From 478d9d918a21969cf8a04bcccd482e12bca482a1 Mon Sep 17 00:00:00 2001
From: Daniel Chen <eggyrules@gmail.com>
Date: Thu, 7 Nov 2019 15:55:36 +0000
Subject: [PATCH] Update Unit 2: Biology.md
---
Grade 10/Science/SNC2DZ/Unit 2: Biology.md | 39 ++++++----------------
1 file changed, 11 insertions(+), 28 deletions(-)
diff --git a/Grade 10/Science/SNC2DZ/Unit 2: Biology.md b/Grade 10/Science/SNC2DZ/Unit 2: Biology.md
index d611868..1ff233f 100644
--- a/Grade 10/Science/SNC2DZ/Unit 2: Biology.md
+++ b/Grade 10/Science/SNC2DZ/Unit 2: Biology.md
@@ -51,7 +51,7 @@ A person contains roughly 100 trillion cells
- Is the control center of the cell
- Holds deoxyribonucleic acid (DNA) in form of `chromatin`
- DNA is a double helix containing genes
- - `Genes`: any section of DNA that contain a full set full set of instructions make either RNA or a protein
+ - `Genes`: any section of DNA that contains a full set of instructions to make either RNA or a protein, **found** in nucleus
- `Chromatin`: is DNA **wrapped tightly** in protein
- `Chromosomes`: are even more tightly wrapped `chromatin` used in cell division only, formed when `DNA` **condenses** in `mitosis`
- Surrounded by a double membrane
@@ -62,7 +62,7 @@ A person contains roughly 100 trillion cells
### Nucleolus
- Dense region of DNA located in the nucleus
- - This area of DNA is specially for ribosomal DNA (rDNA), or DNA used to code `ribosomes`, organelles that assemble proteins
+ - This area of DNA is specially for ribosomal DNA (rDNA), or DNA used to code `ribosomes`, enzymes that assemble proteins
- Produce "large" and "small" subunits of `ribosomes`, which either form complete `ribosomes` in `cytosol` or mix with `endoplasmic reticulum`, forming `rough endoplasmic reticulum` (RER)
### Cytoplasm & Cytosol
@@ -124,11 +124,8 @@ A person contains roughly 100 trillion cells
### Centrosomes
- Made of same protein as `cytoskeleton`
- - **Create and manipulate spindle* during mitosis in animal cells
- - One centrosome is a bound pair of two `centrioles`, one mother and one daughter centriole
- - Centrioles are present in very few types of plant cells
- - Centrioles **create** spindle during mitosis in both plant and animal cells
- - Centrioles do not manipulate spindle
+ - Crucial to mitosis in animal cells
+ - **Create and manipulate spindle fibres** during mitosis in animal cells
### Lysosomes
- Explained before.
@@ -207,27 +204,13 @@ A person contains roughly 100 trillion cells
- `Centromere`: Proteins sticking sister chromatids
- PMAT (prophase, metaphase, anaphase, telophase)
- Division of the nucleus
-- Prophase
- - Chromatin condenses into two identical `sister chromatids` which condense into `chromosomes`
- - Happens to 23 pairs of chromosomes
- - Nuclear membrane dissolves
- - Centrosomes move to opposite ends (`poles`) of cell, creating `spindle fibres` that begin to attach to `centromeres` in animal cells
- - Cell wall organises spindle in plant cell
-- Metaphase
- - Chromosomes line up in centre of cell to ensure they divide evenly
- - Everything in prophase has completed
-- Anaphase
- - Centromere splits
- - Sister chromatids are pulled towards opposite sides of cell via shortening spindle fibres
- - Sister chromatids now called `daughter chromosomes`
-- Telophase
- - Effectively opposite of prophase
- - Nuclear membranes form across each of the two nuclei
- - Daughter chromosomes unwind into chromatin and are no longer visible
- - Nucleolus forms in each nucleus
- - Spindle fibres break apart
- - **Cytokinesis** usually begins in telophase
- - Cell starts to **cleave** (cell centre starts to pinch itself)
+
+| Phase | Diagram | Description |
+| :--- | :--- | :--- |
+| Prophase | | - Chromatin condenses into two identical `sister chromatids` which condense into `chromosomes` <br> - Happens to 23 pairs of chromosomes <br> - Nuclear membrane dissolves <br> - Centrosomes move to opposite ends (`poles`) of cell, creating `spindle fibres` that begin to attach to `centromeres` in animal cells |
+| Metaphase | | - Chromosomes line up in centre of cell to ensure they divide evenly <br> - Everything in prophase has completed (e.g., nuclear membrane has dissolved completely) |
+| Anaphase | | - Centromeres split, separating sister chromatids <br> - Sister chromatids are pulled towards opposite sides of cell via shortening spindle fibres <br> - Sister chromatids are now called `daughter chromomsomes` |
+| Telophase | | - Effectively opposite of prophase <br> - Nuclear membranes form across each of the two new nuclei <br> - Daughter chromosomes unwind into chromatin and are no longer visible <br> - Nucleolus forms in each nucleus <br> - Spindle fibres break apart <br> - **Cytokinesis** usually begins in telophase <br> - Cells starts to **cleave** (cell centre starts to pinch itself) |
### Cytokinesis
- Cell division