Genetics and Evolution Flashcards
Function of the Epidydimis
A mass of tubes in which sperm are stored
Function of the Penis
Can be firm to insert into the vagina of the female during sexual intercourse, to transfer sperm.
Function of the Prostate Gland
Adds fluid and nutrients to sperm to form semen
Function of the Scrotum
Holds testes
Function of the sperm duct
Carries sperm from testes to urethra
Function of the Seminal Vesicle
Adds fluids and nutrients to sperm to form semen
Function of the Urethra
Carries urine from the bladder to the outside of the body
Function of the Ovaries
Produce eggs, estrogen, and progesterone
Function of the Fallopian Tube
Carries egg to uterus
Function of the Uterus
Receive, retain, and nourish a fertilized ovum
Function of the Cervix
The opening to the uterus
Function of the Vagina
Female copulatory organ; excretory duct of uterus; part of birth canal
Function of the Oviduct
Carries an ovum to the uterus, also the site of fertilisation
Function of Urethra (Women)
Carries Urine from the bladder
What is a Gamete?
A mature sexual reproductive cell, as a sperm or egg, that unites with another cell to form a new organism.
What is Fertilisation?
The action or process of fertilizing an egg or a female animal or plant, involving the fusion of male and female gametes to form a zygote
What is the process of fertilisation
The sperm nucleus fuses with the ovum nucleus to form a zygote. A zygote is a single cell formed by the result of the fusion of two gametes.
Describe the development from a zygote to an embryo and then a foetus and then a baby
A Zygote is a fertilised cell that continutes to multiply as it travels through the fallopian tube – an Zygote is not attached to the uterus. (1-4 weeks gestation)
An Embryo is attached to the uterus but does not yet resemble the shape of a baby (5-9 weeks gestation)
A fetus resembles a baby in the womb (10-42 weeks gestation)
We use the term “baby” to describe the fetus once it has been born.
What are Haploid and Diploid Cells (three points for each cell)
Haploid - One set of Chromosomes, In Humans, number (n) = 23. In Humans, gametes are haploid cells.
Diploid - Two sets of chromosomes, In Humans, 2n = 46. In Humans, all body cells (other than gametes) are diploid cells.
Brief Definition of DNA (two points)
- DNA is found in the shape of a double helix. A double helix is a twisted staircase shape.
- DNA is made up of four base pairs:
G, C, T and A
What is the overall definition for DNA?
Located in the nucleus and made up of repeating base pairs, DNA is the instructions for all of our physical characteristics. DNA is the carrier of our genetic information
What are Genes?
A Gene is a section of DNA which codes for a specific characteristic. eg. Hair colour, height or eye colour
What are chromosomes?
A Chromosome is a length of DNA which is made up of many genes. Chromosomes are stored in the Nucleus of a cell. Humans have 46 chromosomes in their somatic cells
State the location of DNA/Genes in a Cell
DNA/Genes/Chromosomes are found in the Nucleus of the cell
What is a Mutation?
An accidental alteration in a genetic message. A mutation may be harmful or helpful, small or big.
What is Chromosomal Mutation and Gene Mutation
Chromosomal: An error that affects an entire chromosome.
This can causes Chromosomal disorders such as Down syndrome.
Gene: An error in a length of DNA which affects the expression of a gene.
This can cause genetic disorders such as sickle cell anaemia or cystic fibrosis
Examples of Harmful Mutations
Skin cancer, debilitating diseases, and deformed limbs
Examples of beneficial mutations
Elephants being born without tusks or Polar bears having hollow fur.
What is a Phenotype?
is the PHYSICAL characteristics of an individual. i.e –Brown hair, blue eyes etc
What is a Genotype?
is the GENES responsible for the characteristics of an individual. i.e. hair colour or eye colour
State that all cells (Except gametes)
have 2 genes/alleles for each characteristic
In our cells we have TWO sets of chromosomes. One set from our mum, the other from our dad. Each set of chromosomes have the same genes on them.
When we refer to our genes are we referring to haploid or diploid cells?
When considering why we look and act the way that we do, we are looking at both sets of our chromosomes (one set from mum, one from dad) - DIPLOID
What is a Allele?
A different form of a gene.
Eg. If the gene is hair colour – the alleles present would be Black, Brown, Blonde and Red
What is a Dominant Gene/Allele
In genetics, an allele which shows its effect when there is only one allele of a pair.
What is a Recessive Gene/Allele
In genetics, a gene that is not expressed if the dominant allele is also present.
What is Homozygous?
Homo = “The same”
A genotype is Homozygous when it is made up of TWO of the SAME alleles.
HH for handedness would be Homozygous Dominant
or tt for hitchhiker thumb would be Homozygous Recessive
What is Heterozygous?
Hetero = “different”
A genotype is Heterozygous when it is made up of TWO DIFFERENT alleles.
Hh for handedness would be Heterozygous Dominant
or Tt for hitchhiker thumb would be Heterozygous Dominant
What is Variation?
Variation is the differences between individuals.
Variation is brought about due to an individuals genes that we inherit and the environment we live in.
What are the environmental factors that affect our phenotypes?
diet, culture, geography, friends, pollution etc.
What is Discrete Variation
Discrete variation refers to differences in traits that fall into distinct categories
What is Continuous Variation
Continuous variation refers to traits that show a range of values
Examples of Discrete Variation
Blood Type and Eye Colour
Examples of Continuous Variation
Height or Skin Colour
What is Cell Division
Cells must divide so we can replace old ones, repair damaged cells, grow bigger or reproduce.
What is Mitosis Responsible For?
- Growth and Repair
- Mitosis produces Identical Diploid Cells so that they can carry out exactly the same function as the “parent cell”.
What is Meiosis Responsible For?
- Producing Sperm or Egg Cells (Reproduction)
- Meiosis creates variation between cells, making each baby unique. This is why you and your siblings differ.
What does DNA stand for?
Deoxyribonucleic Acid
What are 3 causes of mutations?
Radiation, errors during cell division & chemicals
Where does Meiosis occur in flowers?
In the anther and ovary
What is Selective Breeding?
Selective breeding aims to adapt an organism’s characteristics in a way that is desirable to the humans that breed them.
What is Fitness?
In natural selection, fitness measures success. Fitness is the measure of how well organisms survive and reproduce.
Discuss Darwin’s Idea of Evolution
Natural selection is a species ability to adapt to a changing environment.
Why is Natural Selection Important?
If we were all the same we wouldn’t be able to cope with a changing environment. Some of us are better at coping with the heat, some prefer cold weather. Some are better at fighting off diseases.
