Human fertilisation and early development
Description

Overview of fertilisation and early human development. From conception leading to a zygote to blastocyst, embryo and fetus.

Language
English
Resource Type
Publisher
Khan Academy
Publication Date
Creator/Author
Sal Khan
Comparing mitosis and meiosis
Description

Comparison of the processes of mitosis and meiosis. Mitosis produces two diploid (2n) somatic cells that are genetically identical to each other and the original parent cell, whereas meiosis produces four haploid (n) gametes that are genetically unique from each other and the original parent (germ) cell. Mitosis involves one cell division, whereas meiosis involves two cell divisions.

Language
English
Resource Type
Publisher
Khan Academy
Publication Date
Creator/Author
Sal Khan
Phases of meiosis II
Description

Meiosis is a process that creates sex cells (gametes) with half the number of chromosomes of the parent cell. Meiosis has two stages: meiosis I and meiosis II. In meiosis I, homologous chromosomes pair up and exchange genetic material (crossing over). In meiosis II, sister chromatids separate, creating four haploid cells.

Language
English
Resource Type
Publisher
Khan Academy
Publication Date
Creator/Author
Sal Khan
Chromosomal crossover in meiosis I
Description

Meiosis is a process where germ cells divide to produce gametes, such as sperm and egg cells. In prophase I of meiosis, chromosomes condense and homologous recombination takes place, leading to genetic variation through chromosomal crossover. This forms a tetrad, which is made up of four chromatids (two sister chromatids per chromosome).

Language
English
Resource Type
Publisher
Khan Academy
Publication Date
Creator/Author
Sal Khan
Comparing animal and plant cells
Description

Plant cells have a cell wall in addition to a cell membrane, whereas animal cells have only a cell membrane. Plants use cell walls to provide structure to the plant. Plant cells contain organelles called chloroplasts, while animal cells do not. Chloroplasts allow plants to make the food they need to live using photosynthesis.

Language
English
Resource Type
Publisher
Khan Academy
Publication Date
Creator/Author
Khan Academy
Cells and organisms
Description

All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular).

Language
English
Resource Type
Publisher
Khan Academy
Publication Date
Creator/Author
Khan Academy