DNA and Redproduction Flashcards
Sexual reproduction
Fusion of Male and female gametes, non identical offspring, meiosis
Advantages of sexual reproduction
Genetically different, Variation of offspring
Disadvantages of sexual reproduction
Hard to find a mate, growing offspring takes energy, slower
Asexual reproduction
One parent, identical offspring, mitosis, no gametes
Advantages of asexual reproduction
Less effort, dont need to find a mate, increase population, no time wasted
Disadvantages of asexual reproduction
Genetically identical so could be wiped out by pathogens
Sex cells in plants and animals
Pollen and egg, Sperm and egg
Meiosis
Starts with parent cell
Chromosomes copy themselves
Similar chromosomes pair up (size)
Sections of DNA swap - differentiate
First cell division separates pairs
Second cell division forms 4 genetically different gametes.
What do the gametes do during fertilisation?
Join back up to restore original number of chromosomes.
Mitosis
Inter-phase - Cell grows, replicates its DNA and prepares for division.
Pro-phase - the chromosomes condense into an X-shaped structure
Meta-phase - Nuclear membrane breaks down and chromosomes line up in the center of the cell.
Ana-phase - the sister chromatids separate from each other and are pulled towards opposite ends of the cell
Telo-phase - separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells
Cytokinesis - divides the cytoplasm of a parental cell into two daughter cells
Gene
Short section of DNA that codes for a specific protein
Genome
Entire genetic material of an organism
Why is it important to understand the human genome
search for genes linked to different types of disease. understand inherited disorders and their treatment. trace human migration patterns from the past
Four bases and complementary pairing?
A - T
T - A
C - G
G - C
How do bases code for proteins?
3 bases form a codon which code for different amino acids which form a chain and fold into correct proteins
DNA polymer
contains multiple repeating units
How are proteins synthesized on ribosomes?
translating the genetic code transcribed in mRNA into an amino acid sequence
What do proteins turn into?
Enzymes, hormones or structures
Mutations
Occur continuously and most don’t alter protein
What does non-coding DNA do?
Can switch genes on and off, so variations in this area of DNA may effect how genes are expressed
Genotype
gene that an organism carries for a trait
Phenotype
gene that an organism carries for a physical manifestation that you can observe
Allele
Different versions of the same gene
Dominant
When present, this allele always appears in phenotype
Recessive
When present, allele only appears in homozygous
Heterozygous
Carrying 2 different alleles of the same gene (xY)
Homozygous
Carrying 2 similar alleles of same gene (xx)
Punnet squares
Must fill out grid, label each side as hetero/homozygous, write percentage chance
Inherited disorder caused by dominant allele?
Polydactyly - Extra finger or toe
Inherited disorder caused by recessive allele?
Cystic fibrosis - Lung issues, phlegm
How many chromosomes are usually in a human?
46 (23 pairs)
Which chromosomes determine sex?
46 chromosome (xx/xY)
DNA
is a polymer made up of 2 long strands of small units that repeats throughout the structure called nucleotides
Haploid cell
4 genetically different gametes produced by sexual reproduction
