Week 1
Chapter 1:
Describe the scientific method. In what ways do you use the scientific method in everyday life?
The scientific method is a process for experimentation that is applied in exploring observations and answering questions. Thus, it is a series of methods followed by scientific investigators to answer specific questions regarding the natural world. The scientific method entails making observations, formulating a hypothesis, and conducting scientific experiments. Basically, a typical scientific inquiry begins with an observation that is followed by the formulation of a question regarding what has actually been observed. The following are the steps involved in the scientific method;
Observation
Question
Hypothesis
Experiment
Results
Iterate
The scientific method can be used in everyday life. For instance, I can get two slices of bread, put them into the toaster. I can then press the button. However, my bread does not actually toast. After making such an observation, I will ask myself a question as to why the bread did not toast. I could then make a hypothesis that the bread did not toast because the electrical outlet is broken. I will thereafter make a prediction regarding the outcome. I might predict that if the electrical outlet is broken, the problem can be fixed by plugging the toaster into a different outlet. I will then test the prediction by plugging the toaster into a different power outlet and see if the bread toasts. If the bread is toasted, the hypothesis is correct and the bread does not toast, the hypothesis is wrong. I will then reflect on the results and use them to guide my next course of action.
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Week 2
Chapter 2:
Give an example of each, monosaccharide, disaccharide, and polysaccharide.
Monosaccharide- glucose
Disaccharide- sucrose
Polysaccharide- cellulose
Chapter 3:
Which organelles are common to both plants and animal cells? Which are unique?
Structurally, plant and animal cells are very similar because they are both eukaryotic cells. The organelles that are common in plant and animal cells include;
Cell membrane
Cytoplasm
Nucleus
Endoplasmic reticulum
Ribosomes
Golgi apparatus
Mitochondria
Lysosomes
Vacuoles
There are organelles which are unique. They are either found in animal cells alone or in plant cells alone. The animal cell organelles not found in plant cells include;
Cilia and flagella
There are plant cell organelles which are not found in animal cells. They include;
The cell wall
Plastids
Central vacuole
Week 3
Chapter: 4 1. Name the four types of nitrogenous bases found in DNA.
Adenine
Guanine
Cytosine
Thymine
Describe the process of DNA replication.
When a cell divides, each of its double strands, of DNA, splits into two single strands. The process of DNA replication follows three steps: initiation, elongation and termination.
Initiation
The replication begins at a particular location in the double helix called “oriC” to which some initiator proteins bind and trigger unwinding. Enzymes called helicases unwind the double helix by breaking the hydrogen bonds between the complementary base pairs. The cell gets ready for the next stage by creating short sequences of RNA called primers. The primers provide a starting point for elongation.
Elongation
At this stage, a new DNA strand grows one base at a time, with the primer as the starting point. Basically, the existing strand becomes the template for the new strand. The elongation is controlled by the enzyme DNA polymerase. The elongation only occurs in the leading direction. The lagging strand unwinds in small sections that are replicated by the DNA polymerase in the leading direction.
Termination
This is the final stage of the DNA replication process. When the elongation completes, the new double helices will have replaced the original helix. During termination stage, the last primer sequence must be removed from the end of the lagging strand. As such, the enzymes snip off a telomere at the end of each replication. This leads to shorter strands after each cycle. Finally, enzymes known as nucleases then proofread the new double helix structures and remove mis-paired bases.
Week 4
Chapter 7
Explain why predation is a strong selective pressure
Predation is a strong selective pressure. It provides strong selective pressures on prey populations. It forces prey species to evolve better defenses against the predators. For instance, if a cheetah preys on an antelope, the antelope will evolve in a way that will help them to survive. Antelopes that face the threat of predation will be forced to enhance their speeds in order to escape being eaten by cheetahs. Therefore, predation is an important evolutionary force because selective predation natural selection in prey populations.
Week 5
After watching the documentary answer the following questions
What was your understanding of evolution before and then after watching the documentary?
The documentary has significantly widened my perspective of evolution. Initially, I thought evolution was only limited to human beings. My understanding of evolution revolved around monkeys and human beings. As such, I thought evolution refers to how monkeys changed over time to become human beings. However, after watching the documentary, I have realized that evolution is a wider concept that describes the change in the heritable characteristics of biological populations over successive generations. The documentary introduced me to new concepts like mutation, natural selection and genetic drift. I learnt that the processes of mutation, natural selection and genetic drift resulted in the change in the gene pool of biological populations from generation to generation. I have realized that evolution effected change in the characteristics of a species over generation and it heavily relies on the process of natural selection. Most importantly, I learnt that evolution is based on the idea that all species are related.
Provide an example of evolution covered in the documentary.
An example of evolution covered in the documentary involved the peppered moth. The example featured natural selection in action. According to natural selection, individuals that are most suited to their environment survive, and given enough time, they will gradually evolve. Before the industrial revolution, the peppered moth was most commonly a pale whitish color with black spots. Their color enabled them to hide from their predators on pale barks of trees. However, the rarer dark colored peppered moth was easily seen against the pale barks of trees by predators. After the industrial evolution, the air in industrial areas was full of soot. This stained trees and buildings black. As a result, the lighter moths became exposed to predators as they could easily be seen against dark barks of trees. This made the darker moths more common and the lighter ones rarer.
Week 6
Chapter 6:
Explain how the structure and arrangement of alveoli make them well suited for their role in gas exchange.
The purpose of the alveoli is to allow fast and efficient gas exchange between the blood and the lungs.
The alveoli are very thin in size. This helps to increase their surface area for gas exchange between the blood and the lungs. As such, more amounts of gases can be exchanged within a given time.
Alveoli are extensively surrounded by blood vessels. This ensures that more air can be exchanged within a given time.
The walls of alveoli are one cell thick. This allows gases to rapidly move through the walls.
What is the function of the loop of Henle, the collecting duct, and antidiuretic hormones in the urinary system?
Loop of Henle
The function of the loop of Henle is to reabsorb water and sodium chloride from the filtrate. It helps to conserve water for the organism and consequently produce highly concentrated urine.
Collecting Duct
The function of the collecting duct is to collect urine from the nephrons and moves it into the renal pelvis and ureters.
Antidiuretic Hormone
The function of the antidiuretic hormone is to constantly regulate and balance the amount of water in the blood. Therefore, the ADH maintains blood water balance.
Week 7
Chapter 6:
What is the difference between the endocrine glands and the exocrine glands?
The endocrine glands are ductless, pour secretion directly into the blood and they control long term activity of target organs. On the other hand, exocrine glands may or may not have ducts, secrete directly at the site of action and control short term activity.
List the four parts of a neuron, and explain each ones special function.
Dendrites – they collect signals from the axon terminals.
Axons- They relay information reliably and quickly from the senses to the central nervous system.
Axon terminals – They make the actual connection to other neurons.
Soma – it carries out the basic life processes of neurons.
Week 8
Chapter 8:
Plants have a very unique anatomy, what parts of the plant are male and what parts are female?
Male parts
Anthers
Filaments
Female parts
Stigma
Style
Ovary
Ovules
Chapter 9:
What stages of development occur before the fertilized egg reaches the uterus?
The zona pellucida breaks
The blastocyst is released
The blastocyst moves through the fallopian tube towards the uterus.
Week 9
Chapter 5:
Human cloning, is it ethical? Explain your reason for being for or against human cloning.
Human cloning is not ethical. There are non-ethical health risks related to cloning. Mutation of genes in the process of cloning is a likely tragedy. As such, the technique is very risky. There are also non-ethical emotional risks brought about by cloning. A child grows up knowing that her mother is her sister and her grandmother is actually her mother. Therefore, human cloning should not see the light of day.
Week 10
What was the most interesting informational fact you learned during the course lectures? And why?
There are various interesting informational facts that I encountered during the course of the lectures. One of the informational facts that stood out regards the process of DNA replication. I realized that the process is systematic and that there are hormones that play a significant role in the development of new DNA strands. Initially, I never imagined that the process of DNA replication is that interesting. In fact, I have resolved to explore all the issues surrounding DNA and cell division.
