B6 - DNA and inheritance Flashcards
what type of molecule is dna *
a polymer
what do genes do
code for a particular sequence of amino acids in order to make a specific protein
genome
the complete set of dna for an organism
3 reasons we study the human genome
- to search for genes linked with different types of diseases
- to understand inherited disorders and their treatment
- to trace human migration patterns from the past
mutation
a change in the dna sequence which can often result in changes to amino acids
what is dna profiling
the process through which a specific dna pattern is obtained from aw person or sample of bodily tissue
uses for dna profiling
- identifying disaster victims
- identifying the probable origins of bodily fluid samples associated with a crime scene
what are nucleitides
repeating monomers that make up dna
4 bases in dna
- adenine A
- thymine T
- cytosine C
- guanine G
3 parts of a nucleotide
- phosphate
- pentose sugar
- nitrogenous base
draw a nucleotide
see draw*
what is a triple codon
a sequence of 3 bases - these code for a particular amino acid
what shape is dna
double helix
why can dna be described as a double helix shape
made from two strands which twist around each
other
what is a polymer
A polymer is a large molecule made from many smaller molecules called monomers.
what is a gene
A gene is a small section on a chromosome. Each gene codes for a particular sequence of amino acids, to make a specific protein.
how are chromosomes usually found and how many are there
In human body cells the chromosomes are normally found in
pairs. Each cell has 23 pairs of chromosomes.
human genome project
The Human Genome Project (HGP) was an international scientific research project set up to map all the genetic information in a human being. was completed in 2003
what does adenine always pair with
thymine
what does thymine always pair with
adenine
what does cytosine always pair with
guanine
what does guanine always pair with
cytosine
what is it called each base only pairs with one other
complimentary pairing
4 examples of uses for proteins in the body
- hormones
- enzymes
- antibodies
- structural components i.e collagen
how many different amino acids are in the body
20
what does the sequence of a triple codon determine
A sequence of three bases is the code for a particular amino acid.
The order of the bases controls the order in which amino acids are
assembled to produce an individual protein.
draw a diagram of a dna strand
see draw*
7 steps of how dna becomes protein
- Part of the DNA unravels.
- Enzymes make a copy of the DNA strand. This is
called mRNA. - mRNA moves out of the nucleus into the cytoplasm.
- The mRNA travels to the ribosome in the cytoplasm.
- Ribosomes translate each set of 3 bases into amino acids according to the
mRNA template. - Amino acids are found in the cytoplasm. The correct amino acid for each set of
3 bases is brought to the ribosome by a carrier molecule. - A long chain of amino acids form. Their specific order forms a specific protein
3 steps for how gene code gets to the ribosome
- Part of the DNA unravels.
- Enzymes make a copy of the DNA strand. This is
called mRNA. - mRNA moves out of the nucleus into the cytoplasm.
4 steps for protein synthesis
1/. The mRNA travels to the ribosome in the cytoplasm.
2/ Ribosomes translate each set of 3 bases into amino acids according to the mRNA template.
3/ Amino acids are found in the cytoplasm. The correct amino acid for each set of 3 bases is brought to the ribosome by a carrier molecule.
4/ A long chain of amino acids form. Their specific order forms a specific protein
what happens once a protein chain is complete that allows it to carry out its function
When the protein chain is complete, it folds up to form a unique
shape. This unique shape allows the protein to carry out its role effectively
how frequently to mutations occur
Mutations occur continuously during cell division
why are most dna mutations harmless
Most of the time when a mutation occurs, the change to the coding of DNA is so slight it does not affect the protein being made. The proteins appearance and function are unchanged.
what could happen if a mutation altered the protein of an enzyme
The active site of an enzyme may have a changed shape and then
the enzyme will not be able to bind to the substrate. The enzyme will no longer function
what could happen if a mutation altered the protein of a structural protein
Structural proteins such as keratin or collagen may also lose their
strength if their shape was altered.
padlet bio slide 18/69
What does Meiosis lead to?
Meiosis leads to non-identical cells being formed.
What does Mitosis lead to?
Mitosis leads to identical cells being formed.
State the process involved when male and female gametes fuse together
Sexual Reproduction
sexual reproduction
when male and female gametes fuse together
Recall the male and female gametes found in animals.
Sperm and Egg Cells
Recall the male and female gametes found in plants.
Pollen and Egg Cells
What does mixing of genetic information lead to?
Variation of offspring
Which process are gametes formed?
Meiosis
Name the type of reproduction involves only one parent and no fusion of gametes.
Asexual Reproduction
State the term used to describe genetically identical offspring.
Clones
Which process are clones formed?
Mitosis
What happens to the number of chromosomes during meiosis?
They halve in number (23 Chromosomes)
What happens to the number of chromosomes during fertilisation?
They are restores to the full number (46 Chromosomes)
What is formed after cells in reproductive organs divide by meiosis?
Gametes
What happens to genetic information when gametes are formed?
Copies of the genetic information are made.
How many times does the cell divide to form 4 gametes?
The cell divides twice to form four gametes.
After meiosis are genetic information the same or different?
All gametes are genetically different from each other.
How do all cells except gametes divide?
Mitosis
What happens to cells as the embryo develops?
The cells differentiate
What type of reproduction leads to increased variation in offspring.
Sexual Reproduction.
What needs to happen for variation to give a survival advantage by natural selection.
Environment Changes.
State way humans can increase food production by natural selection.
Use Selective Breeding.
How many parents are needed in asexual reproduction?
Only one parent needed.
Why is asexual reproduction classes as time and energy efficient?
You do not need to find a mate.
sexual or asexual
Which type of reproduction is faster?
Asexual Reproduction.
Recall the type of offspring produced after asexual reproduction.
Identical Offspring.
How do malarial parasites reproduce in humans?
In humans = Asexually
How do malarial parasites reproduce in mosquitos?
In mosquitos = Sexually
How do fungi reproduce asexually?
By Spores.
How to fungi reproduce to give variation?
Sexual Reproduction = Variation
Name the plant which reproduces asexually.
Strawberry
Name the plant which reproduces by bulb division.
Daffodils.
bulb division
Some plants (eg. daffodils) reproduce via bulb division (new bulbs form from the main bulb underground and then grow into new identical offspring plants)