Genetics Flashcards
why do animals need to reproduce
essential to the survival of different species
what are the two different types of reproduction
asexual and sexual (lol)
what does sexual reproduction entail
fertilisation (internal/external)
what is asexual reproduction
asexual reproduction only requires one parent and no fertilisation. It occurs when a single cell splits into two or when a multicellular organism produces offspring that are clones. The offspring have the same genes and therefore the same characteristics.
what is sexual reproduction
sexual reproduction requires two parents and fertilisation(when two gametes, one from the male and one from the female fuse together) The new cell contains a full set of genes from both parents and therefore a mixture of characteristics from both.
what is external fertilisation
external fertilisation is when the sperm and egg fuse outside other the females body (trout and frogs)
what is internal fertilisation
internal fertilisation is when the sperm and egg fuse inside the females body (necessary as there is no immediate water in land animals immediate environment to carry sperm to egg - semen)
why does internal fertilisation have a greater success rate than external fertilisation
1) Higher chance of fertilisation occurring
2) Fertilised eggs are protected during development
3) Young are provided with food and protection from parents
what are the parts of a human male reproduction system
testis, glands, sperm duct, urethra and penoos
what are the functions of the structures of the male reproductive system
penis - deposits sperm into the females vagina during copulation
sperm duct - carries sperm from tests to the urethra
testis - produces sperm / site of sperm production
urethra - a tube which transports sperm out through penis
what are the parts of the human female reproductive system
ovary, ooterus, vagina (lol), oviduct, uterine lining and cervix
what are the functions of the structures of the female reproductive system
ovary - site of egg production
oviduct - site of fertilisation
ooterus - where the embryos grows and develops into a foetus
uterine lining - where the fertilised egg implants
vagina - where sperm is deposited by penis during copulation
structures of sperm
sperms are designed for swimming towards egg for fertilisation
tails, head, nucleus and mitochondrion
-small cell
-tail for swimming
-many mitochondria for ATP
structure of egg
designed to develop into an embryo once fertilised
nucleus, yolk and cell membrane
-large cell
-contains nucleus
-contains yolk which acts as a food source for developing embryo (after 6-8 weeks placenta is formed)
what is fertilisation
fertilisation is the fusion of the nuclei of two haploid gametes to produce a diploid zygote (diploid zygote is the single cell formed immediately following fertilisation)
what is a zygote
a diploid cell resulting from the fusion of two haploid gametes
what is a placenta
a accessory organ to provide nourishment to the developing embryo. The mothers and the embryos circulation are separate but close enough for exchange of materials.
name two materials which pass from the mothers blood to the embryo and two from the embryos to the mothers
mother -> embryo
variety of nutrients and oxygen
embryo -> mother
variety of waste products and CO2
what is continuous variation
continuous variation can be measured and there is a wide range of values between two extremes (from minimum and maximum)
Continuous variation is controlled by many genes all interacting together - polygenic inheritance
measured in a line graph
e.g. height, weight, hand span, shoe size
what is discrete variation
discrete variation is clear cut and is easily observed
these characteristics can be put into distinct categories
discrete variation is controlled by a single gene - single gene inheritance
(represented in bar graph)
what are genes
a gene is a section of DNA which codes for a protein
what are genes
a gene is a section of DNA which codes for a protein
what is a phenotype
the outwards appearance of an organism, the physical characteristics
(e.g. brown hair, Caucasian)
what is a genotype
the genes that an organism processes
(e.g. Bb, FF)
what does dominant mean
a dominant allele always shows up in the appearance of an organism
(written as capital letters)
what does recessive mean
a recessive allele only shows up in the appearance of an organism if it has inherited two of them
what does heterozygous mean
if an organism has two different alleles of a gene it is said to be heterozygous
(Aa)
hetero like heterosexual, different genders = different letter case
what does homozygous mean ?
if an organism has two identical alleles of the same gene it is said to be homozygous
(e.g, homosexual, same gender = same case )
what is allele
different forms of the same gene
e.g brown, blue or green eye colour
what goes in the top left corner of a punnet square
P = parent generation
F1 = first offspring generation
F2 = second offspring generation
why are the phenotype ratios predicted in a punnet square not always achieved in a real life scenario
because fertilisation is a random process with an element of chance
what is a genetic disorder ?
a disease caused by genes - hereditary
name 4 genetic disorders
cystic fibrosis
sickle cell anaemia
Huntington’s disease
haemophilia
what is cystic fibrosis
lung bogeys - causes respiratory and GI system to produce too much mucous
affects numerous organs
very serious
CAUSED BY RECESSIVE ALLELE
what is Huntington’s disease
causes neurons to deteriorate
make it very difficult for body to coordinate thoughts and movements
very serious
CAUSED BY A DOMINANT ALLELE
what is haemophilia
blood has trouble clotting
make it very difficult for body to stop bleeding
can be very serious
CAUSED BY A RECESSIVE ALLELE
what is sickle cell anaemia
red blood cells become crescent shaped and clogs vessels
makes it difficult to transport oxygen - hypoxia
very serious
CAUSED BY A RECESSIVE ALLELE
what is sickle cell anaemia
red blood cells become crescent shaped and clogs vessels
makes it difficult to transport oxygen - hypoxia
very serious
CAUSED BY A RECESSIVE ALLELE
