3b - Inheritance Flashcards
Define inheritance:
transmission of genetic information from generation to generation
What is the genome?
the entire genetic material of an organism
What is a gene?
a short length of DNA found on a chromosome that codes for a specific protein
What is a chromosome?
made up of proteins and DNA organised into genes and are located in the nucleus of cells
How many different chromosomes does each cell in a human have?
23 chromosomes
Why are there 46 chromosomes in total?
because normal cells have 1 copy of each chromosome
How many chromosomes do gametes have?
only 1, 23 in total
What are alleles?
variations of the same gene
What is the phenotype?
the actual characteristic expressed by the person’s genes (physical)
What is the genotype?
the combination of alleles that a person has that codes for their specific phenotype (genetic)
What is the dominant allele?
gene that is inherited from only 1 parent, shown in capital letter
What is the recessive allele?
gene that is inherited from both parents, shown in lower case letter
What does homozygous mean?
when the two alleles of a gene are the same (bb)
What does heterozygous mean?
when the two alleles of a gene are different (Bb)
What does polygenic mean?
characteristics that are controlled by more than one gene
What is monohybrid inheritance?
inheritance of characteristics controlled by a single gene
What is the male genotype of a human?
XY
What is the female genotyoe of a human?
XX
What are diploid cells?
all human cells that have 46 chromosomes
What is mitosis?
- a diploid cell makes a copy of each chromosome
- chromosomes line up in the center where they are pulled apart
- the nucleus divides to produce 2 identical daughter cells
Why is mitosis important?
- all cells in the body are produced by mitosis
- important for growth and replacing cells
What are haploid cells?
- cells that have 23 chromosomes (gamete cells)
What is meiosis?
- diploid cell makes a copy of each chromosome
- maternal and paternal chromosomes mix together
- first division: diploid cell divides to produce 2 new diploid cells with mixed chromosomes
- second division: the 2 new diploid cells divide to produce 4 haploid cells that are genetically different to each other
Why is meiosis important?
- produces gametes
- increases genetic variation of offspring
How many cells does mitosis produce?
2 cells
How many cells does meiosis produce?
4 cells
What type of cells does mitosis work with?
diploid cells (46 chromosomes)
What type of cells does meiosis work with?
haploid cells (23 chromosomes)
Mitosis produces genetically _________ cells
identical
Meiosis produces genetically _________ cells
different
What are some examples of genetic variations?
- blood type
- eye colour
- ability to roll tongue
What are some examples of environmental variations?
- a plant in the shade will grow taller to reach more sunlight
What are mutations?
mutations are random changes that occur in a gene or a chromosome and it can be inherited
What is evolution?
the change in the frequency of a phenotype in a population over many generations
What is an antibiotic?
a chemical that can kill or inhibit the growth and reproduction of bacteria
What are the problems of overusing antibiotics?
this can lead to mutations and diseases being harder to control
