Mendel, Heredity, and genes Flashcards
What is DNA?
DNA stands for Deoxyribonucleic acid.
It is an essential molecule of life
It gives instructions to cells
It is a long thin molecule made of nucleotides. There are 4 different types of nucleotides:
Adenine
Thymine
Cytosine
Guanine
What are chromosomes?
Chromosomes are tiny structures inside cells made from DNA and protein.
The information in chromosomes tells cells how to function and replicate
Chromosomes describe the color of your eyes, height, and whether you’re a boy or a girl.
Where are chromosomes located?
Chromosomes are found in the nucleus of every cell. Different forms of life have different numbers of chromosomes in each cell. Humans have 23 pairs of chromosomes to total of 46 chromosomes in each cell.
What do chromosomes look like?
When the cell is not dividing (interphase) the chromosome is in its chromatin form. In this form, it is a long, very thin, strand. When the cell starts to divide the strand replicates itself and winds up into shorter tubes. Before the split, the two tubes are pinched together at a point called the centromere. Shorter arms are called p arms and longer arms are called q arms.
Describe the process of cell division
- Interphase
The cell grows and develops. DNA doubles and the nucleolus is in the nucleus - Prophase
Chromosomes are now visible. The nuclear membrane breaks down, and the spindle fibers (Threads of protein) are seen - Metaphase
The chromosomes line up. The spindle fibers attach to the center of each chromosome - Anaphase
The chromosomes split. Each half is pulled to the opposite side of each cell - Telophase
The chromosomes cluster at separate ends of cells. The nuclear membrane begins to form. Cells begin to separate - Cytokinesis
The cytoplasm divides. The same number of chromosomes are in both of the cells. Two daughter cells are formed.
Describe the steps of mitosis.
Prophase
Metaphase
Anaphase
Telophase
Cells in the body
Our body has around 210 different cells. Each cell has a different function. Cells get their instructions from DNA
What is DNA code?
DNA is held by the different letters of the nucleotides. As the cell reads the instructions on the DNA the different letters represent different instructions. Every 3 letters make a word called a codon.
What are genes?
Within each DNA there is a set of instructions called genes. A gene tells a cell how to make a specific protein. Proteins are used by the cell to perform certain functions.
What is the shape of a DNA molecule?
The shape is called a double helix. On the outside is the sugar-phosphate backbone. Between the backbone, the nucleotides are represented. Only certain sets of nucleotides can fit together.
What is an allele?
A specific pattern in the gene is called an allele. It is the different forms of the same gene. It can determine hair color etc.
What pair of the X/Y do girls and boys have?
Girls - XX
Boys - XY
What is gene variation?
It is the mutation in the sequence of the nucleotides that make up the gene and hence changes the instructions from the DNA. This happen regularly through mistakes in replicating DNA. Mutations can delete or change nucleotides, they can even change pieces of a chromosome
What is gene flow?
The mixing of genetic information among interbreeding members of a population or species is called gene flow. It maintains consistency within populations.
What is a restriction in gene flow?
When a singular population becomes two separate populations because of a physical barrier.
What is a restriction in gene flow?
When a singular population becomes two separate populations because of a physical barrier.
What is speciation?
It is the splitting of a single species onto twp descendent species.
What is meiosis?
Meiosis is cell division that produces sex cells with only half the number of chromosomes. During meiosis the cell undergoes two divisions to produce four sex cells, each which half the number of chromosomes of the parent cell.
