Reproduction and Inheritance Flashcards
What is the difference between a zygote and an embryo?
The zygote is the diploid cell formed from the fusion of a sperm and egg cell, it become an embryo after it starts to divide.
What is the difference between asexual reproduction and sexual reproduction
-Asexual reproduction involves mitosis to produce genetically identical copies.
-Sexual reproduction involves the combination of sperm and egg cells to create a zygote
What is the difference between a zygote and an embryo?
The zygote is the diploid cell formed from the fusion of a sperm and egg cell, it becomes and embryo after it begins to divide
Give one advantage and one disadvantage of sexual reproduction.
Advantage-It introduces variation
Disadvantage-It is slower and produces a limited amount of offspring
Give one advantage and one disadvantage of asexual reproduction?
Advantage-It produces lots of offspring quickly
Disadvantage-It does not introduce variation
3 features of insect pollinated plants
-Bright colours
-Sweet nectar
-Sticky pollen
3 features of wind pollinated flowers
-Bland colours
-Stigma exposed to the air and feathery
-Light pollen
Describe the process of fertilisation in plants
-Pollen lands on the stigma
-Pollen tube begins to grow from the pollen grain into the ovary
-Pollen grains travel down the pollen tube and fertilizes the egg
-Fruit and seeds from the egg
How can seeds grow before they can photosynthesise?
They use stores of starch
Give one natural example of plant cloning
Plant runners from strawberries
Give one artificial example of plant cloning
Tissue cuttings placed in a growth medium
Where are eggs produced
Ovaries
How are egg cells adapted to their function?
-Large cells
-Large cytoplasm for the lots of divisions they undego
-They have haploid nucleus
-Jelly coat to protect the egg
How are sperm cells adapted to their function?
-Acrosome contains enzymes so the sperm can penetrate the egg
-Haploid nucleus
-Tail so that it can swim
-Lots of mitochondria
Purpose of amniotic fluid.
Protect the developing foetus
Purpose of the placenta
To allow nutrients and oxygen to pass from the mother to the fetus during development. The bloods may never come in contact though.
What role does estrogen play during puberty?
-Increase breast size
-Triggers the development of the uterus
-It causes eggs to mature during the menstrual cycle.
What role does testosterone play during puberty?
-Triggers growth and development of the penis and testes.
-Causes voice to deepen
-Triggers the growth of pubic hair
-Increases the muscle mass.
What is the genome?
All of the genes present in an organism
What is a gamete
Sex cells
What is a chromosome?
Tightly package DNA.
How many chromosomes do human body cells have?
46 chromosomes (23 pairs)
How many chromosomes do gametes have?
23 chromosomes
Where are chromosomes located?
In the nucleus
What is a gene?
Section of DNA that codes for protein
Describe the structure of DNA
-Polymer made from nucleotide monomers
-2 strands in double-helix
4 bases in DNA
A-T
C-G
2 differences between DNA and RNA
-RNA is single stranded
-RNA has Urecil instead of Thymine
Describe transcription
-DNA unzipped by RNA polymerase
-Complementary mRNA nucleotides bind and are joined together
-mRNA detaches and leaves the nucleus.
Define Codon
A group of 3 bases on the mRNA molecule that code for a single amino acid.
Define anticodon
3 bases on the tRNA molecule that match the codon on the mRNA molecule.
Describe translation
-mRNA travels to ribosome
-tRNA molecules with an anticodon that matches the codon on the mRNA molecule carry amino acids to the ribosome.
-The amino acids are joined together into a long chain
How does the sequence of bases affect the protein made in protein synthesis
DNA is a triplet code where 3 bases code for one amino acid and the order of the amino acids determines the protein produced.
Define allele
Different versions of the same gene
Define dominant allele
A version of a gene where only one copy is needed for it to be expressed
Define recessive allele
A version of a gene where two copies are needed for it to be expressed
Define homozygous
When an organism has two copies of the same allele.
Define heterozygous
When an organism has two different versions of the same gene
Define genotype
Genes present for a trait
Define phenotype
Visible characteristic
What does a punnett square do?
Allows you to see what is the possibility of inheriting a trait.
What do family pedigrees show?
The inheritance of an allele over generations.
What is codominance?
When two alleles affect the phenotype
What is monohybrid inheritance
The inheritace of one allele
3 processes that require mitosis
-Growth
-Repair
-Asexual reproduction
How many cells does mitosis produce
One parent cell produces two daughter cells.
How many cells does meiosis produce?
One parent cell produces 4 daughter cells.
Difference between mitosis and meiosis
Mitosis produces diploid cells wherease meiosis produces haploid cells.
What are the two types of variation?
Genetic and environmental.
What is randm fertilisation?
-Random chance of a specific sperm combining with a specific egg
-This increases variation as any female can mate with any male and any one of the millions of sperm could fertilise the egg
What is a mutation?
A random change in the genetic material of an organism.
How do mutations affect the phenotype
-Mutations alter the genetic material
-This can cause it to code for a different sequence of amino acids
-A different sequence of amino acids means that the protein will be different.
Describe the process of natural selection
-Populations are naturally varied due to random genetic mutations.
-Some of these mutations provide a selective advantage
-These organisms survive and reproduce, passing on the successful genes.
Define evolution
Change in the genetic makeup of a population over time due to natural selection.
What are the 2 types of variation
Genetic variation and environmental variation
3 environmental factors that increase the chance of mutations
-Exposure to UV radiation
-Exposure to X-Rays
-Certain chemicals, particularly those found in cigarette smoke
Define evolution
Evolution is a change in the genetic makeup of a population over time due to natural selection
Describe how antibiotic resistance arises
-A random genetic mutation causes bacterium to become resistance to the antibiotic
-When the antibiotic is used, all the bacteria that do not have that mutation are killed
-The population containing just the resistant bacteria then begins to grow.
What are the risks of antibiotic resistance?
Bacteria that causes infection that are resistant to antibiotics are hard to treat and can pose a serious threat to our health
