Module 5 - Hereditary Flashcards
Follicular phase
development of an ovum-containing follicle.
Ovulation
The rupture of the follicle and the release of the ovum into the fallopian tubes.
Luteal phase
The formation and disintegration of the corpus luteum, a
hormone-releasing structure.
GnRH (gonadotropin releasing hormone)
triggers the pituitary
gland to release FSH and LH
Asexual reproduction
type of reproduction that requires only one parent to make offspring. the offspring are usually identical to the parent. e.g bacteria.
sexual reproduction
Type of reproduction that combines genetic material from two parents to form offspring. the offspring vary from parents.
what is a clone
a genetically identical copy of an organism. This can be naturally created through some forms of Asexual reproduction.
what is a haploid cell?
Haploid cell contains only one copy of each chromosome. this results in haploid cells having half the regular number of chromosomes found in a given organism . haploid cells are created by a special type of cell division called meiosis. when haploid cell combines with haploid egg, the egg is said to be fertilised and is no longer haploid ( now diploid).
what is a diploid cell?
The genetic material of two Haploid Gametes combine to create a diploid cell (a cell with two copies of each chromosome). Diploid cells contain a full set of chromosomes for the organism.
what is a gamete?
A sex cell.
what is External fertilisation?
the eggs of such animals are fertilised by sperm outside the females bodies. This is still considered sexual reproduction and is done mostly in aquatic animals.
what is Internal fertilisation?
when the male transfers sperm directly into the females to fertilise her eggs. most common in land animals.
What are some advanatges of internal and external fertilisation?
Internal fertilization protects the fertilized egg or embryo from predation and harsh environments, which results in higher survival rates than can occur with external fertilization. External fertilistaion results in larger genetic variation as sperm can fertilise multiple females.
What are some disadvantages of internal and external fertilistaion?
Internal fertilsiation results in fewer offspring due to fewer chances of fertilistaion, and external fertilisation is disadvantaged as it is exposed to the environment (predators etc) resulting in a lower survival rate.
what is a zygote?
A fertilised egg.
Mammal classification
mammals are a class of organisms that have several common features, including being warm blooded, having fur or hair and nourishing their offspring with milk. however mammals also differ in the ways they give birth.
placental mammals
the embryo grows inside the uterus, and a placenta allows nutrients and oxygen to be supplied and wastes to be removed via the mothers blood.
- offspring is usually more developed
- longer pregnancy
- animals such as humans, dogs and whales.
Marsupials
These mammals also have placentas to support internal embryonic development however they give birth to tiny, partially developed babies that continue to develop after birth, typically in the mothers pouch.
- quolls, kangaroos and koalas
Monotremes
they lay soft shelled eggs from which a very small puggle (baby) emerges and continues to grow and be nourished by the mothers milk.
- platypus and echidna
what is the menstrual cycle?
is the period during which the ovum matures, moves along the Fallopian tubes and is released, unless fertilised where it will implant in the uterus.
what is the endometrium?
Uterine lining
what is the corpus luteum?
A mass of cells that forms in an ovary. it is a temporary organ that appears every menstrual cycle and disappears once fertilisation does not occur. this organ produces progesterone and oestrogen to keep the uterine lining. corpus luteum develops after an ovum has been discharged.
Oestrogen hormone
thickens the lining of the uterus/endometrium
progesterone hormone
stabilises the lining of the uterus. Also changes the woman body once pregnant.
Follicle
A small, fluid filled sac in the ovary that contains one immature egg. During ovulation the follicle releases chemicals to encourage the nearby fallopian tube to surround the follicle. the egg then bursts through the follicle.
FSH (Follicle stimulating hormone)
Stimulates the follicle in the ovary to grow and prepare the eggs for ovulation.
LH (luteinising hormone)
Causes the egg to burst out of the follicle.
HCG (human chorionic gonadotrophin)
Released by the embryo to sustain the corpus luteum during pregnancy.
Order of hormones during ovulation?
- brain signal
- GnRH is like a starter signal for ovulation. it comes from a part of the brain called the hypothalamus. - the pituitary glands response
- when the GnRH is released, it travels to the pituitary gland, another small structure in the brain. the pituitary gland responds to the GnRH by releasing two important hormones (FSH and LH) - FSH and LH’s role
- FSH and LH work together to prepare the ovaries for ovulation. FSH helps stimulate the growth of a special structure in the ovaries called a follicle. inside the follicle is a matured egg. - LH surge
- as the egg inside the follicle gets ready, there is a surge in LH. This LH surge is like a ‘go’ signal for ovulation. it tells the follicle to release the mature egg. - ovulation
- when the LH surge happens, usually around the middle of the menstrual cycle, the mature egg is released from the ovary. this is ovulation. the egg is now ready to travel down the fallopian tube, where it ca meet the sperm for fertilisation.
what is oxytocin?
A natural hormone that manages sexual arousal, recognition, romantic attachment and mother-infant bonding. your hypothalamus makes oxytocin, but your posterior pituitary gland stores and releases it into your bloodstream.
Describe process of hormones during first trimester of pregnancy.
- HCG (formed by the embryo) rises rapidly
- HCG maintains the corpus luteum, allowing it to continue secreting progesterone and oestrogen.
- Progesterone and oestrogen interact with the hypothalamus and pituitary gland, causing a decrease in GnHR, FSH and LH. - This prevents menstruation or ovulation occurring.
- Progesterone also stimulates changes in the mother’s body. E.g. breast growth, enlargement of the uterus.
Describe process of hormones during second trimester of pregnancy.
- Production of HCG declines.
- Placenta producing oestrogen and progesterone now.
Describe process of hormones during third trimester of pregnancy.
- Oestrogen increases inducing receptors to form on the uterus wall that can bind with oxytocin.
- Progesterone inhibits oxytocin so progesterone levels drop at the very end of the pregnancy.
- Oxytocin is vital to trigger and maintain labour.
- Baby and mother’s pituitary glands produce oxytocin during labour causing muscular contractions.
what does cortisol hormone do during pregnancy?
- released by placenta
- helps baby’s lungs to mature
what does the relaxin hormone do during pregnancy?
- produced by placenta
- relaxes the bones and cartilage of the pelvis making the exit wider for the baby.
what does prostaglandins do during pregnancy?
Other tissues, including the amniotic sac, release prostaglandins, causing thinning and softening of the cervix in preparation for birth, and helping to bring on labour contractions.
what does the prolactin hormone do during pregnancy?
produced in the second half of pregnancy, stimulates milk production in the breasts. (lactation)
Name and label flower structure diagram
describe the process of reproduction in a flower
- Pollen (contains male gamete) travels from the anther to a stigma.
- Pollen germinates and a pollen tube grows down the style to the ovary.
- The pollen generative cell nucleus divides to form two sperm cells.
- Both sperm cells enter one of the ovules.
- One fertilizes the egg, the other combines with the polar nuclei to form the endosperm that provides nourishment for the zygote.
- The ovule then matures into a seed.
Ovary swells into a fruit.
what is Progestin?
a synthetic form of progesterone found in contraceptive pill.
how does the contraceptive pill work?
- The pill prevents pregnancy by releasing oestrogen and progesterone.
- The progestin molecule inhibits luteinising hormone (LH) secretion. Without the LH surge, ovulation doesn’t occur, and no ovum is released.
- Progestin also makes the lining of the uterus inhospitable to implantation of an embryo.
- The last 7 pills are sugar pills (no hormones). They are necessary to bring about menstruation.
what is a gymosperm
Any group of vascular plants that produce naked seeds not enclosed in an ovary.
for example cones.
gymosperms/cones reproduction.
pollen from male cone is blown by wind to female cone. The pollen tube forms, allowing pollen to migrate towards female gametophyte. upon fertilisation a diploid zygote forms (creates a seed)
- female cones are shorter and rounder, usually found on upper branches of tree
- male cones are longer and narrow and found on lower branches.
ferns and mosses cycle diagram
insert diagram
- gametophyte is the haploid structure
sporophyte is diploid
prokaryotic definition
Prokaryotes are organisms whose cells lack a nucleus. Have their DNA as a single looped circular chromosome and have some additional small circle of DNA called plasmid.
eukaryotic definition
Eukaryotes are organisms whose cells contain a nucleus and other membrane-bound organelles. Have multiple linear chromosomes that are not looped and are contained in the nucleus. The DNA is tightly coiled around a histone protein (so it can fit in the nucleus)
asexual reproduction: rhizomes
a stem that grows underground. it usually grows horizontally. since its a stem it has nodes and is able to put out other stems, usually straight up and above the ground. This means what looks like a bunch of individual plants above ground may be the same below ground. examples are ginger and turmeric.
asexual reproduction: runners
An above ground stem that develops horizontally along with soil. It produces roots and aerial branches that go upwards in certain points called nodes. example strawberry plant.
asexual reproduction: Tubers
A short fleshy usually underground stem bearing minute scale leaves, each of which bears a bud in and is potentially able to produce a new plant. example: potato plant
asexual reproduction: cuttings
A plant cutting is a piece of plant that is used for vegetative (asexual) propagation. A piece of the stem or root is placed into moist soil. if conditions are suitable, the plant piece will begin to grow as a new independent plant. this can happen from leaf cuttings. example: geranium plant
asexual reproduction: Budding plants
budding is inserting a single bud from a desirable plant into an opening in the bark of a compatible plant to create an advantageous variety. example: Apples, pears, peaches.
asexual reproduction: budding in protist
organisms grows from the body of its parents. Budding is the most common type of multiple fission in protists. the daughter nucleus is created and splits from parent, taking some of the cytoplasm with it. for example coral.
what is a protist
A protist is any eukaryotic organism that is not an animal, land plant, or fungus.
asexual reproduction: budding in yeast
yeast is a unicellular fungi. yeast cells devide as rapidly as once ever 90mins. a bud is formed on the side of the cell (parents body), the nucleus divides and two seperate, identical cells are formed (new organism).
asexual reproduction: binary fission bacteria
binary fission (division in half) is asexual reproduction and is most common reproduction in bacteria. in this method nucleus splits into two and then the cell splits across the middle, forming two new individual one.
asexual reproduction: fragmentation
a fragment of the parent breaks off and develops into an entirely new but genetically identical individual. the parent will then regrow the piece that broke off.
vegetation propagation
Any form of asexual reproduction occurring in plats where a new plant grows from a fragment of the parent plant or grows from a specialised reproductive structure. (such as a stolon, rhizome, tuber or bulb) this can both be natural or artificial.
Asexual reproduction advantages and disadvantages
advantages:
- takes less time + energy
- produces large number of offspring very quickly.
- no need for a mate.
disadvantages
- little genetic variation
- harmful mutations in parents will be passed down to all offspring.
what is fungi
- includes, yeast, moulds, mushrooms
- eukaryotic and heterotrophic
- obtains food by secreting digestive enzymes and absorbing dissolved molecules.
- do not photosynthesise
- main decomposer in ecosystems
spore formation
a specialised reproductive sac called a sporangium can result in the release of large numbers of tiny spores resulting in the widespread dispersal of fungi.
- fungal spores are haploid
- produced by mitosis
fungal mycelium
many branching structures that grow outwards in a circle and expands underground to seek nutrient.
binary fission diagram
protozoa
are animal like species in the kingdom of Protista. they include many parasitic protozoa which can cause disease in humans and other organisms.
daughter cell
cells that result from the division of a single parent cell.
why is DNA replication important?
helps in the inheritance process by transfer of the genetic material from one generation to another. Therefore it is required for the growth, repair, and regeneration of tissues in living organisms.
DNA structure diagram
DNA replication process
1) with the help of the enzyme DNA helicase, the double helix unwinds to form two strands.
2) the enzyme, primase, makes the starting point (primer).
3) new nucleotides are transported towards these strands and link them according to the base pairing rules. A-T and G-C (from 5’ to 3’ ends)
4) DNA polymerase is the enzyme responsible for building the new strand.
5) when fully replicated the two new double strands wind back up into the double helix form.
6) DNA ligase is the enzyme joining it all together.
7) when the two new cells are formed in mitosis, each has an identical copy of DNA structure in its nucleus.
nucleotide
A molecule that is the basic building block of the nucleic acids DNA and RNA. contains a phosphate group, a sugar group and a nitrogen base.
chromosome
a long coiled DNA molecule
gene
A selection of a chromosome with specific bases that code for a protein (there are non-coding sections also)
cell, nucleus, chromome and DNA relations diagram
Rosalind Franklin
Photographed/discovered DNA’s double helix shape.
Francis Crick and james watson
Created the DNA model as a double helix.
what are Models, purpose and limitations
what: representations of a biological reality. models can be physical models, mathematical and conceptual.
purpose:
- to explain and show how things work.
- to make predictions
- to be able to visualise structures that are not otherwise visible to the naked eye.
limitations:
- are statics so don’t represent real life moving situation.
- may be too simplistic
- size ( most are approximations or scaled)
explain cell cycle
Cells have a cycle of growth and division. Cells spend most of their time in interphase (growth phase). The M phase is division, where mitosis occurs. Interphase is divided into 3 sub phases:
G1, S , G2
Growth 1 is the first gap. Only growth occurs.
Then S phase occurs - DNA Synthesis (dna replication results in ‘X’ shaped chromosomes.
Then Growth 2 is the second gap. Only growth occurs, then
M phase: Mitosis occurs.
Cell division: Mitosis
Mitosis is a type of cell division that produces two identical daughter cells (somatic/body cells), each with the same number of chromosomes as the parent cell. It’s important for growth, repair, and asexual reproduction.
cell division: meiosis
Meiosis is cell division resulting in 4 haploid gametes. It involves 2 rounds of division:
Meiosis I (reduces chromosome number by half).
Meiosis II (similar to mitosis, separates sister chromatids).
Meiosis creates genetic diversity through crossing over (Prophase I) and independent assortment (Metaphase I).
It reduces the chromosome number from diploid (2n) to haploid (n), essential for sexual reproduction.
PMAT?
prophase, metaphase, anaphase, telophase
cytokinesis
Splitting of the cytoplasm to form two new fully complete cells.
why is mitosis important for the continution of a species?
Repair and growth to aid the reproduction and growth of an individual to survive to a reproductive age.
why is meiosis important for the continution of a species?
Creation of gametes to allow reproduction of a species.
Describe PMAT in meiosis:
Meiosis I:
Prophase I
Chromosomes condense and become visible.
Homologous chromosomes pair up (called synapsis) to form tetrads (four chromatids).
Crossing over occurs—homologous chromosomes exchange DNA, creating genetic variation.
Spindle fibers form, and the nuclear membrane breaks down.
Metaphase I
Tetrads (homologous pairs) line up along the middle of the cell (metaphase plate). (Independant assortment)
Spindle fibers attach to the centromeres of homologous chromosomes.
Anaphase I
Homologous chromosomes are pulled apart to opposite poles.
Sister chromatids stay together (unlike mitosis).
Telophase I
Chromosomes gather at opposite poles.
The nuclear membrane might briefly reform.
Cytokinesis (cell division) occurs, creating two haploid cells (each with half the original chromosome number).
Meiosis II (Division of Sister Chromatids)
Prophase II
Chromosomes condense again.
Spindle fibers form, and the nuclear membrane breaks down.
Metaphase II
Chromosomes line up single-file along the metaphase plate.
Spindle fibers attach to the centromeres of sister chromatids.
Anaphase II
Sister chromatids are pulled apart and move to opposite poles.
Telophase II
Chromatids gather at poles and decondense.
Nuclear membranes reform.
Cytokinesis occurs, creating four haploid daughter cells, each genetically unique.
Meiosis creates genetic diversity through crossing over (Prophase I) and independent assortment (Metaphase I).
It reduces the chromosome number from diploid (2n) to haploid (n), essential for sexual reproduction.
Describe PMAT in mitosis:
Prophase
Chromosomes condense and become visible under a microscope as X-shaped structures (sister chromatids joined by a centromere).
The nuclear membrane breaks down.
Spindle fibers begin to form, extending from the centrioles (in animal cells).
Centrioles move to opposite poles of the cell.
Metaphase
Chromosomes align along the metaphase plate (the center of the cell).
Spindle fibers attach to the centromeres of the chromosomes.
This alignment ensures accurate separation of sister chromatids.
Anaphase
Sister chromatids are pulled apart as the spindle fibers shorten.
Each chromatid (now an individual chromosome) moves to opposite poles of the cell.
The cell elongates as the poles move further apart.
Telophase
Chromosomes reach opposite poles. Nuclear membranes reform around each set of chromosomes, creating two nuclei.
Spindle fibers break down.
Cytokinesis (not part of PMAT but follows it)
The cytoplasm divides, forming two identical daughter cells.
gene
A section of DNA that codes for specific protein.
what is a node:
the part of a plant stem from which one or more leaves emerge, often forming a slight swelling.
tRNA
TRANSPORT RNA. T-shaped. transports amino acid to mrna as the 3 bases correspond to the 3 bases on the mrna that code for an that particular amino acid. this is called a anticodon.
mRNA
MESSENGER RNA.
rRNA
RIBOSOMIC RNA
mRNA?
Messenger RNA (mRNA) molecules carry the coding sequences necessary to complete protein synthesis, and tRNA molecules carry amino acids to the ribosomes during protein synthesis to create the polypeptide.
DNA
deoxy-ribo-nucleic-acid
transcription
Transcription is the first stage of protein synthesis, where a specific segment of DNA is copied into messenger RNA (mRNA) in the nucleus. The process begins with initiation, where the enzyme RNA polymerase binds to the DNA at a specific region called the promoter, unwinding the DNA strands. During elongation, RNA polymerase moves along the template strand of DNA, adding complementary RNA nucleotides (A pairs with U, and C pairs with G) to build the mRNA strand. Once RNA polymerase reaches a termination sequence, the process ends, and the newly formed pre-mRNA detaches from the DNA. In eukaryotes, this pre-mRNA undergoes processing, where introns (non-coding regions) are removed. Exons (coding parts) remain. The final mature mRNA exits the nucleus and travels to the ribosome in the cytoplasm, ready for translation.
ribosome
A ribosome is an intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell.
codon
3 bases which code for an amino acid
anti codon
the 3 bases at the end of the tRNA that connect to the Mrna that coded for it are collectively called an anticodon
stop codon
See table given
start codon
AUG (or see table given)
translation
Translation is the second stage of protein synthesis, where the information in messenger RNA (mRNA) is used to build a specific protein. This process occurs in the cytoplasm at the ribosome. Translation begins with initiation, where the mRNA attaches to a ribosome, and a start codon (AUG) signals the beginning of the process. A complementary tRNA molecule brings the first amino acid (methionine). During elongation, the ribosome moves along the mRNA, reading it in groups of three nucleotides called codons. Each codon matches with a tRNA carrying a specific amino acid, which is added to the growing polypeptide chain via peptide bonds. Finally, in termination, the ribosome reaches a stop codon (UAA, UAG, or UGA), ending translation. The completed polypeptide chain is released, and the ribosome and mRNA detach. This newly formed polypeptide will fold into its functional protein shape, ready to perform its specific role in the cell.
amino acid
Amino acids are molecules that combine to form proteins. In Protein synthesis, each codon specifies a single amino acid in a protein.
polypeptide
chain of amino acids
protein
made of folded up polypeptide
genotype
An organism’s genotype is the set of genes that it carries.
phenotype
Organims’s physical observable characteristics
how does the environment affcet phenotypic expression?
Environmental factors such as diet, temperature, oxygen levels, humidity, light cycles, and the presence of mutagens can all impact which of an animal’s genes are expressed, which ultimately affects the animal’s phenotype.
homozygous
2 of the same alleles, either both dominant or non dominant
heterozygous
1 dominant, 1 non dominant. The dominant allele is the one that shows
reliability
repetition
validity
the extent to which an experiment adresses/measures what it is intended to investigate.
accuracy
how accurate/exact the measurements are
Random segregation
Random chromatids separate into the newly
forming egg/sperm.
diploid number
46 chromosomes: 23 pairs
Independent assortment
The way the chromosomes line up at
metaphase is not dependent on other pairs.
types of proteins
Enzymes - Accelerates biological
reactions. Catalase speeds up the decomposition of H 2 O 2.
Transport - Transport substances from one place to another. Haemoglobin
transports oxygen from
the lungs throughout the body.
Protection - Protect cells or the organism from foreign substances. Immunoglobulins and antibodies recognise
and breakdown foreign
molecules.
Contractile - Muscle contraction.
Cell division. Myosin is one protein needed for the
contraction of muscles.
protein function/structure
Primary structure - its linear sequence of amino acids determined by DNA.
- is called a polypeptide.
Secondary structure -folding patterns within a protein chain.
Tertiary structure – the 3D arrangement of the polypeptide chain.
Quaternary structure – when multiple polypeptide chains are involved.
Exons, Introns
An intron refers to non-coding sequences found in DNA or RNA. Exons refer to the coding portions of DNA or RNA.
Uracil
one of the four bases in RNA
RNA polymerase
RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, duyring the process of transcription.
ALLELES
the different variations of a gene found at the same place
on a chromosome.
E.g. the gene for eye colour in human has alleles brown, blue, green
Genotype
the information contained in your DNA for each gene. The actual
sequence of bases determines the genotype.
Phenotype
what characteristic/trait is expressed.
Epigenetics
Epigenetics involves how chemicals in cells can change the way genes in the
DNA are expressed, without altering the DNA base sequence.
INCOMPLETE DOMINANCE
One allele does not completely dominate over another. (red and white flower making a pink flower)
CO-DOMINANCE
Both alleles are expressed. (brown and white cow)
sickle cell example for co-dominance and incomplete dominance.
The heterozygous form (sickle and normal) shows a third phenotype. Heterozygous people have both types of red blood cells so are not transporting enough oxygen to function at an optimum, however, they get enough oxygen to survive. This suggests incomplete dominance.
However, at a cellular level, both types of cells are made, suggesting co-dominance.
autosomal dominant
Autosomal dominant traits pass from one parent onto their child.
autosomal recessive
Autosomal recessive traits pass from both parents onto their child
pedigree chart
Rhesus positive and rhesus negative blood
Rhesus positive blood has a molecule (antigen) on the surfaces of
red blood cells.
Rhesus negative does not.
If a R. negative person receives R positive blood, their immune
system will target the red blood cells, because the red blood cells
have a ‘foreign’ unrecognisable molecule attached.
(Your immune system (white blood cells) attack anything that is not
recognisable as ‘self’. E.g. bacteria, foreign proteins etc.)
Rhesus positive people can be given rhesus negative blood as
there is no unrecognisable molecule attached.
O negative is the ‘universal blood type’ because everyone can
receive this type.
blood groups
A and B are co-dominant, and O is recessive
sex linked inheritance example
Colour blindness in humans is sex linked. The gene for colour blindness or
normal vision is carried on the X chromosome.
X N Y = Normal vision male
X n Y = Colour blind male
X N X N , X N X n = Normal vision female
X n X n = Colour blind female
