Reproduction in people, inheritance, variation Flashcards
Function of ovary
Production of gamete
Function of fallopian tube
site of fertilisation
Function of uterus
Site of implantation
Function of cervix
Dilates in birth
Define fertilisation
2 gametes join together
The menstrual cycle [3]
1) The cycle takes 28 days
2) Uterus lining will become thicker in preparation for embryo potentially implanting
3) No implantation the lining is shed and the cycle repeats
4 hormones for menstrual cycle
LH
FSH
Oestrogen
Progesterone
Function of FSH [2]
-Stimulates egg maturation
-Stimulates folliciles in the ovaries to secrete oestrogen
Function of LH [2]
-Stimulates ovulation
-Formation of corpus luteum
Function of oestrogen
-Stimulates the uterus to develop a lining
Function of progesterone
-Maintain and thickens lining of the uterus
-No fertilisation = levels drop and period starts
Define inheritance
The transmission of genetic information from generation to generation
DNA contains
Contains information in the form of genes
Define gene
Section of DNA coding for a protein
DNA’s shape
Double helix
Chromosomes
Super-tight bundled DNA only form at cell division
how many pairs of chromosomes
23 pairs
46 chromosomes
Diploid vs Haploid
Diploid cells are the cells that contain 2 copies of each chromosomes
Haploid cells are the cells with 1 copy of each chromosome are sex cells
DNA expression
All our cells contain the same genes, only difference between them is which genes they express (Protein made from)
(U have gene for producing insulin everywhere in ur body but cells in ur pancreas express the gene)
Alleles in organisms [2]
1) Everyone has 2 alleles for each gene
2) one on each chromosome. (Variations between people in their sequence)
Dominant allele
Controls the characteristic whenever it is present. Capital letter (B)
Recessive allele
Characteristics only show up when it is present on both chromosomes. Lower case (b)
Define phenotype
Physical appearance of an organism
Define Genotype
The set of genes (alleles) that an organism possesses
Define Homozygous
When 2 alleles are indentical
Main site of progesterone production during pregnancy
Placenta
Stem cells means
unspecialised cells that can divide by mitosis to become specialised cells
Meiosis process [2]
1) Parent cell make daughter cells that are haploid with halved chromosomes
2) 2 haploid will fuse together to form a zygote diploid that results in a genetically different gamete
Incomplete domniance means
The phenotype is a blend of both alleles
Co-dominance means… [2]
1) Both alleles in a heterozygous organism are expressed in equal parts on the organism
2) The alles do not blend, but both are expressed
Multiple allele means..
1) Involves genes that have more than two different alleles
2) A, B, AB or O
3) A > B > O (A and B are co dominance)
Linked traits means…
Traits that are linked are found on the same chromosome, this means they tend to be inherited together more frequently
Pedigree chart
Symbols to present people to show the inheritance of multiple generatij
Gene define
A length of DNA that does for protein
Gene mutation [3]
1) A RANDOM change to an organism’s DNA base sequence
2) Only true source of variation
3) Produces new alleles
Variation define
Differences between individuals of the same species
2 types of variation
1) Continuous variation
2) Discontinuous variation
Define continuous variation
Results in a continuous range between extremes of a trait (Height, body mass, skin colour)
Discontinuous variation
Results are limited to specific phenotypes with no intermediate/middleman (blood type)
Things that increase mutation rates [3]
1) Chemicals
2) Radiation
3) Infectious agents
Sources of variation [4]
1) Mutations
2) Meiosis
3) Random mating
4) Random fertilisation
Adaptive feature define
An inherited feature that helps an organism survive and reproduce in its environment
Xerophytes are…
Plants adapted for living in extremely dry soils such as in deserts
Hydrophytes are…
Plants adapted for watery habitats like rivers, ponds, and lakes
Xerophytes adaptations list [4]
1) Thick waxy cuticle
2) Needle-shaped leaves
3) Thickened stems and leaves
4) Shallow but extensive root system
Thick waxy cuticle adaptation purpose
Reduces transpiration
Needle shaped leaves adaptation purpose
Reduces surface area exposed to air
thickened stem and leaves adaptation purpose
Store water
Shallow but extensive root system adaptation purpose
Allows them to soak up water during occasional rain.
Hydrophytes adaptations list [4]
1) Air spaces
2) Flat leaves
3) Bottom of leaf submerged in water
4) Small roots
Air spaces in leaves adaptation purpose
Reduces density allow them to float on top of water with MANY airspaces
Flat leaves adaptation purpose
Maximise photosynthesis and help them float
Bottom of leave submerged in water adaptation purpose
Stomata are on the upper epidermis so they can exchange gasses
Small roots adaptation purpose
Because of plenty of water
