that ATCG should only be used for referring to the bases.

ATCG are the nitrogenous bases, which are a part of a nucleotide, and nucleotides are the building blocks of nucleic acids. each nucleotide consists of the sugar, either ribose or deoxyribose. if ribose, the bases are AUCG, since T (thymine) is only present in DNA. not RNA. if deoxyribose, then simply ATCG.

Do vesicles secreted from the Golgi Body travel through ER to get to the cell membrane or can they just travel through the cytoplasm to be secreted?

'
lol been a while, but i have a feeling that they just go straight out. someone might wanna check up on this tho!

Are the membranes of organelles similar to a cell membrane?

once again, been a while, but im pretty sure its the same deal..

In active transport, are carrier proteins/molecules always required? And are carrier proteins specific to a certain substance and a certain mode of transport (i.e. facilitated diffusion and active transport)?

once again, .. been a while :p but im pretty sure yeah theyre required. and yes i guess carrier proteins would have to be specific since proteins have a specific substrate upon which they on.

[CaiTheHuman]

Plasma Membranes are generally thicker then membranes of organelles.

Chromosomes get pulled apart in anaphase in plant cells by microtubules

[ggxoxo]

1- Can organelles move around in the cytosol by themselves?

They move in a circular motion that biologists call 'cytoplasmic streaming'- this is caused because of the fluid nature of the cell and because of actin filaments so I wouldn't say they move 'by themselves'

2- Do vesicles secreted from the Golgi Body travel through ER to get to the cell membrane or can they just travel through the cytoplasm to be secreted?

The general step is: ER (don't just use ER in the exam btw! You have to say its full name!)--> Golgi --> plasma membrane; so yea they just travel through the cytoplasm to the plasma membrane after Golgi.

3- - Do lysosomes have a double membrane?
No- they are single-membraned organelles.

4-Is there any difference between the words replication and duplication?
Replication is the process of copying a genetic material to make 2 copies.

Duplication is a type of mutation.

[duquesne9995]

Thanks for the answers

Just to clarify my first question, I'm asking can I use the letters ATGC to denote the nucleotide which contains that base? For example, T stands for Thymine, so does that mean I can only use T when I'm referring to the base? What if I want to refer to the nucleotide, can I still use the letter T?

Some more questions:
9. Can cell walls (in bacteria), flagella, cilia and pili be seen with a light microscope?

10. What is the difference between cilia and pili and microvilli? How can I tell them apart in a diagram, labelling the organelles type activity? I've only seen pili mentioned in one book and I haven't seen it in NOB, do I need to know about it?

11. Is catabolism = hydrolysis and anabolism = synthesis, so can I use them interchangeably?

12. Is it sufficient to say that the cell walls of bacteria are composed of complex polysaccharides?

13. What is the difference between chromosomes and chromatin? I know that they are both composed of DNA, is it that the DNA is referred to as chromosomes in mitosis and chromatin at all other times?

14. If I am given a diagram of a cell to label, and one of the lines/arrows is pointing to the liquid part of the cell, do I label it as the cytoplasm or the cytosol? I've mostly seen it labelled as the cytoplasm, so would it be incorrect to label it as cytosol? Why/why not?

15. Monera and Archaea are considered living things, but they don't have mitochondria so how do they get their energy?

Thank you

[ggxoxo]

(1) Just to clarify my first question, I'm asking can I use the letters ATGC to denote the nucleotide which contains that base? For example, T stands for Thymine, so does that mean I can only use T when I'm referring to the base? What if I want to refer to the nucleotide, can I still use the letter T?

I am really confused with the wording of your question; what are you really asking?

10. What is the difference between cilia and pili and microvilli? How can I tell them apart in a diagram, labelling the organelles type activity? I've only seen pili mentioned in one book and I haven't seen it in NOB, do I need to know about it?

Cilia are the tiny hair-like projections in our respiratory tract (for filtering) or on some single-celled organisms that can help them move.

Pilli are what bacteria use to trade plasmids and hence pass on resistance to otehr bacteria.

Microvilli are projections on our small intestines to increase SA:V

I wouldn't spend too much time on these.

11. Is catabolism = hydrolysis and anabolism = synthesis, so can I use them interchangeably?
A great mnemonic to remember: 'CATS EXPIRE'

Catabolism=exergonic (release energy)=respire (splitting of molecules) [think of cats ripping things; catabolism is all about splitting molecules]

hence,

Anabolism=endergonic (absorb energy)= photosynthesis (build-up of molecule)

They are two completetly different things; and VCAA wants you to know the relationship I have just illustrated above.

12. Is it sufficient to say that the cell walls of bacteria are composed of complex polysaccharides?

Yes; I think the important thing you need to know is that bacterial cell wall is made of polysaccharides (not cellulose as in plant cells)

14. If I am given a diagram of a cell to label, and one of the lines/arrows is pointing to the liquid part of the cell, do I label it as the cytoplasm or the cytosol? I've mostly seen it labelled as the cytoplasm, so would it be incorrect to label it as cytosol? Why/why not?

OK this is delving into technicality. If it is pointing to the liquid part of a cell I would name it cytosol (because cytosol is technically the "liquid" part of the cytoplasm). Cytoplasm is merely a general term describing the area outside the nucleus (i.e. cytoplasm= organelles + cytosol).

In saying that, unless otherwise made clearer, if they are pointing to the liquid part of the cell, they would have to accept both cytosol and cytoplasm.

15. Monera and Archaea are considered living things, but they don't have mitochondria so how do they get their energy?

They have all the enzymes needed to undertake cellular respiration and a special region called mesosomes.

13. What is the difference between chromosomes and chromatin? I know that they are both composed of DNA, is it that the DNA is referred to as chromosomes in mitosis and chromatin at all other times?

Check attachement!


 

[duquesne9995]

(1) Just to clarify my first question, I'm asking can I use the letters ATGC to denote the nucleotide which contains that base? For example, T stands for Thymine, so does that mean I can only use T when I'm referring to the base? What if I want to refer to the nucleotide, can I still use the letter T?

I am really confused with the wording of your question; what are you really asking?

Can I use the letter T to refer to thymine + phosphate + sugar (the whole nucleotide), or just T = thymine. If T is just = thymine, then what do I use to refer to thymine + phosphate + sugar?

11. Is catabolism = hydrolysis and anabolism = synthesis, so can I use them interchangeably?
A great mnemonic to remember: 'CATS EXPIRE'

Catabolism=exergonic (release energy)=respire (splitting of molecules) [think of cats ripping things; catabolism is all about splitting molecules]

hence,

Anabolism=endergonic (absorb energy)= photosynthesis (build-up of molecule)

They are two completetly different things; and VCAA wants you to know the relationship I have just illustrated above.

Okay, then how do hydrolysis and synthesis fit in? Do I need to know about them?

13. What is the difference between chromosomes and chromatin? I know that they are both composed of DNA, is it that the DNA is referred to as chromosomes in mitosis and chromatin at all other times?

Check attachement!

So does chromatin = chromatid? I've always used the word chromatid for that part of a replicated chromosome.

Great explanations. Thanks.

[Scooby]

So does chromatin = chromatid? I've always used the word chromatid for that part of a replicated chromosome.

They're a bit different. Individually, sister chromatids are referred to as a chromatid. A chromatid is basically just one of the two copies of a duplicated chromosome. Chromatin is the combination of DNA and protein (mostly histone) found in the nucleus.

Okay, then how do hydrolysis and synthesis fit in? Do I need to know about them?

Hydrolysis is the separation of two molecules (eg. a dipeptide into two amino acids; a disaccharide into two monosaccharides) with the addition of water. It is exergonic because the energy stored within the bonds that linked the two molecules is released into the surroundings, and also catabolic because it involves the breakdown of molecules into smaller subunits.
A condensation reaction is the linkage of two molecules (two amino acids to form a dipeptide; two monosaccharides to form a disaccharide) and it releases water. It is endergonic because energy from the surroundings is taken and stored in the bonds between the molecules that are linked, and also anabolic because it involves the building of molecules from smaller subunits.

[ggxoxo]

(1) Can I use the letter T to refer to thymine + phosphate + sugar (the whole nucleotide), or just T = thymine. If T is just = thymine, then what do I use to refer to thymine + phosphate + sugar?

'Thymine + phosphate + sugar' is just referred to as a nucleotide or to be specific 'a nucleotide with a nitrogenous base of thymine' (do not just refer to it as T!)

(2) Okay, then how do hydrolysis and synthesis fit in? Do I need to know about them?
Hydrolysis and Condensation (aka synthesis) are two different things.

Hydrolysis is when you split up molecules by adding water. Essentially, cellular respiration involves hydrolysis because you are splitting glucose molecules to release energy.

Condensation reactions (aka synthesis) is when you remove water to join 2 molecules together.

Here watch this: http://academic.cengage.com/biology/discipline_content/animations/reaction_types.html

This is important when you study biomolecules because condensation reactions are used to build up polymers whereas hydrolysis is used to break apart polymers.

Also don't forget the mnemonic: CATS EXPIRE!!! It can come very handy!

[LOLs99]

Cats expire= catabolic exergonic reSpire?

[ggxoxo]

^yea they were like CATS EXSPIRE but the S is sort of silent anyway so I sort of just forgt about it lol

[LOLs99]

LOL then CAT EXPIRE. Any mnemonics for others? I found out that it's quite effective and fun compared to rote learning.

[duquesne9995]

Can you say that skeletal muscles engage in aerobic respiration or is it more correct to say that skeletal muscle cells engage in aerobic respiration. Or is that just being too pedantic?

Edit: Also, what is the difference between antibodies and white blood cells?

[Reckoner]

"Cells" I believe would technically be correct, but I doubt you would lose marks for not using the word cells. That being said, it certainly won't hurt if you do.

[Scooby]

Edit: Also, what is the difference between antibodies and white blood cells?

Antibodies are proteins released by plasma B cells that attach to antigens - proteins found on the surface of pathogens - and allow these pathogens to be identified and destroyed by other white blood cells.

White blood cell is the general term for the cells of the immune system. Essentially these can be broken up into lymphocytes and phagocytes.

Lymphocytes include T cells and B cells. Cytotoxic T cells destroy virus-infected cells and malignant cells, and helper T cells help activate B cells during the immune response. The main role of a B cell is to release antibodies. Phagocytes are cells that engulf (phagocytose) bacteria and other foreign bodies.