Y10 Biology - General Definitions

Cells

basic structural and functional unit of life

Life

All living organisms, which are composed by one or more cells, carry out neccessary biological processes (e.g. MRS GREN).

Prokaryotic Cells

simple, single-celled organism that lacks a membrane-bound nucleus and organelles; e.g. bacteria and archae

Prokaryotic Cells

a complex organism made of cell(s), that has a membrane-bound nucleus and organelle; e.g. protists, fungus, animal, and plants.

Plant Cell

A type of eukaryotic, autotropic cell that has a rigid cell wall, chloroplasts for photosynthesis, and large vacuoles for storage, geared to produce its own food.

Animal Cell

An animal cell is a complex eukaryotic, heterotropic cell that has a membrane-bound nucleus and organelles, and is typically more flexible and varied in shape compared to plant cells.

Hierachy of Components of Multi-cellular Organisms

Organism → Organ System → Organ → Muscle → Cell —> Organelles → nuclues → Chromosomes → DNA → Gene/Alleles

(Plasma) Membrane → found in both animals & plants

a membrane made of two layers of phospholipids that encloses the content of a cell

Cell Wall → found in plants

a structurally sound and rigid outer layer, outside the cell membrane

Cytosol → found in plants & animals

the gelatinous liquid inside the cell, containing important nutrients, such as sugars, salts, minerals, amino acids, etc

Cytoskeleton → found in plants & animals

provides structure and helps to control movement in and out of the cell

Nucleus → found in plants & animals

surrounded by a bilayer of nuclear membrane, it is responsible for controlling and coordinating cellular activities and storing the majority of genetic material (code) of the cell.

Genetic Material → found in plants & animals

the hereditary substance in the cell that carries all the information specific to an organism; can be organised as either DNA or RNA

Chromosomes → found in plants & animals

lengths of a DNA molecule that is found in the nucleus, containing the genetic information of that organism

Ribosomes → found in plants & animals

A non-membrane-bound organelle involved in the synthesis of proteins, using the DNA information (genetic code).

Endoplastic Reticulum → found in plants & animals

Holds the ribosomes close to the nucleus, and wraps a newly formed protein in a bubble for transport out of the cell

Rough Endoplasmic Reticulum → found in plants & animals

Contains ribosomes that synthesis protein, to modify and transport them within the cell

Smooth Endoplastic Reticulum → found in plants & animals

synthesises lipids and transports them within the cell

Golgi Apparatus → found in plants & animals

site of secondary manufacturing of protein, by wrapping themself in a protective bubble for transport of the cell

Mitochondria

a small, oval-shaped organelle that is found scattered throughout the cytosol of a cell, the number of which is dependent on the energy requirements of that cell; it is the site of aerobic cellular respiration, where there’s a series of chemical reactions to gain A.T.P. (energy).

Chloroplasts → found in plants

An oval-shaped organelle with a double membrane, comprising a grana (stacks of thylakoids) and stroma (fluids), enclosing the organelle; it is the site of photosynthesis, which the green pigment called chlorophyll supports via absorbing light energy and makes it available to assist in photosynthesis.

Vesicles → found in plants & animals

the packets of the cell, containing food, nutriention, “waste,” or products required

Vacuole → found in plants & animals

Very large storage compartment, containing water (mostly) and sugars, also providing structure; note that plants have very large vacuoles, whereas animals have smaller ones.

Linear Chromosomes

Garnered towards Eukaryotic Cells

Circular Chromosomes

Garnered to more of Prokaryotic Cells

Genetics

the study of inheritance, specifically on how characteristics are passed down from one generation to another

Hereditary

Genetically Determined characteristics → genes and traits that are passed from generation to generation

Genetic Variation

small changes in the gene’s code that makes an organism unique

Genotype

A set of genes that determine a singular trait

Phenotype

the observable, physical characteristics of an organism, dependent on the genotype(s) and environment.

Deoxyribose Nucleic Acid (DNA)

Genetic Material that is passed on from one generation of organism to another, that is found in the nucleus, specifically the nucleolus, in every cell (except for RBC)

Properties of DNA

• Able to make copies of itself

• carries genetic information to make protein

Subunits of DNA

Nucleotides, that are composed of the nitrogenous base, deoxyribose sugar molecule (the backbone of the structure), and phosphate molecule

4 Types of the Nitrogenous Base

Adenine, Guanine, Cytosine, Thymine

Complementary Bases

the nitrogenous bases that always pair together:

• Adenine & Thymine

• Guanine & Cytosine

DNA is comprised of…

2 strands attached via