HSC Biology Marathon 2015 (2 Viewers)

[Flop21]

Describe random segregation (/independent assortment [these are the same aren't they?]).

 

[BlueGas]

Describe random segregation (/independent assortment [these are the same aren't they?]).

Random segregation: This separation of chromosomes, also referred to as random segregation, ensures the chromosome number in the resulting gametes will be half that of the original cell.

Independent assortment: The paternal and maternal chromosomes sort themselves independently of each other.

For those that do Communication:

Explain the possible reasons for the differences in sound frequencies detected by humans and other animals. (4 marks)

 

[Khan.Paki]

From what I was reading, I don't think they are.

Random Segregation is when alleles create gametes, they segregate and each haploid gamete ends up with only one allele. As this is random, variation is inevitable.

Independent Assortment is when genes on chromosomes sort independently as they can line up many different ways, producing many gene combinations.

The main ideas are still cloudy. It would be great if someone could clear up on this.

 

[tfw english]

Explain the possible reasons for the differences in sound frequencies detected by humans and other animals. (4 marks)

Humans detect sound at a frequency range from 20- 20,000 Hz, this allows humans to effectively communicate, either through speech, or to issue warnings. Due to differences in environment, and the competition for resources, bats can perceive sound frequencies from 100,000 - 120,000 Hz. Because they are blind, this range of frequency allows them to detect very high sounds, allowing for precise echolocation of their prey. More so, marine mammals need to communicate over long distances, as such, whales can detect frequencies as low as 20 Hz, allowing them to detect sound from great distances. These differences between mammals detection of sound occur due to the environment they inhabit and the certain needs within these environments (food, communication).

 

[TQuadded]

Random segregation: This separation of chromosomes, also referred to as random segregation, ensures the chromosome number in the resulting gametes will be half that of the original cell.

Independent assortment: The paternal and maternal chromosomes sort themselves independently of each other.

For those that do Communication:

Explain the possible reasons for the differences in sound frequencies detected by humans and other animals. (4 marks)

In humans, we can detect frequencies that range from 0.02 kHz to 20kHz. A dolphin, however, can detect frequencies from 1kHz to 100kHz. This may be because humans produce sound within these limits for efficient communication. Additionally, high frequency sound waves are not able to travel very far in air, and hence its reception is not necessary for basic survival and communication. On the other hand, dolphins produce high pitched sound to be able to use echolocation as a detecting mechanism for predators and/or prey. Sound is also able to travel much further in water than in air, therefore requiring to be able to detect these high frequency sound waves for survival.

 

[Khan.Paki]

All of the notes I have all have different wavelengths for the same animal -.-

 

[Flop21]

Do we need to know the steps in the production of a transgenic species?

 

[BlueGas]

Do we need to know the steps in the production of a transgenic species?

I don't think you need to know too much anyway, just know that the desired gene is isolated, cut off, using particle guns and so on...

 

[tfw english]

Do we need to know the steps in the production of a transgenic species?

I think so, can't hurt. I've seen a few questions that you may need to know, just keep it basic anyway

Edit: What BlueGas said ahaha

 

[Queenroot]

All of the notes I have all have different wavelengths for the same animal -.-

Are they perhaps in different units?

 

[tfw english]

Describe two processes that ensure genetic diversity in sexually reproducing natural populations. (2)

OR

The two research teams of Watson and Crick and Franklin and Wilkins were both aiming to discover the
structure of DNA.

Assess the contributions of both research teams to the discovery of the structure of DNA. (5)

 

[Mr_Kap]

A standard NSW vaccination schedule for diptheria/pertussis/tetanus (DPT) is shown:

Age: 2 months, 4 months, 6 months, 18 months, 4 years.

Propose reasons for the frequent vaccination between 2 months and 4 years. 4 MARKS

 

[BlueGas]

Quick question, what's the depedent and indepdent variable of an experiment? I've read so much different things I don't know which variable is the one you can change/control.

 

[Flop21]

What form are lipids carried in and what they are carried by?


(sorry I didn't answer the previous questions, will later, just I actually want to confirm the answer for ^

 

[Flop21]

Quick question, what's the depedent and indepdent variable of an experiment? I've read so much different things I don't know which variable is the one you can change/control.

Cows Moo Softly

In Deep Clover


Top row is, Change, Measure, Same.

Bottom row is, Independent, Dependent, Control.

They all match up respectively, e.g. change = independent, measure = dependent.... etc.


I write this up quickly to confirm which one is which lol.

 

[TQuadded]

Describe two processes that ensure genetic diversity in sexually reproducing natural populations. (2)

OR

The two research teams of Watson and Crick and Franklin and Wilkins were both aiming to discover the
structure of DNA.

Assess the contributions of both research teams to the discovery of the structure of DNA. (5)

Q1.
Two processes contribute to genetic diversity in populations. One of which is crossing-over of the genes between homologous pairs in the Prophase I stage, increasing the randomness of the results of the final four daughter cells. Another is random segregation where any chromatid can end up in any gamete cell, which also increases the variation between the final outcome of the process of meiosis. These two processes therefore increase genetic biodiversity and variation within natural populations through sexual reproduction.

 

[Mr_Kap]

What form are lipids carried in and what they are carried by?


(sorry I didn't answer the previous questions, will later, just I actually want to confirm the answer for ^

Lipids are transported as chylomicrons which are clusters of triglycerides, phospholipids and cholesterol, wrapped in a coat of protein.
These are released into the lymph and eventually pass into the veins.

Learn this definition word for word. Its from ahmad shah notes. I just wrote it now...should be the same (if i memorised it correctly)

 

[BlueGas]

Lipids are transported as chylomicrons which are clusters of triglycerides, phospholipids and cholesterol, wrapped in a coat of protein.
These are released into the lymph and eventually pass into the veins.

Learn this definition word for word. Its from ahmad shah notes. I just wrote it now...should be the same (if i memorised it correctly)

Yeah it's word for word, except you forgot the brackets

 

[tfw english]

Explain why the concentration of water in cells should be maintained within a narrow range for optimal function. (3)

 

[BlueGas]

Explain why the concentration of water in cells should be maintained within a narrow range for optimal function. (3)

Living cells work best in an isotonic environment, where the concentration of solutes inside the cell is the same as outside the cell. Any change to the concentration of solutes will result in a change in the levels of water and will lead to death.