Biology Notes for Exam

## Organelles within a Cell

### Typical Animal Cell

Nucleus: Kind of like the brain of the cell, contains DNA and controls activities within the cell.

Cytoplasm: Holds everything together, where most chemical reactions occur, the jelly like substance that fills the cell.

Mitochondria: Performs respiration

Ribosome: Carries out protein synthesis

Cell Membrane: Keeps unwanted stuff out, Brings wanted stuff in

### Plant Cell

On top of everything in an animal cell:

Cell Wall: A rigid structure on the outside of the cell to protect it and act as a skeleton

Vacuole: Manages waste, contains cell sap, holds other substances

Chloroplast: Allows for the plant to photosynthesise:

## Hierarchy of organisms

There are two main types of organisms:
Unicellular; Able to sustain itself and made up of only one cell
Multicellular; Made of many different types of cells that serve different functions

The hierarchy of organization only applies to Multicellular organisms:

From lowest to highest:

* Cells; the building blocks of life, and the smallest unit of it
* Tissues; groups of cells that make up the organs
* Organs: Made of said tissues, perform different functions
* Organ systems: Made up of organs that perform similar functions
* Organisms: Made up of everything prior

## MRS C GREN

MRS C GREN is an acronym for the different processes of life. These processes help scientists determine if something is living or not. The processes are:

* Movement: Can it move around independantly?
* Respiration: Can it produce and release energy through glucose and oxygen?
* Sensitivity: Can it sense its environment and changes to it?
* Cells: Is it made up of cells?
* Growth: Can it grow through nutrients?
* Reproduction: Can it make more of itself?
* Excretion: Can it remove harmful waste?
* Nutrients: Can it take in nutrients to grow?

## Types of Reproduction

**Note: This was taken directly from a ChatGPT chat**

### Mitosis

Mitosis is a type of cell division that occurs in somatic (body) cells of multicellular organisms. Its primary purpose is to produce two genetically identical daughter cells, each with the same number of chromosomes as the parent cell. Mitosis is responsible for growth, tissue repair, and asexual reproduction in some organisms. It consists of several stages: prophase, metaphase, anaphase, and telophase.

### Meiosis

Meiosis is a specialized type of cell division that occurs in the reproductive cells (gametes) of sexually reproducing organisms. Its primary function is to reduce the chromosome number by half and introduce genetic diversity among the offspring. Meiosis involves two sequential divisions: meiosis I and meiosis II. Meiosis I reduces the chromosome number from diploid (2n) to haploid (n), and meiosis II further divides the haploid cells without changing the chromosome number.

### Binary Fission

Binary fission is a simple form of cell division that occurs in single-celled organisms like bacteria and archaea. In this process, a single cell replicates its DNA and divides into two identical daughter cells. It's a form of asexual reproduction.

### Spore Formation

Certain organisms, such as fungi, algae, and some plants, reproduce through the formation and release of spores. Spores are small, often single-celled reproductive structures that can develop into new organisms under favorable conditions.