Reproduction Flashcards
How many parents in sexual reproduction?
Two
How many parents in asexual reproduction?
1
How does cell division take place in sexual reproduction?
Meiosis
How does cell division take place in asexual reproduction?
Mitosis
How does the formulation take place in sexual reproduction?
Fusion of male and female gametes - sperm and egg or pollen and ovule
How does the formulation work in asexual reproduction?
No fusion of gametes
What are the offspring like from sexual reproduction?
Produces non-identical offspring that are genetically different to parents
What are the offspring like from asexual reproduction?
Produces clones/ offspring genetically identical to parents
Is there genetic variation from sexual reproduction?
Wide variation between offspring and species
Is there genetic variation from asexual reproduction?
No mixing of genetic information
What are advantages and disadvantages of asexual reproduction?
Only one parent needed
Time and energy efficient as no mate
Faster
Many identical offspring can be produced in favorable conditions
Successful traits passed on
Reduced genetic variation
Harmful mutations passed on
What are advantages and disadvantages of sexual reproduction?
Produces variation
Results in survival advantages through natural selection
Time consuming
Slower
How do malarial parasites reproduce?
Asexually in humans and sexually in mosquitos
How do fungi reproduce?
Asexually by spores but also sometimes sexually
How do plants reproduce?
Through seeds sexually but asexually by bulb division in daffodils and runners in strawberry plants
What is meiosis?
Cell division that makes gametes in the reproductive organs
DNA is replicated in the parent cell
Four genetically different daughter cells
Gamete
Specialised sex cell formed by meiosis
Chromosome
Long molecule found in the nucleus of cells made from DNA
Gene
Part of a chromosome that codes for a protein, some characteristics controlled by a single gene, but most controlled by interaction of different genes
Allele
Different forms of the same gene
Dominant
Allele that only needs one copy to be expressed
Recessive
Allele that needs two copies present to be expressed
Homozygous
When an individual carries two copies of the same allele for a trait
Heterozygous
When an individual carries two different alleles for a trait
Genotype
Combination of alleles an individual has
Phenotype
Physical expression of the genotype
What is DNA?
Genetic material in the nucleus is composed of DNA
DNA is made up of two strands forming a double helix
DNA is contained in chromosomes
What is a gene?
A small section of DNA on a chromosome that codes for a specific sequence of amino acids to produce a specific protein
What is a genome?
The entire genetic material of an organism
What has studying the genome allowed scientists to do?
Search for genes linked to different diseases
Understand and treat inherited disorders
Trace human migration patterns from the past
What is the structure of DNA?
DNA is a polymer made from four different nucleotides
Made from a phosphate, a sugar and one of four organic bases (A, C, G, T)
A sequence of three bases codes for a particular amino acid
The order of bases determines the order in which amino acids are assembled to produce a protein
AT/ CG
What is protein synthesis?
Proteins are synthesised on the ribosomes using a template of DNA
Carrier molecules bring amino acids to add the protein chain in the correct order
When the protein is complete it fold up to form a specific shape and this shape allows proteins to do specific jobs as enzymes and hormones or forming structures
Non-coding parts of DNA can control the expression of genes by switching them on and off
What are mutations?
Mutations occur continuously and change the base code of DNA. In coding DNA they may alter the activity of a protein
Most don’t alter appearance or function of the protein
A gene could synthesise a different protein
What is polydactyly?
Caused by dominant allele, extra fingers or toes
What is cystic fibrosis?
A disorder of cell membranes, caused by a recessive allele
Hoe can suffering be alleviated from disorders?
Embryo screening
Gene therapy
What is a genetic cross or Punnett Square?
Considering the offspring that might result from two known parents
What is sex determination?
Female XX
Male XY
One of the 23 pairs of chromosomes code for sex
