Inheritance Flashcards
Who worked out the Structure of DNA?
James Watson and Francis Crick.
When was the Structure of DNA worked out?
1953.
What does DNA stand for?
Deoxyribonucleic Acid
What shape is DNA?
DNA is made up of two long strands, arranged in a double helix structure.
What does DNA carry?
It carries the genetic code.
What is the genetic code?
Genetic code carries all the instructions that a living organism needs to grow, reproduce and function.
How is DNA passed on?
DNA is passed on from parents to offspring during fertilization.
What are the basic units of DNA?
Nucleotides.
What does each nucleotide consist of?
Deoxyribose Sugar,
Phosphate Group,
Nitrogen Base.
What are the types of Nitrogen Bases?
A - Adenine
T - Thymine
G - Guanine
C - Cytosine
What Nitrogen bases go together?
AT
GC
What stays the same in Nucleotides and what differs?
All Nucleotides contain the same phosphate and deoxyribose sugar.
However, they have a different base.
What forms the backbone of the nucleotide?
Sugar-Phosphate Backbone.
What joins base pairs together?
Hydrogen bonds.
What’s a DNA molecule?
Many nucleotides attached together form a chain. Two of these chains form a DNA molecule.
When are chromosomes formed?
During cell division, long strands of DNA condense into structures called chromosomes.
How many chromosomes are in each cell?
23 pairs (46 chromosomes), half from each parent.
What cells contain chromosomes?
All human body cells contain chromosomes except two types.
What types of cells don’t contain all chromosomes?
Gametes (sex cells) contain only 23 chromosomes. Red Blood Cells (RBCs) don’t have chromosomes either.
What are chromosomes?
Chromosomes are thread-like structures of DNA, carrying genetic information in the form of genes. They are located in the nucleus of the cell. Human body cells (except gametes and RBCS) contain 23 pairs of chromosomes (46 in total).=.
Why do RBCs not have chromosomes?
Because they don’t have a nucleus.
Where in the cell are chromosomes located?
In the nucleus.
Chromosomes are matched based on their…
size and shape
What are matching pairs of chromosomes called?
Homologous chromosomes.
Homologous roots:
homo=same
logos= ratio, proportion
Why do human gametes (eggs and sperm) have 23 chromosomes?
When an egg cell is fertilised by a sperm, it becomes a cell with 46 chromosomes (23 pairs). This is why children resemble both of their parents - half of their chromosomes come from their mother and half from their father.
How many types of Chromosomes are there?
23 types.
What is the 23rd pair of chromosomes called, and why is it significant?
The 23rd pair of chromosomes are called sex chromosomes, and it’s significant because these chromosomes decide the gender of the person.
What is the 23rd chromosome for girls?
XX
What is the 23rd chromosome for boys?
XY
What is a gene?
A specific sequence of DNA which contains information to produce a particular protein.
What is the function of a gene?
Contains information to produce a particular protein in the body.
Example of a gene and the protein it produces?
Gene for keratin production has instructions to produce keratin protein in the hair.
Genes usually occur in…
pairs, one from each parent (means you have two copies of each gene).
What is a gene?
A specific sequence of DNA which contains information to produce a specific protein. Genes usually occur in pairs, one from each parent.
What’s a homologous chromosome?
Matching pairs of chromosomes are called chromosomes. One for each parent.
What are genomes?
A complete set of gene or genetic material present in a cell or organism.
What are alleles?
Alternative forms of a gene.
What is homozygous?
If the 2 alleles of a gene are the same, we call the individual homozygous.
Examples of homozygous alleles?
AA and aa.
What is heterozygous?
If the 2 alleles of a gene are different, we describe the individual as being heterozygous.
Example of heterozygous?
Aa.
What’s a genotype?
The genetic makeup of an organism.
What’s a phenotype?
A physical expression of a character.
Who is Gregor Mendel?
Gregor Mendel is known as the father of genetics. He carried out experiments crossing plants with different characteristics. He determined that:
Characteristics are determined by factors within the organism (genes).
The factors (genes) can be present in two different forms (alleles).
What’s co-dependance?
The pattern of inheritance when both alleles are expressed in the genotype is called co-dominance.
Example of codomincance?
Flower colour in snap dragons.
Red + White
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