diff --git a/Grade 10/Science/SNC2DZ/Unit 2: Biology.md b/Grade 10/Science/SNC2DZ/Unit 2: Biology.md index ad5ecee..8fecdb2 100644 --- a/Grade 10/Science/SNC2DZ/Unit 2: Biology.md +++ b/Grade 10/Science/SNC2DZ/Unit 2: Biology.md @@ -44,25 +44,24 @@ A person contains roughly 100 trillion cells - Allows nutrients to enter - Allows waste products to leave - Surrounds and holds other organelles in cell -- Interact with outside chemicals (e.g., hormones) +- Interact with outside chemicals (e.g., hormones) ### Nucleus - Holds deoxyribonucleic acid (DNA) in form of `chromatin` - - DNA is a double helix that make genes - - `Genes` are a complete set of instructions to make a complete product (typically proteins) - - `Genes`: one of the many sets of instructions, in your DNA, found on a **chromosome**, for making a functional product (mostly proteins) + - DNA is a double helix containing genes + - `Genes` are a full set of instructions in DNA to make either RNA or a protein - `Chromatin` is DNA wrapped tightly in protein - `Chromosomes` are even more tightly wrapped chromatin used in cell division only - Surrounded by a double membrane - Substances enter and exit the nucleus via nuclear pores - Messenger RNA (mRNA) is encoded from DNA and sent to `ribosomes` to produce proteins +- Humans have ~2 m of genes per cell per nucleus tightly wrapped ### Nucleolus - Dense region of DNA located in the nucleus - This area of DNA is specially for ribosomal DNA (rDNA), or DNA used to make ribosomes - Produce "large" and "small" subunits of ribosomes, which either form complete ribosomes in cytosol or mix with endoplasmic reticulum, forming rough endoplasmic reticulum (RER) - - Is *not* surrounded by a membrane, literally is just same as rest of nucleus but denser ### Cytoplasm & Cytosol - `Cytosol` is the fluid cells contain @@ -72,101 +71,70 @@ A person contains roughly 100 trillion cells ## Endoplasmic Reticulum - The endoplasmic reticulum is a network of tubules and flattened sacs with a "rough" appearance because of the presence of `ribosomes` on the surface - Network of tubules and flattened sacs -- **Transport** proteins via cytoskeleton in vesicles +- **Transports** proteins via cytoskeleton in vesicles -## Rouch Endoplasmic Reticulum +## Specific to Rough ER - Appears "rough" due to the `ribosomes` attached to its outer surface - Located directly adjacent and attached to nucleus - Located next to `Golgi apparatus` -- `Ribosomes` in rough ER synthesize proteins - - Only specific proteins are synthesized by ribosomes of rough ER - - Proteins synthesized in `ribosomes` of rough ER are always sent to either `Golgi apparatus` via `vesicles` or stay in `rough ER` - - `Ribosomes` attach to and leave the `rough ER` regularly +- `Ribosomes` in rough ER **synthesize proteins** + - Transports synthesized proteins to `Golgi apparatus` for packaging and distribution - About half the cell's proteins are produced here -- **Modify, fold, and fix proteins** +- Folds, fixes and **modifies both newly-created and pre-existing proteins** somewhat like **proof-reading** -### Functions -- **Protein synthesis** - - About half of the cell's proteins are made here, by the `ribosomes` -- **Protein movement** - - Proteins are transported by vesicles throught the cell to other organelles, like the `golgi apparatus` -- **Protein "Proof-Reading"** - - pre-existing proteins can enter the `rough-ER` for **modification** - -## Smooth ER +## Specific to Smooth ER - Does not synthesize proteins - Appears "smooth" due to lack of `ribosomes` - Located directly adjacent and attached to nucleus - Synthesizes lipids (fats, e.g., cholesterol) - Metabolises carbohydrates -## Golgi Apparatus (Golgi Complex) -- **Receives, modifies and transports** proteins that were produced by the `rough-E.R` +## Golgi Apparatus +- Also known as Golgi body, Golgi complex, etc. +- **Receives, modifies and transports** proteins that were produced by the rough ER - **Packages** proteins into `vesicles` and sends them `cell membrane` for export ## Lysosome -- `White blood` cell uses the cytoskeleton to reach out and swallow up a bacterium, then uses `lysosomes` to break it down -- Spherical vesicle that contains `enzymes` -- Digests and kills foreign matter which is then excreted -- Digests and breaks down old and unused material to be recycled -- Digests and breaks down old or non-functional organelles as needed -- Only plays a very minor role in cell suicide (`apoptosis`) -- If lysosome does rupture (accidentally) everything dies +- Spherical vesicle that containing `enzymes` +- **Digests and kills** foreign matter which is then excreted + - E.g., white blood cells use lysosomes to kill bacteria then spit it out +- **Digests and breaks down** old and unused material/non-functional organelles as needed +- If lysosome ruptures everything dies, hence they are known as "suicude sacs" -### Functions -- **Digestion** - - Food or foriegn matter (invaders) are swallowed up and executed -- **Recycling** - - When an organelle "dies" `lysosomes` will recycle the dea material back into raw materials cellular suicide -- **Cellular suicicde** - - This is not good for the cell (obviously, but it is good for us. (E.g reasons why most of us don't have web feet/hands) - -## Midtochondria - - **Plural is "mitochondria"** +## Mitochondria + - **Singular form is "mitochondrion"** - Contains an inner and outer membrane - Processes glucose + oxygen gas to form carbon dioxide + adenosine triphosphate (ATP) - ATP allows proteins to do things (e.g., spend 1 ATP break 1 molecule) - ATP cannot be stored - - Mitochondria have their own DNA ## Cytoskeleton -- The cytosekleton **is** the skeleton of the cell, found in the `cytosol`, made up of protein. -- The cytoskeleton is also like the muscular system, able to change teh sahpe of cells in a flash - Made of protein filaments - Maintains and changes cell structure, much like a human skeleton + muscular system - Moves cells + - Modifies and adjusts cell structure as needed - Chemicals can travel along cytoskeleton, e.g., organelles, vesicles, etc. -## Organelles Specific To Animal Cells -1. centrioles and centrosomes -2. lysosomes +## Organelles specific to animal cells -### Centrioles and Centrosomes -- Involved in the process of cell division for animal cells, plant cells **DO NOT** use centrioles +### Centrioles and centrosomes - Made of same protein as cytoskeleton - A centrosome is a pair of centrioles - - Very important to cell division - - Split chromosomes apart after DNA has been replicated into daughter cells - - Helps regulate cell division + - Important to cell division in animal cells - Create cilia and flagella (e.g., small hair-like things that swipe dirt out of lungs and tails of sperm, respectively) ### Lysosomes -- Present in all animal cells but not present in the cells of most plants -## Organelles Specific To Plant Cells -1. Cell wall -2. Chloroplast -3. Central Vacuole +## Organelles specific to plant cells ### Cell wall - Provides structure and prevents cell rupture - Can be tough, flexible, and/or rigid -- Permeable to small molecules - Made of cellulose (type of sugar) - Also present in most bacteria, fungi, and protists ### Chloroplast -- The `solar panel` of the plant cell. +- The `solar panel` of the plant cell - Conducts photosynthesis - All chlorophyll is located in chloroplasts - Looks green @@ -175,15 +143,37 @@ A person contains roughly 100 trillion cells - Extremely large, may take up to 90% of volume in cell - Contains water - Maintains `turgor` pressure against cell wall (pushes against cell wall in all directions) -- **Provides the cell with shape** - - - - - - - +- Maintains cell shape and resistance + - Plant cells that lack turgor pressure (e.g., celery left in fridge) become flaccid +## Cell division +### Purpose +#### Growth + - Cells have maximum size before transportation of substances within cell becomes inefficient + - Cells transport chemicals (e.g., nutrients) via `diffusion` +#### Reproduction + - Single-cellular organisms reproduce via division asexually + - Multicellular organisms reproduce via combining two germ cells ("sex cells") that contain half the DNA each of two organisms + - This is sexual +#### Repair + - Cells naturally die and need to be replaced + - e.g., red blood cells, hair cells, skin, injuries +### Cell cycle + - Interphase + - G1 + - S + - G2 + - Mitosis + - Occurs only in eukaryotic cells + - Prophase + - Prometaphase + - Metaphase + - Anaphase + - Telophase + - Cytokinesis + - G0 + - Cell no longer divides + - Outisde of cell cycle \ No newline at end of file