Biology genetics notes

At fertilisation any male gamete can fertilise any female gamete at random.

Biology genetics notes

Off springs sexually mature individual Transmission of characters from the parents to off springs is by gametes. The male organism if animal contributes sperms and in plants pollen grains The Female animal contributes ova and in plants it will contribute ovules.

Animals have to mate to bring the two gametes together. When the female and male gametes fuse, fertilization is said to have occurred. Fertilization is the fusion of the male and female nuclei to form a zygote.

Biology genetics notes

In animals the zygote is formed Biology genetics notes the fallopian tube and it begins to undergo growth growth is an irreversible increase in the size of an organism.

Growth occurs by cell division. The type of cell division which leads to growth is mitosis. The zygote also undergoes development.

IB Biology Notes - Membranes

Development is the change in shape and form. Growth and development eventually lead to a sexually mature organism. Sexual maturity in flowering plants is evidenced by the on set of flowering.

In female animals its evidenced by ovulation and in male animals by sperm development. In body cells chromosomes are found in pairs Half from the female parent and half from the male parent. Chromosomes These are threadlike structures found in the nucleus of the cell and they contain the genetic material responsible for inheritance.

They form the physical basis for inheritance since their structure can be observed under a high power microscope.

Simplified structure Each chromosome is made up of two longitudinal strands called the chromatids. Each chromatid has a double helical DNA molecule. The two chromatids are held together by a structure called the centromere.

During cell division, the spindle fibres are attached to the centromeres. The chromosomes are present in pairs. The pairs are called the homologous pairs they must be similar in structure and also have the same chemical composition.

A species will always have the same number of chromosomes. This is called the chromosome number and it will always be an even number. This number is called the diploid number.

During gamete formation, the homologous chromosomes separate and the gametes will have only half the number of chromosomes. This number is called the haploid number.Genetics is the study of how genes bring about characteristics, or traits, in living things and how those characteristics are inherited.

Genes are specific sequ Introduction to . IB Biology notes on Membranes. Membranes Draw and label a diagram to show the structure of membranes..

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Figure - Annotated drawing of a cell membrane. Explain how the hydrophobic and hydrophilic properties of phospholipids help to maintain the structure of cell membranes..

Cell Biology

Phospholipid molecules make up the cell membrane and are hydrophilic (attracted to water) as well as.

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This section provides the schedule of lecture topics and lecturers, student notes, and the lecture slides used for the course.

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