BIOLOGY REVISION

本站添加: 2026-05-07

[00:00:00]Welcome to this uh platform. So, today's biology revision, we're going to answer two questions, and these two questions are coming from two different topics, as you can see with me. So, the first question is coming from cell specialization, and the second question is coming from uh saprophytic nutrition.

[00:00:16]Okay, so we are going to handle two topics at once. Okay, so let us start with the first one, which is a a question from cell specialization. Now, this is not the first time we are answering a question from the topic cell specialization. We've had uh a lot of questions that we've answered in the past, but let us look at the what we have uh here.

[00:00:35]So, the question reads, "Figure 1.1 and 1.2 shows specialized cells. Figure 1.1 and 1.2 shows specialized cells." So, as you can see, figure 1.1, figure 1.2. Very important that you understand these things.

[00:00:53]Now, most cases when you are given such a question, the first thing you identify is either you're identifying the parts of the cell. So, let us look at the first question. So, "Identify the cell labeled F in figure 1.2." So, in other words, they want you to identify this cell.

[00:01:10]Okay, so what is the cell in figure 1.2?

[00:01:15]So, this cell is otherwise known as the um phagocyte.

[00:01:23]Phagocyte.

[00:01:25]And of course, it's the white blood white blood cell. I'm avoiding to label it as white blood cell because white blood cell we have also another type, which is um uh we have the phagocyte, and of course, uh the lymphocytes. Okay? So, this one is the phagocyte, white blood cell. So, you write phagocyte. Now, what makes you identify this cell? That is the second question. "Which feature in diagram enables you to identify cell F in A1 above?" So, this cell, after saying it's the white blood cell or it's the phagocyte, what feature made you identify? So, what made us identify this one is because of its nucleus, which is robed nucleus. So, here the answer is the robed nucleus. So, that's that is what makes us to identify as the phagocyte white blood cell.

[00:02:24]Then, let us go to question B.

[00:02:27]That is B1. "In figure 1.1, this one, shows a group of similar cells.

[00:02:33]What term is used to refer to such a group?" So, a group of similar cell is known as tissue.

[00:02:42]So, you're referred to as what? Tissue.

[00:02:44]What about the group of similar uh I mean, the group of uh yeah, similar cells? What about the group of tissue?

[00:02:51]What about the group of So, you need to know about organization.

[00:02:55]Okay?

[00:02:57]Coming to two of B, "Suggest a region in human body where figure 1.1 is found."

[00:03:04]So, where is the um And by the way, this is uh these are ciliated cells.

[00:03:12]So, where is or where are these cells found? So, one, in the respiratory tract, and also in the oviduct, that is in the female.

[00:03:22]And also, you need to know the functions of these um cells in the region where they are found. For example, in the respiratory tract, they sweep out uh mucus containing dust and germs.

[00:03:34]In the oviduct, they move or they move the ovum toward the the uterus. Okay?

[00:03:40]So, make sure that you know even uh the function. Sometimes the question comes, "What is the function of the cell?"

[00:03:49]Then, coming to say uh to to question C, "State the three specialized cells in plants."

[00:03:55]State three specialized cells in plants.

[00:03:58]Now, since we are looking at specialized cells, these are not only specialized cells, there are about quite a number of specialized cells. Okay? So, you need to know at least uh all of them. Now, before we come to this question, there's another thing that you need to understand. As you can see there on top, these things on top, hair-like, this is what you call cilia. Okay?

[00:04:21]Called what? Cilia. Now, what is the function of that? So, it's the one that beats or move in order to to sweep out um mucus containing dust and germs. So, sometimes you're given a question to give the function of the part labeled E.

[00:04:38]So, the part labeled E simply uh sweep out mucus uh containing dust and germs. Okay?

[00:04:46]So, very important that you understand that. Now, let us come back to the question. "State three specialized cells in plants." So, specialized in uh cell in plants, you can talk of the xylem.

[00:04:57]We can talk of the phloem.

[00:05:00]We can talk of what? Um We can talk of uh the guard cell or palisade cell and ovules. So, aside from that now, after giving these, you might be asked the question to give the function of one of these. So, you need to know the function of the xylem, which is simply conduction of water and mineral salt. Then, phloem uh transport manufactured food. Then, guard cell regulate the um size of the what? Of the stomata. So, make sure that you know uh the specialized cells and their functions, where they are found, and their adaptations. So, make sure that you do that. Okay, so this is what we can uh answer on this uh question. Normally, question such as this one comes in paper two biology, and uh the question, the whole of it is nine marks or eight marks. So, just like that, you have marks uh or you have nine marks. So, very important that you understand this topic. I keep on emphasizing.

[00:06:02]Let us look at the second question. This is coming from saprophytic nutrition. We know what saprophytic nutrition is.

[00:06:08]Okay? Kind of nutrition that involves uh organism feeding on dead uh decaying matter.

[00:06:16]So, let us read the question.

[00:06:18]"Figure two shows the structure of the fungus."

[00:06:22]As you can see here.

[00:06:24]But of course, you're going to look at examples of fungus. I guess that question is here.

[00:06:28]So, "Identify." So, when you're given such a diagram, always or usually, the first question is identifying the parts.

[00:06:35]So, you need to make sure that under saprophytic nutrition, you know the diagram here, and you'll be able to identify the parts or know the parts of the whole of this. "So, identify the parts labeled D and G." So, which one is the part labeled G? I mean, D. The part labeled D is this end part, which is known as the sporangium, plural sporangia. So, it's just the sporangium.

[00:07:01]This is one.

[00:07:02]Then, what about E? Even if we are not given a question to identify, that is the sporangiophore.

[00:07:08]Sporangiophore, like that.

[00:07:11]Then of course, we can identify this one as the stolon, which is E. Then of course, this G is the rhizoids. Even if you are given a question to give the function, you can't give a function of the parts that you do not know. So, make sure that the first thing, identify the parts. So, these are known as what?

[00:07:28]Spores.

[00:07:29]Okay.

[00:07:32]"So, identify the parts D and G." So, already we can just pick from what we've uh written there. So, D is a sporangium, then of course, G is the uh rhizoid.

[00:07:44]"Explain the function of the parts." So, after identifying the parts, make sure that you know the functions of each.

[00:07:51]So, "Explain the function of E and F."

[00:07:55]So, let us start with the function of D, which is the sporangium. The sporangium bears spores. So, the function of this one simply to bear spores. So, it bears what? It bears spores.

[00:08:07]Then, this one holds the sporangium at the end. Okay? So, support or holds the sporangium at the end. Okay? So, that is the function of the sporangiophore.

[00:08:20]Then, the spores germinate into new organism when conditions permit.

[00:08:25]Okay?

[00:08:27]Then, stolon grows along uh substrate.

[00:08:31]Then for this one, it produces extracellular enzyme, also known as the feeding hypha.

[00:08:36]So, produces extracellular enzymes.

[00:08:40]And also, uh it's a feeding hypha.

[00:08:43]So, I guess I've answered these questions. So, function of E and F, so what is E? E is sporangiophore, so holds the sporangium at the end. Then, this one uh grows along the what? Along the substrate.

[00:08:58]Then, question C. So, this one is two marks.

[00:09:02]Just this, just two marks. Also, this one, two marks. So, already we have four marks.

[00:09:07]"Then, outline the process of the nutrition carried out by the fungus in figure two." So, this question is normally three marks.

[00:09:15]Now, this question, another way to phrase this question can be, "Explain how saprophytic nutrition is brought about." So, we know that the kind of nutrition that is here is saprophytic nutrition. We must have found a question where they ask us to identify the kind of nutrition. If it's not there, one of the questions that you expect is identifying the kind of nutrition it carries out.

[00:09:35]So, that is known as saprophytic nutrition. And like I've said from the start, sometimes you're asked to to to to define saprophytic nutrition. So, just a kind of nutrition uh where organism feeds on dead decay uh matter.

[00:09:47]So, how is it brought about? So, the way it is brought about is that these saprophytes releases extracellular enzymes from their rhizoids. So, the first thing it involves the secretion of extracellular enzymes. So, you're explaining this part. So, outline the process of nutrition carried out by the fungus in figure two. So, it involves the secretion of extracellular enzymes. Now, the extracellular enzymes hydrolyze the substrate in which they are growing, and they absorb these same rhizoids absorb the end product of digestion uh into or the end product of digestion are absorbed by the fungus. So, what did I say?

[00:10:30]So, to answer this question, you just say it involves secretion of extracellular enzymes.

[00:10:38]Extracellular enzymes hydrolyze the substrate in which the uh the fungus is growing.

[00:10:45]The end product of digestion of substrate is absorbed by the fungus. So, that is what you needed to write here to get uh three marks.

[00:10:55]Then B of C, give an example of a fungus that carries out the process of the nutrition shown above. So, this diagram can be the diagram of So, examples of fungus that carries out Here, you can talk of uh uh Mucor. I don't know how you pronounce this one, but Mucor.

[00:11:15]Then also, you can talk of uh Rhizo- Rhizopus. Okay? So, these are two examples that we can put.

[00:11:24]Okay. So, this is what you expect. And of course, make sure that you do look at uh some more questions um on this particular part. It doesn't It doesn't just end there. So, you need to make sure that you look at Let's say um the importance of uh the saprophyte in nature.

[00:11:42]So, in nature, these saprophytes helps in the recycling of uh nutrients and also um hydrolyzing uh a dead body or elimination of dead bodies.

[00:11:55]Then also, it has another function, which is What is the function uh What is the the the the use of these? So, these can also be used as food, for example, mushroom. Okay? So, I guess you've gotten. And also, in baking and brewing, such as yeast. So, those are the function or importance of these in nature. And I guess you've gotten the whole of it. So, this is what I wanted us to uh revise, and I guess it has been beneficial.

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