HSC Biology Question Thread

[imtrying]

Mendel actually did several experiments not just those 2. They were
Pea Shape (smooth or wrinkled)
Pea Colour (yellow and green)
Pea Pod Colour (Yellow and green)
Pea Pod Shape (Smooth or constricted)
Stem Length (tall or short)
Flower Colour (white or pink)
Pea/Flower (not too sure of which one) positioning (Axial [along the whole stem] or Terminal [just the top])

If asked to outline his experiment you would choose on of the traits, preferably the one you know the best. Then proceed to describe the experiment. Always do what you know best if it was what you were taught. You don't need to stress about knowing all 7 traits but knowing the experiment and knowing which trait was dominant and recessive should suffice.

Hope this helps

Thank you!! This helps heaps:)

[kevin217]

For dependent variable is "characteristics of microbe colony growth on agar plate" an acceptable answer?
Also could you guys explain what the control would be? My excel book says "Temperature/volume medium" so I think they are getting it mixed up with controlled variables. The Bostes answers say "sterilised water" which I'm not exactly too sure why.

[Skidous]

For dependent variable is "characteristics of microbe colony growth on agar plate" an acceptable answer?
Also could you guys explain what the control would be? My excel book says "Temperature/volume medium" so I think they are getting it mixed up with controlled variables. The Bostes answers say "sterilised water" which I'm not exactly too sure why.

For dependent variable you would be looking at microbial growth in general not necessarily the characteristics of it.

The control for this experiment would be sterilised water as you want to confirm whether or not the agar plates were contaminated.

What your textbook described was a controlled VARIABLE and not a controlled experiment where no independent variable is added (sterilised water would not promote microbial growth)

Hope this helps

[kevin217]

For dependent variable you would be looking at microbial growth in general not necessarily the characteristics of it.

The control for this experiment would be sterilised water as you want to confirm whether or not the agar plates were contaminated.

What your textbook described was a controlled VARIABLE and not a controlled experiment where no independent variable is added (sterilised water would not promote microbial growth)

Hope this helps

Thanks for the insight. But for the control, you said it is to confirm whether or not there are contaminants on the agar plate that produce microbes. Could an agar plate just by itself be a control as well?

[Skidous]

Thanks for the insight. But for the control, you said it is to confirm whether or not there are contaminants on the agar plate that produce microbes. Could an agar plate just by itself be a control as well?

Yes it could be, but since this question asks about food or water it'll be easier to use one of those that has no bacteria.

(Also to express control experiments its to show what the independent variable does within the experiment (which then produces the dependent variable) and then allows for comparison)

[aimbotted]

skidoos! talking about meiosis can you help me out with this question?

[Skidous]

skidoos! talking about meiosis can you help me out with this question?

You would need to draw all the different types of daughter cells

EBG/EBg/EbG/Ebg

Each of these have equal opportunities to be daughter cells so their expected frequency should be 1/4 for each

This is because each of these pairs have 4 chromatids and this have a 2/8 chance of becoming gametes and hence an expected frequency of 1/4

[Justina Shehata]

What are the sizes of the red and white blood cells and the units we measure them in?

[kevin217]

What are the sizes of the red and white blood cells and the units we measure them in?

They're measured in micrometres (μm). Red blood cell is approx 6-8 μm and white blood cells are approx 10-12 μm

[Skidous]

What are the sizes of the red and white blood cells and the units we measure them in?

Red Blood Cells (RBC) are approximately 8 micrometers

White Blood Cells (leukocytes) are 12-15 micrometers

Don't forget about the biconvex shape of RBC

[Skidous]

They're measured in micrometres (μm). Red blood cell is approx 6-8 μm and white blood cells are approx 10-12 μm

White blood cells (more specifically neutrophils which make up 70% of the white blood cells in our body) are 12-15 μm

[kevin217]

White blood cells (more specifically neutrophils which make up 70% of the white blood cells in our body) are 12-15 μm

I guess so but I was taught WBC were 10-12 μm

[melprocrastinator]

Hey, i have a contradicting set of notes. The ones i wrote earlier this year, have that the blood becomes de-oxygnated at the Kidney, but my other sets says there is an increase of oxygen in the blood around the kidney...
see my problem, which one is correct??

THANK YOU x

[lha]

How many pages should you be writing for 7 and 8 markers in the exam? I know in the core topic, it gives you one page usually for the 7/8 marker but usually for all of the questions you need more lines, so how many pages is the optimal number? Also for the option topic, where there is no line indication, how many pages should we write for the long responses?

[kevin217]

Hey, i have a contradicting set of notes. The ones i wrote earlier this year, have that the blood becomes de-oxygnated at the Kidney, but my other sets says there is an increase of oxygen in the blood around the kidney...
see my problem, which one is correct??

THANK YOU x

Oxygen levels in blood will decrease after it passes the kidney. Your first set of notes are correct. According to my notes, carbon dioxide is the only chemical that increases after blood passes through the kidney.