Science - biology Flashcards
(26 cards)
I can describe the structure of DNA.
DNA is a double stranded, double helix molecule.
I know where DNA is found in the cell.
DNA is found in the nucleus of the cell. It is
arranged as chromosomes.
I can define the term ‘gene’.
A gene is a section of a chromosome that code for
a particular characteristic e.g. hair colour.
I can state what is meant by an allele.
An allele is an alternate form of a gene. E.g. if
gene is eye colour, the allele may be blue eyes,
brown eyes, green eyes.
I can distinguish between homozygous and
heterozygous alleles.
Homozygous alleles are inherited alleles that are
the same. e.g. TT
Heterozygous alleles are inherited alleles that are
different e.g. Tt
I can state what is meant by selective breeding.
Selective breeding is when humans choose
parents to breed together.
These parents have particular desirable
characteristics to and are likely to produce
offspring with the same desirable characteristics.
I can state what is meant by genetic engineering.
Genetic engineering is a process which involves:
Changing the genes of an organism
by introducing a gene from another organism to
give a desired characteristic.
What does ‘GMO’ stand for.
GMO = Genetically modified organism.
I can describe what is meant by a clone.
Cloning is making a genetically identical copy of
an individual. It can happen naturally or
artificially.
Where are genes found?
Genes are found in chromosomes, which are located in the nucleus of a cell
What do genes do?
Genes are instructions in DNA that determine an organism’s traits and control its biological functions.
Which part of the cell do you find chromosomes?
Chromosomes are found in the nucleus of the cell.
How many chromosomes do humans have in:
A) body cells
B) sex cells
A) Humans have 46 chromosomes in their body cells, arranged in 23 pairs.
B) Sex cells have 23 chromosomes, half the number found in body cells.
How can u tell the sex of an organism, when looking at chromosomes?
by looking at the sex chromosomes: females typically have two X chromosomes (XX), and males have one X and one Y chromosome (XY).
Show the probability of having a boy or a a girl using a punnet square
X X
X XX XX
Y XY XY
XX=Girl XY=Boy
So, there’s a 50% chance of having a boy and a 50% chance of having a girl.
What is the definition of allele?
An allele is a different version of a gene that can exist at a specific location (locus) on a chromosome. Alleles can determine specific traits, such as eye color, and can be dominant or recessive.
What is the definition of dominant allele?
A dominant allele is one that masks the effect of a recessive allele and determines the organism’s trait when present.
What is the definition of recessive allele?
A recessive allele only expresses its trait when two copies are present, one from each parent, and is masked by a dominant allele.
What is the definition of Phenotype?
The phenotype is the physical appearance or traits of an organism.
What is the definition of Genotype?
The genotype is the set of genes an organism inherits from its parents.
What is the definition of Homozygous?
Homozygous means having two of the same allele for a gene.
What is the definition of Heterozygous?
Heterozygous means having two different alleles for a gene.
DNA is short for ____________ _____ acid.
It is a long chain _______ that is made up of a combination of _ DNA bases.
DNA has a special structure called a _______ _______.
- deoxyribonucleic acid
- molecule
- 4
- double helix
A gene is a short section of a __________. Each gene _____ for a different __________. Genes work in _____. There are different versions of each gene, one is often ________ over the others.
- Chromosome
- codes
- characteristic
- pairs
- dominant
