From ca49a56ca7e8eb745b0c96164b936a9a4692d390 Mon Sep 17 00:00:00 2001 From: Daniel Chen Date: Thu, 24 Oct 2019 23:03:55 +0000 Subject: [PATCH] Update Unit 2: Biology.md --- Grade 10/Science/SNC2DZ/Unit 2: Biology.md | 37 ++++++++++++++++++---- 1 file changed, 31 insertions(+), 6 deletions(-) diff --git a/Grade 10/Science/SNC2DZ/Unit 2: Biology.md b/Grade 10/Science/SNC2DZ/Unit 2: Biology.md index dc585f2..a28b4de 100644 --- a/Grade 10/Science/SNC2DZ/Unit 2: Biology.md +++ b/Grade 10/Science/SNC2DZ/Unit 2: Biology.md @@ -1,18 +1,18 @@ # Unit 2 Biology - Tissues -- Organs, +- Organs - Systems of living things -## Celular Biology -A person contains roughly 100 tillion cells -- Cells are roughly 20 $`\um`$ (micrometer, $`10^{-6}`$ m), around 250 cells / cm +## Cellular Biology +A person contains roughly 100 trillion cells +- Cells are roughly 20 `\um` (micrometer, $`10^{-6}`$ m), around 250 cells / cm ## Cell Theory 1. All living things are composed of cells 2. Cells are the basic units of living organisms 3. All cells came from pre-existing cells -## Types Of Cells +## Eukaryotic versus Prokaryotic Cells `Prokaryotic cell`: Meaning before/lacking nucleus `Eukaryotic cell`: Means complete nucleus @@ -22,5 +22,30 @@ A person contains roughly 100 tillion cells |DNA|In nuclear region|Usually in membrane, bound nucleus| |Size|Usually smaller|Usually larger| |Organelles|Not membrane-bound, smaller|Membrane-bound, more complex| -|Organization|Usually single-celled|Often multicelled| +|Organization|Usually singlecelled|Often multicelled| |Metabolism|May not need oxygen|Usually needs oxygen to exist| + +## Cellular Organelles + +### Cell Membrane + - Controls what substances enter/leave the cell selectively + - Allows nutrients to enter + - Allows waste products to leave + - Surrounds and holds other organelles in cell + +### 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) + - 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 + +### Nucleolus + - Dense region of DNA located in the nucleus + - This area of DNA is specially for ribosomal DNA (rDNA) + - Produce "large" and "small" units of complete ribosomes, which either remain free 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 +