Biology genetics

Nucleotide

one building block of DNA. It contains:

1. A sugar molecule (deoxyribose in DNA).

2. A phosphate group.

3. A nitrogenous base.

Genetics

The study of how characteristics pass from parents to offspring.

DNA

The molecule that stores genetic instructions.

DNA stand for?

Deoxyribonucleic acid

Double Helix

The twisted ladder shape of DNA

Nitrogenous base

A part of a nucleotide that forms the rungs of DNA.

Hydrogen bonds

Holds complementary DNA bases together.

Deoxyribose

The sugar found in DNA

Phosphate group

Joins with sugar to form the DNA backbone.

Base Pairings

A=T, C=G

Chargaff's rule

The amount of A equals T, and the amount of C equals G in DNA.

Evolution

Change in inherited characteristics of populations over generations.

Scientific model

A simplified representation of an object, system or process.

Gene

A section of DNA containing instructions for making a specific protein.

Chromosome

A tightly packaged structure of DNA and proteins that carries genes.

Chromatin

DNA wrapped around proteins in long, thread-like strands.

Histones

Proteins that DNA wraps around.

Genome

All the genetic information in an organism.

Homologous chromosomes

A pair carrying the same genes in the same positions, one from each parent.

Karyotype

A picture of chromosomes arranged in pairs.

Diploid (2n)

A cell containing two sets of chromosomes.

Haploid (n)

A cell containing one set of chromosomes.

Autosomes

Chromosomes other than the sex chromosomes.

Sex chromosomes

Chromosomes involved in biological sex determination.

Somatic cell

A body cell.

Gamete

A reproductive sex cell, such as sperm or egg.

Centromere

The region joining sister chromatids together.

Sister chromatids

Two identical copies of a chromosome after DNA replication.

Reproduction

The process of producing offspring.

Asexual reproduction

One parent produces offspring without fertilisation.

Sexual reproduction

Reproduction involving the fusion of gametes.

Clone

An organism genetically identical to another.

Fertilisation

The fusion of sperm and egg, or other compatible gametes.

Zygote

The cell formed by fertilisation.

Genetic variation

Differences in genetic information between individuals.

Asexual Reproduction(Binary Fission)

One cell divides into two. (bacteria)

Asexual Reproduction(budding)

A small outgrowth develops into a new organism. (yeast)

Asexual Reproduction(fragmentation)

Pieces of an organism grow into new organisms. (planarians)

Asexual Reproduction(Vegetative propagation)

A new plant grows from a stem, root or leaf.(strawberry)

Asexual Reproduction(parthenogenesis)

An unfertilised egg develops into an organism.(aphids)

Asexual Reproduction Purpose & Rules

Usually faster, requires less energy and produces little genetic variation.

Sexual Reproduction Rules & Purposes

Usually slower, requires more energy and creates greater genetic variation.

Purpose of reproduction

To produce offspring and continue the species.

Purpose of genetic variation

It increases the chance that some individuals in a population can survive environmental changes.

Offspring

A new organism produced by a parent through reproduction.

Cell division

The process of producing new cells.

Cell cycle

The stages a cell goes through as it grows, copies DNA and divides.

Interphase

The cell grows, functions normally and copies its DNA.

Mitosis

Nuclear division producing two identical nuclei.

Cytokinesis

Division of the cytoplasm to form two daughter cells.

Daughter cells

The new cells produced by cell division.

Spindle fibres

Fibres that move chromosomes or chromatids during division.

PMAT

The four stages of mitosis: Prophase, Metaphase, Anaphase, Telophase.

Prophase

Chromosomes become visible, and spindle fibres form.

Metaphase

Chromosomes line up in the middle of the cell.

Anaphase

Sister chromatids separate and move to opposite ends.

Telophase

Two new nuclei form.

Meiosis

Cell division that produces four genetically different haploid cells.

Gonads

Reproductive organs that produce sex cells.

Testes

Male reproductive organs that produce sperm.

Ovaries

Female reproductive organs that produce eggs.

Meiosis 1

Homologous chromosomes separate.

Meiosis 2

Sister chromatids separate

Mitosis Purpose

Growth, repair and replacement of cells.

Purpose of interphase

o grow and copy DNA so each new cell can receive a complete set of genetic information.

Purpose of meiosis

To make gametes with half the usual chromosome number and create genetic variation.

Purpose of crossing over

They create different combinations of genetic information in gametes.

Science model strengths

A feature that makes a model useful or accurate.

Science Model limitations

Something a model cannot show or represents inaccurately.

Scale

The relationship between the size in a model and the real object.

Evidence

Information or observations that support a scientific explanation.

Fertilisation Rule

23 chromosomes from the sperm and 23 chromosomes from the egg = 46 in the human zygote