Heredity Flashcards

Question

Post-transcriptional RNA processing

Answer 1

The DNA which is transcribed into mRNA consists of exons (exit the nucleus) and introns. Introns are removed from the pre-mRNA, then exons splice back together and cap and tail are applied, forming the mature mRNA.

Answer 2

Levels of structures: Primary - the linear chain of amino acids that make up a polypeptide Secondary - the arrangement of amino acids. Chemical forces between nearby amino acids in the polypeptide cause it to form these unique structures. Alpha helix, beta sheet Tertiary - interactions between secondary structures and is the 3D structure of the polypeptide. Quaternary - clustering of 1+ polypeptides into a final, specific 3D shape. Categories of proteins: Fibrous - typically elongates, insoluble (e.g. keratin and collagens in skin) Globular - generally compact, soluble, spherical (e.g. insulin, haemoglobin)

Answer 3

ERM HEATS Enzymes - includes protease, amylase Repair and maintenance of body tissue - including hair, skin, eyes, muscles, organs Hormones - including insulin Energy - If body is very desperate, not enough calories, protein is broken down and used for energy Antibodies - form antibodies which assist in destroying foreign materials Transportation and storage of molecules - including haemoglobin

Answer 4

Prokaryotes; Nucleoid Single circular ring Low content Naked Few non-functional regions No introns May have transposons Also plasmids; small extra-chromosomal rings Eukaryotes Nucleus Linear (in nucleus) High content Coiled around histones Many non-functional regions Introns Many transposons DNA inside mitochondria and chloroplasts

Answer 5

Jumping genes, will move and insert themselves in different places. Pretty common in eukaryotes

Answer 6

Protein cores. Function like a spool for DNA

Answer 7

Junk DNA. found between genes, no (known) function.

Answer 8

DNA protein complex in the cytosol of Prokaryotic cells which holds DNA

Answer 9

Eukaryotes - membrane bound organelles, nucleus Nuclear DNA is linear Much of the DNA is non-functional, found between genes

Answer 10

DNA wrapped around histones which forms nucleosomes which form threads called chromatin, which squiggles into chromatin loops. These coil like a spring, making condensed chromatin loops, which wind up into chromosomes. Only visible as chromosomes- only form when replicating cell (mitosis or miosis)

Answer 11

DNA in mitochondria and chloroplasts.

Answer 12

DNA generally circular, small contents. Lies freely in cytoplasm (prokaryotes don't have a nucleus), naked (no histones) No introns Less non-functional DNA Transposons much less frequent than in eukaryotes

Answer 13

Held within nucleoid One, double stranded chromosome Chromosome contains nucleoid-associated proteins cause prokaryotic chromosomes to form looped structures

Answer 14

Many prokaryotes have plasmids; small rings of double-stranded, extra-chromosomal (outside of chromosome) DNA. Carries non-essential genes. Copied independently to chromosomal DNA. Can be transferred between bacteria

Answer 15

Observable characteristics of an organism.

Answer 16

Set of genes the organism carries

Answer 17

Continuous graduation in a phenotypic character within a species, associated with a change in an environmental variable (salt, snow, wind etc.)

Answer 18

The study of how environmental factors can change the way genes are expressed

Answer 19

Modifications to physical structure of DNA that regulate whether genes are turned on or off May be able to pass on to offspring

Answer 20

Genotype Genes provide instructions for the manufacture of proteins. Environment Limits organism’s growth and development both in development of embryo and later in life. E.g. hydrangeas in different pH Includes temp, pH, altitude Other organisms Some can change sex to ensure their group has at least male.

Answer 21

DNA methylation Addition of methyl group to part of the DNA module, locking it shut so it can't be read. Thus switching the genes off. Histone acetylation Addition of acetyl groups to histones causes DNA to bind less tightly, switching genes on.

Answer 22

Body cell. 46 chromosomes in human somatic cells

Answer 23

Not sex chromosomes

Answer 24

Constricted region near centre of the chromosome

Answer 25

Alternate forms of a gene Often a dominant and recessive

Answer 26

2 identical copies of chromosomes. Attached by the centromere (like a butterfly)

Answer 27

Sperm and ova

Answer 28

Single diploid parent cell divides to produce 2 identical diploid daughter cells

Answer 29

Carried out by germ lined cells. Single, diploid (diploid as has the genetic material from both parents) parent cell divides to produce four genetically unique haploid daughter cells. Daughter cells are haploid gametes.

Answer 30

When preparing to divide, DNA condenses into chromosomes - visualised by the process karyotyping. Dividing cells treated with chemicals to stain chromosomes and fix in place on a slide, which is viewed under the microscope and photographed. Photos of chromosomes arranged by size to produce a karyotype Number of chromosomes depends on species and cell type.

Answer 31

Homologous pair is pair with the same genes, same length, same centromere position One is maternal, one is paternal. Not identical - base sequence differs.

Answer 32

Diploid Somatic cells contain both members of each homologous pair - this is diploid. Number of chromosomes in a diploid call is 2N Haploid Gametes have only one member of each homologous pair, thus N

Answer 33

Before cell division, each chromosome must be copied by DNA replication - enough DNA for the daughter cells. This is done by mitosis

Answer 34

Groups of four chromosomes (sister chromatids and homologous pair)

Answer 35

IPMAT Interphase NOT PART OF MITOSIS Resting phase between mitotic divisions. Longest phase of cell cycle, cell absorbs nutrients, grows. DNA as chromatin, replicates. Centrosome (contains pair of centrioles) also replicates. Two centrosomes give rise to mitotic spindle; network of fibres that move chromosomes around during mitosis. Prophase Chromosomes condense into sister chromatids. Centrosomes migrate to either pole and microtubules, spindle fibres, emerge from centrioles within them. Nuclear membrane breaks, spindle fibres attach to centromere of each chromosome. Metaphase Spindle fibres align chromosomes along equator. Anaphase Spindle fibres contract, separating sister chromatids and taking them to opposite poles. Other spindle fibres, spanning width of cell, expand to stretch cell. Telophase Chromosomes reach respective poles, new nuclear membrane forms. Chromosomes decondense. Spindle fibres disintegrate. Cytokinesis After mitosis - cell splits into 2 Not a perfect split cytoplasm-wise.

Answer 36

Diploid cells which produce sex cells. Found in the gonads

Answer 37

The testes or ovaries

Answer 38

'Combined' with other chromatids by crossing over to exchange genes

Answer 39

Meiosis I Interphase occurs Prophase I: Chromosomes condense, form sister chromatids. Homologous pairs come together forming tetrads. Crossing over occurs. Nuclear membrane breaks down, centrosomes migrate to poles, spindle fibres form and attach to each chromosomes centromere. Metaphase I: Spindle fibres align chromosomes in tetrads along equator Anaphase I: Spindle fibres contract, homologous pairs separated and taken to opposite poles. Sister chromatids remain attached. Telophase I: Chromosomes reach their poles, may decondense. New nuclear membrane forms around poles. Cytokinesis - divide cytoplasm, forming two unique, haploid (each cell has only one of each chromosome pair) daughter cells. Meiosis II Starts with recombined sister chromatids Prophase II: Nuclear membrane disintegrates. Spindle fibres attach to centromere of each sister chromatid Metaphase II: Spindle fibres align pairs of sister chromatids along equator. Anaphase II: SPindle fibres contract, separating sister chromatids and pulling them to opposite poles. Telophase II: CHromosomes reach poles, new nuclear membrane formed around each pole. Chromosomes uncoil, spindle fibres disintegrate. Cytokinesis - Divide cytoplasm, producing two daughter cells from each, thus four daughter cells total.

Answer 40

Only occurs in organisms which reproduce sexually. May produce haploid gametes, which undergo fertilisation to produce a diploid zygote May produce many haploid spores, which divide by mitosis and produce unicellular or multicellular organisms (e.g. fungi)

Answer 41

Any permanent alteration in the genetic material of an organism.

Answer 42

Change in individual genes, alter the base sequence of a gene

Answer 43

Mutation with no effect on the organism, occur in non-coding DNA

Answer 44

Change to large section of or entire chromosome

Answer 45

Result of non-disjunction. Chromosome number changes due to loss or gain of chromosomes - variation in genotypes causing new phenotypes.

Answer 46

Chromosome fails to segregate correctly during mitosis (both sides of chromosome go to same place)

Answer 47

Variability in gametes, and thus in offspring Random segregation During meiosis the aligning and segregating of chromosome pairs at the equator is random. Each gamete contains maternal or paternal chromosome form each pair, which of these it is is random. Independent assortment During first division, alignment of tetrads at equator is independent of other tetrads. Thus different combinations of maternal and paternal chromosomes Crossing over Chromosomes, arranged in tetrads, exchange matching segments of chromatids. When chromatids are crossed-over a chiasma may form which allows chromosomes to exchange sections of DNA. Closer two genes are on chromosome to each other less change they will be separated during crossing over.

Answer 48

Meiosis (unique gametes) Fertilisation (unique gamete combinations) Mutations (new alleles / chromosome stuff)

Answer 49

Union of sperm and ovum. Contributes to variability as it is random which female gamete is fertilised by which male gamete. Forms zygote.

Answer 50

If mutation occurs in: Somatic cell - it only affects that organism. Germ-line cells or during meiosis - will be present in resulting gametes, mutation will be present in zygote so will be present in all cells of the organism. Point mutations can involve insertion or deletion of a base or the substitution of the incorrect base with a gene. Result is incorrect mRNA, may cause incorrect polypeptide thus different protein function. Chromosomal mutations Can involve rearrangement - incorrect exchange during crossing over Aneuploidy - chromosome number changes due to loss or gain of a chromosome. Caused by non-disjunction.

Answer 51

Aka true breeding Always produce offspring of the same type when self-pollinated (plant).

Answer 52

Homozygous Same allele (AA) Heterozygous Different alleles (Aa)

Answer 53

Not expressed if heterozygous.

Answer 54

Always expressed

Answer 55

Took 2 populations of pure-breeding pea plants with different features (e.g. white vs purple flowers) Cross pollinated two of these (by hand) P (pure-bred parent) All same flower colour as parent F1 (offspring of PwxPp) first filial 100% purple F2 (offspring of F1xF1) 75% purple 25% white Thus purple is dominant, white is recessive.

Answer 56

In punnet squares, offspring as the result of a cross

Answer 57

Use a letter to represent the alleles Capital is dominant Don’t choose S, C, O etc. Test cross - cross an unknown with a known. Do multiple squares to find possible ratios. The results vs possible ratios can assume what the unknown was.

Answer 58

Tests two traits, see if traits are inherited together or rearranged independently in the offspring Table doesn't work to predict stuff if linked genes First calculate each parent gamete possibility for each parent

Answer 59

Monohybrid In HSC ruler not needed. At MHS do use ruler. Square - Male Circle - Female Shaded - affected Generations are I, II... Individuals are 1, 2... (I1, V3 etc.) Recessive if offspring has it but parents don't If unsure can write R_ where you don't yet know if the _ is R or r. Both parents have it and kid doesn't have it is must be recessive

Answer 60

DNA inherited from the autosomal chromosomes

Answer 61

Carry the genes for physical sex of individual. Females XX Males XY

Answer 62

Some genes are on X but not Y chromosome, thus males will be more likely to express a recessive gene which is sex linked, as they only have the one allele for it. E.g. colourblindness

Answer 63

Both characteristics are expressed in the phenotype. All uppercase letters as neither is recessive. E.g. red and white cattle make roan

Answer 64

One allele for a trait not completely expressed over its paired allele. New phenotype blends both.

Answer 65

Some genes have only two alleles; dominant and recessive. Others have multiple. Likely a result of random mutations of original allele over time.

Answer 66

Multiple alleles Alleles; IA, IB or i Phenotypes; A, AB, B, O Has anti-A and/or anti-B (whichever is non-self has anti for) Surface proteins on cells allow immune system to recognise them as self or non-self. If red blood cells containing non-self antigens (e.g. adding IAIA to IBIB, the anti-B (A) antigens are non-self). AB is universal recipient - can receive A, B or O blood O is universal donor - can donate to A, B or O as there are no A or B antigens

Answer 67

Most common type of genetic variation in people Substitution of a single nucleotide. E.g. most people have A in a specified position but some have a T or G - There is a SNP at this location with three possible nucleotide variations, which are three different alleles for this position. Present in over 1% of population, otherwise mutation. Once in every 300 nucleotides Most commonly found in DNA between genes so no impact. Can act as biological markers for scientists. Apolipoprotein E ApoE gene on chromosome 19, codes for a protein which helps carry cholesterol in the bloodstream Three common alleles: e2, e3, e4 ApoE e4 allele significantly increases a person’s risk for developing Alzheimer’s disease.

Answer 68

Generation and analysis of massive-scale data sets of human genic variation (genomics or the population). Used for disease prediction, diagnosis and treatments/therapies Cystic fibrosis (CF) is genetic - 2 copies of the defective cystic fibrosis transmembrane conductance regulator gene (CFTR gene). Channel proteins present in cells, causing buildup of thick, sticky mucus in the gut and lungs. International efforts; 130 laboratories,>30 countries - online database of information on CF mutations and symptoms.

Answer 69

Single celled, prokaryotic organisms.

Answer 70

Unicellular, eukaryotic organisms. Can live in colonies.

Answer 71

Eukaryotes (uni- or multi- cellular) with cell wall but no chloroplasts or chlorophyll.

Answer 72

Fungi - Branched, tubular threads that form a filamentous network, the mycelium. Releases digestive enzymes in order to absorb nutrients from food sources.

Answer 73

Fungi - A network of hyphae, often grows underground. The body of the fungus.

Answer 74

Fungi - Capsule in which spores are produced

Answer 75

Live off dead plant / animal tissues

Answer 76

Flowering plants

Answer 77

Own flowers pollen pollinates stigma

Answer 78

Pollination between plants of the same species

Answer 79

Bacteria Binary fission Protists Binary fission (majority) and budding Fungi Budding and spores

Answer 80

Produces Two identical daughter cells (similar to mitosis) Mechanism No true nucleus; nucleoid region elongates, dumbbell shape. DNA copied, segregated to opposite ends. Fancy proteins mark middle of cell, plasma membrane pinches here to split into two cells.

Answer 81

Small bud appears as outgrowth from parent Nucleus of parent separated into two (mitosis) One nuclei shifts into bud. Bud develops eventually breaking off.

Answer 82

Asexual Spores Most common type of asexual reproduction in fungi Asexual spores produced by parent (mitosis), genetically identical to parent Budding Like protists Sexual Often response to adverse environmental conditions - chance new gene combination will be advantageous in these conditions Two haploid hyphae meet, nuclei fuse Not female/male hyphae, instead different types (like + and -) Slower than asexual reproduction.

Answer 83

Does not involve flowers, pollination or seeds. Vegetative propagation Cut part off and make it grow. Involved structures could swell with stored food. Bulbs Short underground stem, closely packed leaves around stem. These leaves are swollen with stored food. Lateral buds from bulb product new plants Rhizomes Stems which grow horizontally under ground, can be swollen with food reserves. Terminal bud turns up, producing flowering shoot and lateral buds which may grow out into new rhizomes. E.g. Ginger. Runners Stems which grow horizontally above ground. Terminal buds touch the ground and take root forming new plants. E.g. spider plant

Answer 84

Protect the bud

Answer 85

Advertise flower to pollinators

Answer 86

Holds up the anther

Answer 87

Contains sacs of pollen

Answer 88

House the cells that develop into sperm

Answer 89

Holds up stigma

Answer 90

Sticky surface, catches pollen

Answer 91

Contains 1+ ovules

Answer 92

Developing egg and supporting cells

Answer 93

Angiosperms have flowers which ensure pollination, fertilisation, and seed dispersal. Most flowers have male and female parts, some have separate male/female flowers, some have separate male/female plants.

Answer 94

Transfer of pollen form anther onto the stigma (often of different flower) of same species. Flowers can be self pollinated, or pollinated by insects, birds or wind - structure of flower reflects this. Self pollination If stigma is lower than anther pollen can fall onto own stigma, this is self pollination, so offsprings are similar to parent. To prevent this: Some discharge pollen before stigma is mature, or opposite Pollen may die upon falling onto own stigma Separate male/female flowers or plants. Cross pollination Pollination by pollen of another plant of the same species. Sexual reproduction Wind pollination E.g. grasses Anthers on long filaments with lots of very light pollen. Stigmas very large and feathery, limited colour, no nectar, no distinctive sepals. Animal pollination Brightly coloured, scented, sugary nectar, pollen may be eaten by animals. Some have landing pads or guiding patterns. Animals seek nectar, picking up pollen in this process and carry it to other plants

Answer 95

Pollen grain lands on stigma > Tube grows down from grain to ovule > two male gametes pass down this tube, one unites with egg cell within ovule (zygote) > ovary (and/or the receptacle) develops into a fruit containing seeds - each seed develops from a single fertilised ovule. After this flower dies.

Answer 96

Zygote has divided to become embryo. Protected by plant during early development. Ovule swells as embryo grows to make seed. Ovary swells and elongates to become fruit. Development ceases until favourable environment conditions trigger germination. Must grow away from parent and 'siblings' - otherwise competing for same resources. Wind, animal (eat), animal (fur), water Can be dispersed by; animals who eat the fruit or carry seeds on fur/feathers, wind, water.

Answer 97

If a species is to survive it must produce more of its own species to replace those that die; Gametes must be brought together upon maturity Moisture present for fertilisation and early development Sufficient food and shelter for offspring until they are able to fend for themselves Oxygen Dispersal of young Enough offspring reach maturity to replace numbers from previous generations which die Asexual reproduction Offspring genetically identical to parent. No need to find a mate Lower resilience to change of environment Small amount of variation within species - mutations. Bacteria; horizontal gene transfer to spread new genes throughout a species Sexual reproduction Gametes combine to form zygote. Often needs a mate Genetic variation in offspring - population more able to cope with environmental changes.

Answer 98

Union of two gametes Ovum larger, unable to move. Sperm smaller, mobile. Requires moist environment.

Answer 99

Direct transfer of gametes

Answer 100

Aquatic environments as water ensures gametes do not dry out. Release gametes directly into water. Produce a large amount of gametes as they are unprotected (both gametes and offspring) and unlikely for sperm and egg to actually meet successfully - also means more variation. Increase chance of fertilisation: Synchronise timing of gamete production and release; based on temp, day length etc. Cyclic reproductive behaviours Courtship and mating behaviours in animals Lots of young produced as poor chance of survival: Predation Lack of parental care Changes in temp, light, currents

Answer 101

On land body provides the needed moist environment. Copulation. Greatly increases chance of fertilisation - less gametes needed. Fewer eggs produced. Fewer young as higher survival rate (more parental care).

Answer 102

Chemical messengers secreted by endocrine glands into the blood (for humans, or similar system). Main sex hormones in mammals; androgens, oestrogen, progesterones

Answer 103

Mammalian sex hormone Controls development and function of male sex organs and secondary sex characteristics Testosterone development and functioning of the male reproductive system, including sperm production

Answer 104

Mammalian sex hormone Controls development and function of female sex organs and secondary sex characteristics. Ovarian function - fertility. Promotes repair and growth of uterine lining.

Answer 105

Play a role in pregnancy. Stimulate milk production in the mammary glands. Maintains thickened uterine lining (endometrium). Prevents uterine contractions

Answer 106

Males Mature sperm cells produced by spermatogenesis. Meiosis occurs in sperm tubules of the testes, stored until mature. Sperm; head with haploid nucleus and tail. Testes produce millions of sperm daily Females Mature ova are produced in ovaries by oogenesis. Before birth, cells in the ovaries called oogonia undergo repeated mitotic divisions to form oocytes, immature eggs. Each enclosed in a fluid filled cavity, a follicle. Born with 1-2 million follicles A follicle matures and releases an oocyte every 28 days until menopause.

Answer 107

Changes in response to hormones to prepare uterus for pregnancy. If no pregnancy, uterine lining is shed - menstruation. Follicular phase Menstruation, follicle development. FSH (follicle stimulating hormone) increases - grows follicle around egg. Ovarian follicle growth triggers increasing oestrogen - repair and growth of uterine lining. Peak in oestrogen triggers luteinising hormone (LH) surge Ovulation Triggered by luteinising hormone surge. Follicle ruptured (now corpus luteum), egg released. Mid cycle; day 14 Luteal phase Progesterone increases - maintain thickened uterine lining, prepare for implantation of fertilised egg. If no fertilisation, progesterone levels drop so uterine lining is shed.

Answer 108

Sperm and ova fuse Copulation; ~300K sperm introduced to vagina. Contractions of vaginal wall and whipping tail of sperm propel sperm towards cervix. High oestrogen levels before ovulation - fertile cervical mucus. Cervix > Uterus > fallopian tubes. Egg releases progesterone which sperm detects and follows. Reaches egg; sperm releases digestive enzyme to form a pathway through the layer of follicle cells and the zona pellucida (jelly-like coating around egg). Upon contact with egg, plasma membranes of sperm and egg fuse- change in egg plasma membrane, prevents further sperm entering the zona pellucida, completes egg development to form ovum. nucleuses fuse; zygote.

Answer 109

Zygote undergoes repeat mitotic divisions. 5-6 days; ball of cells; blastocyst hatches from zona pellucida and begins implantation in uterus Implantation window; 7-10 days post-ovulation Progesterone increase from corpus luteum; Endometrium thickens, becomes vascularised, gland secretions to nourish blastocyst. Outer layer of blastocyst secretes enzymes to digest endometrial tissue and sends out small projections to penetrate and adhere. Secretion of immunosuppressants to prevent rejection of embryo and prevent menstruation. When embryo contact with maternal blood supply; placenta formed.

Answer 110

Human Chorionic Gonadotrophin (hCG) One blastocyst implanted, this is hCG is produced; keeps corpus luteum active - produces oestrogen and progesterone to prevent shedding of the womb lining. Relaxin Surge and peak around end of first trimester. Relax ligaments and muscles; body stretched to accommodate growing foetus. Progesterone First weeks; produced by corpus luteum. Suppress maternal immune response to prevent rejection of blastocyst increase blood flow to womb; growth of existing blood vessels help establish placenta (nutrients for embryo) 6-9 weeks; Placenta produces most progesterone. Rising levels Strengthen pelvic wall muscles (prep for labour) Prevent womb muscles contracting before labour Prevent lactation Oestrogen Corpus luteum then foetus and placenta levels increase steadily until birth Stimulate and maintain production of other pregnancy hormones correct development of foetal organs (lungs, liver) promote maternal breast tissue growth

Answer 111

Physical strain on foetus and uterus - release stress hormone cortisol from both. Triggers rise in steroid hormone oestriol, inhibits synthesis of progesterone by placenta. Prostaglandins secreted by uterus initiate labour and decrease progesterone. Drop in progesterone - uterine contractions push foetus against cervix. Stretches and mechanical receptors send nerve impulses to hypothalamus (brain) to trigger release of oxytocin. Stimulates further uterine contractions. POSITIVE FEEDBACK LOOP Contractions get stronger until birth finished. Oxytocin levels remain high to deliver placenta.

Answer 112

Organism's complete set of DNA. Includes all genes.

Answer 113

Study of individual genes and their functions, including inheritance. Involves sequencing and analysing genomes by technologies.

Answer 114

process of determining the precise order of bases within a DNA molecule. Can compare DNA of different individuals. An entire human genome can be sequenced in days.

Answer 115

Aka. DNA fingerprinting, DNA testing Produces a unique genetic profile/fingerprint for each individual. Using DNA to distinguish between two individuals is difficult as 99.9% of DNA is the same across individuals; DNA coding for proteins cannot change much without rendering proteins ineffective short tandem repeats / microsatellites Among 3 million non-coding bases are regions with multiple copies of short repeating sequences, usually between 2-6 bases. Repeats a variable number of times between individuals Each individual will have unique pattern of repeated sequences, based on parental sequences. Process DNA recovery; small amount of tissue sampled. Amplified by Polymerase Chain Reaction Cutting of DNA; Restriction enzymes cut DNA at the restriction site, a particular sequences of 4-8 bases. Use of multiple restriction enzymes creates a range of DNA fragments of different sizes within a sample. Gel electrophoresis; DNA sample is sorted according to size; DNA added to well in the gel matrix then electrical current applied with negative electrode near wells - DNA is negatively charged so will be repelled from this electrode. Shorter fragments move further. Visualisation; DNA was tagged with radioactive probes so appear dark on photographic film OR fluorescent probes or dyes make bands fluoresce under UV light. Uses; Criminal investigations, paternity testing, medical research.

Answer 116

The ability to produce fertile offspring that survive to reproductive maturity and produce offspring of their own.

Answer 117

the measure of an individual's reproductive success. It is calculated as the average contribution to the gene pool made by a certain genotype within a population and the relative likelihood that these alleles will be represented in future generation.

Answer 118

It involves the meeting of special sex cells called gametes. A fertilised egg (zygote) occurs from the haploid gametes when the chromosome number changes from haploid to diploid.

Answer 119

Carry genetic information from both parents, therefore the offspring with contain a mix of parental genes.

Answer 120

(two complete sets)

Answer 121

(single set)

Answer 122

Refer to the number of sets of chromosomes within any cell - haploid (n) gamete from each parent combines to produce genetically unique diploid (2n) offspring.

Answer 123

A term used to describe all body/non-reproductive cells.

Answer 124

The union of male and female gametes (sperm and ova) can occur outside the body (known as external) or inside the body (known as internal).

Answer 125

When the animal has both male and female reproductive organs.

Answer 126

Takes place inside the body of the female and involves mate attraction and compilation, which requires energy investment and put the organisms at risk of predation, but fewer eggs need to be produced. It occurs in some invertebrate and most vertebrates.

Answer 127

Occurs in aquatic or moist terrestrial environments, to prevent dehydration of gametes, gametes must be produced in large numbers to ensure success. It occurs in most invertebrates and some vertebrates.

Answer 128

The process by which the sperm from a selected male with desirable traits is artificially transferred to the female.

Answer 129

Used to inseminate a large number of females, transport of semen is easier than transporting of a whole animal, semen can be stored for a long time.

Answer 130

Cannot guarantee 'favourable' traits to be passed on, reduced genetic variation; population susceptible to environmental changes.

Answer 131

Plants rely on external agents to carry the gametes from one parent to another, known as pollinating agents as well as external agents to disperse their seeds (wind, water, animals).

Answer 132

Where pollen grains are formed.

Answer 133

The stalk-like structure that attaches to the base of the flower and supports the anther.

Answer 134

The sticky top surface of the flower in which pollen adhere too.

Answer 135

Joins the stigma to the ovary

Answer 136

Where ovules is formed.

Answer 137

The process of gamete transfer from the male gametes in the pollen to the female part of the flower, stigma from the anthers. Once the pollen has been deposited on the stigma, a pollen tube germinates and grows down the style, carrying inside it the male gamete to and ovule contained in the ovary.

Answer 138

The transfer of pollen from the anther of a flower of one plant to the stigma of the flower of another plant of the same species. It relies on outside agents to transfer pollen from anthers to stigma (wind or water).

Answer 139

The pollination of a flower by pollen from the same flower or from another flower on the same plant. Self-pollination requires less energy.

Answer 140

The process of the transfer of pollen from one individual plant to another, whereby the pollen is carried by air currents (anemophily)

Answer 141

Involves the animal going from plant to plant, pollen grains stick to them and are deposited into the next flower. Animals can also help plant reproduction by dispersing seeds around in different areas.

Answer 142

The movement or transport of seeds away from the parent plant. The success of seed dispersal depends on the type of agent that the plant relies on.

Answer 143

The process by which an organism grows from a seed or similar structure.

Answer 144

The process by which pollen from a selected plant with desirable traits is artificially transferred to the female stigma of another plant.

Answer 145

Used to pollinate many flowers (valuable in farming), a particularly useful and easy way of breeding new varieties of plants.

Answer 146

Cannot guarantee 'favourable' trait is passed on, reduced genetic variation; populations more susceptible to the environment.

Answer 147

Only one parent is required and all genetic material of the offspring is identical.

Answer 148

Vegetative popagation

Answer 149

When a multicellular structure become detached from the parent plant and develop into new individuals that are genetically identical to the parent plant. Perennating organs are underground organs like roots or stems that contain enough stored food to sustain a plant in a dormant state.

Answer 150

Budding, spores

Answer 151

Tiny, unicellular reproductive cells that are produced in great numbers by organisms like fungi and plants - sporangia is what produces very large numbers of spores which are light and easily dispersed, traveling long distances in the wind.

Answer 152

When an adult organism gives rise to a small bud, which separates from the parent and grows into a new individual. i.e. yeast (a unicellular organism)

Answer 153

Plants: - bulbs - runners. Animals: - budding: coral - regeneration and fragmentation: flatworms, sea sponges - pathogenesis: honey bees, aphids, ants, stick insects.

Answer 154

Energy-efficient, required only one parent, no courtship required.

Answer 155

Low genetic diversity, more prone to environmental change, inhibits adaption.

Answer 156

High genetic diversity, less prone to environmental change, facilitates adaptations.

Answer 157

Energy costly, required two parents, courtship is time and resource communing.

Answer 158

Fertilisation more likely to occur, embryo protected from predators, offspring more likely to survive.

Answer 159

Higher energy requirement to find mate, less offspring produced, more energy required to raise and care for young.

Answer 160

Little energy required to mate, larger numbers of offspring produced, offspring can be spread widely; less competition.

Answer 161

Many gametes go unfertilised, offspring often not protected by parent; may die.

Answer 162

Unicellular prokaryotic microorganisms produce asexually; binary fission.

Answer 163

First cells elongate by building more cell wall, then the bacterial genome replicates and remains attached to the membrane. At the same time, any plasmids (small circular DNA) present replicate. Afterwards, they duplicated DNA begins to separate, moving towards the poles as the cell elongates and then cleavage furrow begins to form and cell wall form in cleavage furrow. Two identical daughter cells are produced.

Answer 164

Conjugation, transformation, transduction.

Answer 165

Direct transfer of DNA from one bacterial cell to another.

Answer 166

Nacked DNA is taken up from the environment by bacterial cells.

Answer 167

The use of bacteriophage to transfer DNA between cells.

Answer 168

Eukaryotic, unicellular or multicellular, heterotrophic. Hyphae are the basic structural unit at fungi Above ground = fruiting body Below ground = mycelium Reproduction methods; fragmentation, budding, spores. They can produce spores sexually in response to adverse environmental conditions; homothallic or heterothallic.

Answer 169

Eukaryotic organisms which are neither true plants, animals or fungi. Asexual reproductions methods: binary fission, multiple fission, budding. Sexually reproducing protists; syngamy and conjugation.

Answer 170

The process by which a gene is removed from one species and inserted into the genome of another species; it increases the genetic variation within a population.

Answer 171

Guaranteed to express desired traits, increased yield and nutritional value, reduce the use of harmful chemicals.

Answer 172

Offspring genetically identical - disease susceptibility, 'escape' of GMO into the wild population, trade issue with non-GMO countries, long term effects on human health are unknown.

Answer 173

GM Atlantic salmon have two genes from other species into their genome; these genes allow for the GM Atlantic salmon to grow all year round and grow 11 times faster than the average one.

Answer 174

Bacillus thuringiensis (Bt) is a bacteria species that produces a protein that is toxic to selective insect pests. This gene is isolated and inserted into cotton plants to produce a species called Bt cotton. The plant produces a 'natural' insecticide that kills pests as well as higher yield and reduction to use of harmful and expensive pesticides.

Answer 175

Fusion of haploid male and female gametes.

Answer 176

Diploid cell resulting from the fusion of gametes.

Answer 177

Early stages of cell division.

Answer 178

Inner cell mass will form the embryo, outer layer will form the placenta.

Answer 179

The attachment of the blastocyst to the wall of the uterus.

Answer 180

The state of carrying a developing embryo or fetus within the female body.

Answer 181

Developing human from fertilisation to the eight week point.

Answer 182

The smallest human cell; 50um, they cannot be seen by the naked eye. Fertile men ejaculate between 2-5mL of semen, 150 million sperm. The fastest swimmers find the egg within an hour. They are attracted by chemotaxis and thermotaxis.

Answer 183

It is the production of eggs begin before birth. Each female is born with up to 2 million eggs, but by puberty one quarter remains. During each menstrual cycle several hundred eggs start to develop and mature, but only one egg typical reaches full maturity, the remaining are discarded and the dominant one released into the fallopian tubes during ovulation.

Answer 184

Fertilisation timeline

Answer 185

A chemical substances that act as messengers in the body, coordinating many aspects of functioning, including metabolism, and reproduction.

Answer 186

An endocrine gland, attached to the base of the brain and just above the roof of the mouth. It secretes hormones that stimulate or inhibit other endocrine glands, regulating the release of their hormones.

Answer 187

The hormones that specifically affect the growth and functioning of the reproductive organs or development of secondary sex characteristics. They are produced in special tissue in the ovaries and testes and in the pituitary gland and adrenal cortex.

Answer 188

The are reproductive organs that become functional at puberty and the reproductive cycle commences. Gametes are produced in male and female gonads by a process known as gametogenesis.

Answer 189

Females fertility occurs in a cycle that is repeated all throughout the year and the animals are sexually activity all year round.

Answer 190

Androgens, oestrogen, progestogen.

Answer 191

Occurs only during periods of female fertility, commonly referred to as the animal being 'on heat' or 'in seasons' with the biological term being 'in oestrus'.

Answer 192

It controls the development and functioning of male sex organs and secondary sex characteristics.

Answer 193

The group control the development and functioning of the female reproductive system and secondary sex characteristics.

Answer 194

The most common progestogen and it plays a primary role in pregnancy. It also stimulates the secretion of milk in mammary glands and a drop in its levels plays a role in initiating menstruation.

Answer 195

They are produced by the ovaries and controlled by hormones of the pituitary regulate the ovarian cycle, menstrual cycle, maintenance of pregnancy, preparation for and maintenance of lactation and the pituitary secretes two gonadotropic hormones: follicle stimulating hormone (FSH) and luteinising hormone (LH).

Answer 196

Secreted by the ovaries it initiates the ripping of the graffian follicle and ovum in the ovary and stimulates secretion of estrogen.

Answer 197

Luteinising hormone (LH)

Answer 198

Secreted in the ovaries, it contributes to the growth and development of the endometrium and maturing of the graffian follicle.

Answer 199

Secreted in the ovaries, it causes the endometrium to thicken and become highly vascularised (lots of blood vessels) and inhibit the release of FSH and LH.

Answer 200

Selective breeding, cloning, somatic cell transfer, artificial insemination.

Answer 201

Taking the embryo of an animal and implanting it to fuse with another to have all the traits of the two animals within the genes of the offspring.

Answer 202

Sperm is taken from the male animals, and when the female animal is ovulating the insert the sperm artificially into the cervix. It occurs without sexual reproduction. Embryo transfer can also occur, wherein vivo fertilisation occurs (allowing for offspring to have all desired genes). The embryos are then flushed, and the best are then implanted.

Answer 203

Invivo fertilisation occurs (allowing for offspring to have both desired genes). It involves the female taking hormone injections to produce multiple ovum, the sperm being injected into the female for fertilisation to occur. The embryos are then flushed, and the best are then implanted into a surget animal - known as IVF.

Answer 204

Occurs in both plants and animals and involves picking the best traits for organisms to then insemination artificial to produce offspring Hydrate - the product of intense selective breeding. Hybrids vigour - show qualities superior to those of both parents.

Answer 205

A large area of genetically identical crops.

Answer 206

The result of any asexual reproduction, were the offspring is identical to its parent. Plants do this through tissue scraping and mammals (animals and humans) do this through stem cells (somatic cell transfer).

Answer 207

All plants have the same advantageous features as the original plant, value is consistent, ripen at the same time, quality is consistent, genetic modification is easily replicated.

Answer 208

All are equally susceptible to the same diseases, all susceptible to the same pests, can strip the soil of nutrients, genetic diversity of the species is reduced.

Answer 209

Animals with the best traits can be replicated, the general quality of heards can be more rapidly improved, genetically modified animals can be replicated so no specialised genes are lost.

Answer 210

Genetic diversity decrease, cloned animals will all be equally susceptible to the same disease/parasites, hybrids vigour may be lost.

Answer 211

Range from those that manipulate fertilisation like artificial insemination, IVF, artificial pollination to those that split up embryonic stem cells and involve embryo implantation like embryo splitting and cloning.

Answer 212

G1 phase, S phase (synthesis), G2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis).

Answer 213

It is the cell division that produces two daughter cells that are genetically identical to parent cells (same number of chromosomes). It has five stages: prophase, metaphase, anaphase, telophase and interphase. Ensures that every single cell contains the same genetic information which is necessary for the growth, repair and protein production.

Answer 214

The cells are not dividing. Chromosomes are duplicating but not visibly.

Answer 215

Each chromosome is visible as two identical, joined strands called chromatids. The nucleus membrane breaks down and disappears by the late stage.

Answer 216

Tapered system of microtubules stretches across the cell, forming a spindle. It then lines up at the centre of the cell and attached to spindle fibres known as the centromere. The chromatids separate.

Answer 217

The single-stranded chromosomes (chromatids) move towards opposite poles carried on the spindle fibers.

Answer 218

The spindle disappears. New nuclear membranes form around two sets of chromosomes.

Answer 219

Cell division that produces four daughter cells that are genetically different to parent cells and can only occurs in sex organs with sex cells (gametes). Stages of meiosis include: prophase I, metaphase I, anaphase I, telophase I, prophase II, metaphase II, anaphase II and cytokinesis. It ensures genetic variation within a species is maintained; this is central to a species surviving changes to the environment.

Answer 220

Cell growth where chromosomes are replicating to form identical sister chromatids joined at the centrosome.

Answer 221

Chromosomes condense, and four chromatids form (two of each). Crossing over may occur and the nuclear membrane disappears. Centrosome move and spindles forms from microtubules.

Answer 222

Homologous pairs from in tetrads line at the equator with one chromatid of each pair facing each pole.

Answer 223

The chromosomes move to opposite poles, being pulled by spindle fibers as microtubules contract.

Answer 224

It is the final step in cell division; it is the division of the cytoplasm and begins while the nucleus is completing its division. It separates the newly formed daughter nuclei and ensured that each cell has only one nucleus.

Answer 225

A unit of DNA that is usually located on a chromosome and that controls the development of one or more traits and is the basic unit by which genetic information is passed from parent to offspring. gene.

Answer 226

Are different versions of the same gene; originated as a result of a mutation.

Answer 227

The exchange of alleles between homologous chromosomes, resulting in a mixture of parental characteristics in offspring. Occurs in prophase I.

Answer 228

The chromosomes reach poles and spindle disappears. The nuclei forms and the chromosomes condense. Cytokinesis occurs and four daughter cells form, all genetically different.

Answer 229

The process of random segregation and assortment of chromosomes resulting in the production of genetically unique gametes. Occurs in anaphase I.

Answer 230

The process of random segregation and assortment of chromosomes resulting in the production of genetically unique gametes. Occurs in anaphase II.

Answer 231

Occurs as a result of mutations, crossing over, independent assortment, random segregation, fertilisation.

Answer 232

A chromosome consists of segments of DNA known as genes and they contain the instructions for the construction of a particular protein; RNA.

Answer 233

The sequence of bases is read in groups of three, called codons, with each codon representing one of the 20 different amino acids.

Answer 234

The process of the double stranded DNA molecules unzipping by enzymes and free nucleotides bind to each exposed backbone to create two identical DNA molecules.

Answer 235

The DNA molecule unwinds and the double helix separates into two single strands --> the process begins at the origin of replication sites along a chromosome which are coded with a specific sequence of nucleotides --> proteins that start the replication process detect and attach to these sections causing the two strands to separate to form a replication 'bubble'. --> at the end of each 'bubble', there is a replication fork, were the unwinding process beings and the bubble open up further in both directions --> the helicase enzyme is responsible for the untwisting of the double helix at the replication forks and breaks the bonds between the two strands of DNA --> the separated strand then acts as a template for the new complementary strand --> the beginning nucleotide chain is a short RNA chain called a primer and is synthesised by the enzyme RNA primase. Once the primer has formed, DNA polymerase enzymes add nucleotides to the end of existing chains --> the leading strand is the new DNA strand that is continuously synthesised whilst the other strand is called the lagging strand and it grows away from the replication forks and form discontinuously in a series of segments --> the DNA polymerase proofreads each nucleotide against its template removing any incorrect nucleotides or catalysing the formation of bonds to join the correct nucleotide to the DNA.

Answer 236

STEP 1: SEPARATION OF DNA STRANDS STEP 2: REPLICATION FORK FORMATION STEP 3: BINDING OF BASES TO EACH STRAND STEP 4: THE TERMINATION OF THE REPLICATION PROCESS

Answer 237

Carries the genetic information in the cell - the instructions for making all the structures and materials the body needs to function. The structure of DNA is described as a 'double helix' due to its unique shape. The building blocks of DNA are nucleotides, which consists of one phosphate molecule, a five-sided sugar molecule (deoxyribose sugar) and one nitrogen base. Sugar is always bigger than the phosphate.

Answer 238

The two strands are visible in a Y-shaped formation known as the fork replication. Each pair now require an identical half to match for the new pairs to form.

Answer 239

A term used to better understand the DNA structure. When the double helix is untwisted, it displays the molecules as if they were a ladder. The side rails of the ladder (the backbone) are alternating phosphate and sugar molecules whilst the rungs are paired nitrogen base molecules held together by a hydrogen bond.

Answer 240

The strands (the base) must now match with each a free floating nucleotides present inside the cell following the base pairing rules. DNA polymerase is an enzyme that functions in the zipping of both strands.

Answer 241

Each 'rung' of DNA ladder is formed from two nitrogen based (the four bases are adenine, thymine, cytosine and guanine). The rule is that adenine always pairs with thymine and cytosine always pairs with guanine.

Answer 242

The end of the DNA replication process.

Answer 243

Are short chains of 2-50 amino acids.

Answer 244

Linear molecules, made up of multiple peptides.

Answer 245

The functional unit, made up of one or more polypeptides.

Answer 246

A simple organic compounds containing a carboxyl and an amino group. They are the building blocks of proteins. Essential amino acids.... Must be obtained from food Nine essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine Non-essential amino acids... Produced by our bodies They include: alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, proline, serine and tyrosine

Answer 247

Small RNA molecules that transfer specific amino acid to the ribosome during the formation of polypeptides. Has a distinctive folded three-loop structure. One contains an anticodon; a sequence of three nucleotides, complementary to a corresponding sequence on the mRNA. Each tRNA has a corresponding amino acid attached to the opposite end.

Answer 248

Separating the twisted strand into two twisted strands. This is done through the helicase (a protein) that aids in the separation of strands. They are separated by breaking the hydrogen bonds between the nucleotide base pairs.

Answer 249

A set of three nitrogen bases in mRNA.

Answer 250

Complementary set of three nitrogen bases on tRNA.

Answer 251

Replication of DNA is a complex process and each step is controlled by one or more enzymes. Most changes are temporary because they are corrected by repair enzyme. They also speed up reactions by lowering the activation energy required for the reaction to occur; they hold substrate molecules in a way that makes the reaction more likely to occur.

Answer 252

DNA is linear, it is strengthened and stabilised by histone proteins, found in the nucleus, enclosed in a nuclear membrane, don't have a plasmid.

Answer 253

DNA replication --> RNA (transcription) ---> proteins (translation).

Answer 254

Polypeptides are chains of amino acids and when the chains join together, they form different proteins depending on the amino acids. They link together in a linear sequence, to form chains of up to 300 amino acids.

Answer 255

Messenger RNA (mRNA), transfer RNA (tRNA), tibosomal RNA (rRNA).

Answer 256

Occurs when an enzyme, RNA polymerase, binds to a section of DNA and begins building a chain of RNA nucleotides to form a complementary strand of RNA

Answer 257

Single-stranded nucleic acid, consisting of a ribose sugar, phosphate backbone and nitrogen base (A,U,G,C). DNA doesn't leave the nucleus; the message must be sent from the nucleus to the ribosome where protein synthesis occurs, sent in the form of mRNA

Answer 258

RNA polymerases bind to a section of DNA called the promoter and the DNA unzips. The only part of DNA unzips that contains the gene to be used.

Answer 259

Transcription of the gene is controlled by the enzyme RNA polymerase. The sense strand (non-coding strand) acts as a template and RNA nucleotides are assembled to form the complementary single-stranded mRNA molecule.

Answer 260

The mRNA then moves out of the nucleus and into the cytoplasm ready for translation.

Answer 261

Translation is the process of translating the sequence of a messenger RNA (mRNA) molecule to a sequence of amino acids during protein synthesis.

Answer 262

Translation occurs in when the ribosome moves along the mRNA molecule and as they do the tRNA molecules attach to the mRNA by temporarily pairing the bases of the tRNA anticodons with their complementary codons on the mRNA.

Answer 263

The amino acid from the tail end of each tRNA are linked to one another by an enzyme to form a polypeptide chain. Each amino acid is then spliced off its tRNA carrier.

Answer 264

DNA is circular, does not have any histone proteins, found in the nucleoid, no nuclear membrane, many have plasmids.

Answer 265

The tRNA moves away from the mRNA, leaving the growing chain of amino acid and moves back into the cytoplasm where they can pick up another amino acid and be reused.

Answer 266

The polypeptide chain is then processed in the cell and folded into the correct shape for its functioning, forming the final protein end product.

Answer 267

The mRNA is broken down into it individual nucleotides, which can be reused.

Answer 268

Structural proteins form the structure and functional part of the cell membrane (active or passive movement). They are found in body tissues that require tensile strength which is provided by the long and fibrous structural proteins. - Some proteins in the cell membrane also function in communication and regulate the movement of substances across the cell. Some proteins are responsible for cell motility, joining together to form filaments, whereas the storage and transport proteins bind and store or carry other molecules in the cell and some proteins regulate metabolic functioning: enzymes chemical messengers.

Answer 269

Apecific linear sequence of amino acids that make up polypeptide chain.

Answer 270

Regular, repeated patterns of folding of the protein backbone.

Answer 271

The overall folding of the entire polypeptide chain into a specific 3D shape.

Answer 272

Occurs when a protein is made up of two or more polypeptides. Example - haemoglobin.

Answer 273

Transport - haemoglobin, enzymes - catalase, structural proteins - intra and inter cellular, hormones - insulin, antibodies - immune system.

Answer 274

Double-stranded, circular molecule with no introns. It produces proteins required for their function and also reproduce like bacteria, replicating their own DNA and directing their own dividends.

Answer 275

Also double-stranded, circular molecule with no introns. It produces proteins required for their function and also reproduce like bacteria, replicating their own DNA and directing their own dividends.

Answer 276

The set in the DNA responsible for a particular phenotypic trait.

Answer 277

The physical expression of that trait (physically observed characteristic). It is influenced by the environment: genes + environment = phenotype and is determined by the genotype.

Answer 278

2 alleles are the same for a particular characteristic (purebred) which is seen as: TT or tt.

Answer 279

2 alleles are different for a particular characteristic (hybrid) which is seen as: Tt.

Answer 280

Overpower/mask recessive alleles. It is displayed with a capital letter as it is dominant (D).

Answer 281

Are hidden/asked by dominant alleles. It is displayed with a lowercase letter as it get dominated over (r).

Answer 282

During gamete formation, the pair of alleles for a tree segregate and each gamete receives only one allele for the trait/gene - first law (segregation).

Answer 283

When the inheritance of more than one trait/gene is studied, the pair of alleles for each trait separate independently of the other pairs of alleles - second law (independent assortment).

Answer 284

A version of each characteristic/trait in each individual is inherited from both parents and therefore controlled b a pair of factors (called alleles). The alleles pass from one generation to the next according to a set ratio The alleles in an individual may be the same (pure-breed/homozygous individuals) or may differ (hybrid/heterozygous individuals). In hybrids, a trait that is expressed is known as the dominant allele and the hidden or masked is the recessive allele. For a recessive trait to be expressed, both alleles must be received.

Answer 285

A representation of the possible genotypes of an offspring.

Answer 286

When neither allele is dominant but combined and display a new trait that is a mix of the two alleles. They are represented as two capital letters, one with an apostrophe to indicate the different allele that is involved. Example; a snapdragon flower that is pink as a result of cross-pollination between a red flower and a white flower.

Answer 287

When both alleles of a gene are dominant and the heterozygous phenotype has both traits equally expressed. Example; a red bull and a white cow produce a roan calf.

Answer 288

The presence of more than two alleles for a genetic trait. Blood types are an example of multiple alleles: A, B, O. the A and B alleles are codominant to each other and are both dominate over the O allele, making the O allele recessive.

Answer 289

Squares are used to represent males, circles are used to represent females. A line between (horizontal) a male and female indicates mating (marriage), a vertical line from the parents indicates offsprings and shading are used to indicate the individuals showing the trait.

Answer 290

An affected individual ALWAYS has one affected parent and two affected parents can have an unaffected child.

Answer 291

An affected individual may have unaffected parents and two affected parents only can have affected children.

Answer 292

The two possible sex chromosomes: X and Y. Females have a homologous pair of X chromosomes and males have one X chromosome and one Y chromosome, therefore, the father determines the gender of the embryo The sex chromosome is found on the 23rd chromosome. Hence sex-linked conditions commonly occur on the X chromosome.- males inheritance can skip a generation (grandfather to grandson for example). All sons of an affected female are also affected. A carrier has the allele that causes a condition but does not express it.

Answer 293

A term used to describe the fraction of allele copies for a particular gene in a defined population.

Answer 294

Polymorphism; refers to individuals with different phenotypes and it arises as a result of a mutation - an error in DNA replication. A point mutation in a segment of DNA that occurs in more than 1% of the population. Most are found in the introns (DNA between genes), resulting in little effect on cellular functions. If found on the exon, they have a more significant impact.

Answer 295

A GWAS rapidly scans for SNP markers across the genomes of individuals with a known disease or disorder and compare them to 'control' individuals; GWAS has identified SNPs related to conditions like cancer, diabetes, heart disease, mental illness, Parkinson's disease, Crohn's disease and Alzheimer's disease.

Answer 296

A protein that combines with lipids in the body to form molecules called lipoproteins. They are packed with cholesterol and other fats that carry them through the bloodstream. There are three alleles for the apoE gene; e2, e3 and e4.

Answer 297

The study of how the gene pool of a population changes over time, leading to a species evolving - looks at the genetic similarities and differences.

Answer 298

The sum total of all the genes and their alleles within a population.

Answer 299

The total no. of genetic characteristics in the genetic makeup of a species.

Answer 300

The tendency of individuals genetic traits in a population to vary.

Answer 301

A measure of how common an allele is within a population.

Answer 302

frequency of allele G = number of copies of allele (G) in a population / total number of copies of the gene (g + g) in the population

Answer 303

Having either one feature or another (dominant gene) which cannot cannot be changed. Examples; Mendel's peas: smooth or wrinkled, freckles in humans, eye colour.

Answer 304

Characters with a continuum of appearance due to the influence of two or more genes (recessive gene) and can be changed. Examples; height, weight, blood type.

Answer 305

Is a technique that separates the double-stranded DNA of two species into single strands. The single strands form each species are mixed and allowed to bind. They are then reheated and the temperature of separation in is recorded The more closely related species, the stronger the hybridisation, the higher the temperature required to separate the hybrid DNA.

Answer 306

Used to study evolutionary relationships and conserved DNA sequence which indicate gene that are essential to life.

Answer 307

DNA sequencing, DNA profiling, polymerase chain reaction (PCR), gel electrophoresis, genetic sequencing, genetic testing in paternity testing and forensic science, karyotyping, FISH-ing.

Answer 308

The process of determining the precise order of nucleotides within a segment of DNA.

Answer 309

The testing of highly variable regions of an individual's DNA that contains short repeating called short tandem repeats (STRs) located in the introns; non-coding regions

Answer 310

A technique used to exponentially amplify large numbers of copies of a specific sequence of DNA. It can be used to amplify unique DNA sequences of any organism which can then be compared to other nucleotide segments from a known source. It uses; genetic testing, medical diagnosis, DNA fingerprinting, cloning and evolutionary study.

Answer 311

Denaturation: DNA sample is heated to separate it into two single stands.

Answer 312

Annealing: DNA primers attach to the 3' end of the target sequence

Answer 313

Elongation: a heat-tolerant DNA polymerase binds to the primer and copies the strand.

Answer 314

A lab technique used to separate mixtures of DNA based in molecular size. The molecules are pushed by an electrical field through a gel; the smaller the molecules, the faster and further they move

Answer 315

The exact sequence of nucleotides in a chromosome or gene is determined PCR can be used to generate a DNA profile of parents concerned that they may both varying a recessive allele for a disease. This requires that the sequence of the gene be known so that specific DNA primers can be developed to target the gene associated with the disease. Once the gene is amplified using PCR and the product size is analysed on via gel electrophoresis to determine if the mutation is present.

Answer 316

Restriction fragment analysis is a technique that does not require a specific sequencing of a DNA sample. Two key steps: PCR in combination with restriction enzymes is used to amplify multiple highly variable STR regions located in the introns (non-coding). A different primer is used for each STR and gel electrophoresis is used to separate the DNA fragments. A unique DNA profile is produced for each individual. DNA profiling can be used to identify suspected from trace DNA evidence.

Answer 317

Used to detect abnormalities in whole chromosomes numbers or structural issues. Requires dividing white blood cells from the patient. Chromosomes are stained, counted, sorted into homologous chromosomes and analysed.

Answer 318

The merging of all aspects of conserve biological diversity. These include genetic diversity, species diversity and biodiversity. It is the process of managing population size, understand genetic diversity within the population and managing any habits in critical danger (species included).

Answer 319

Anthropological genetics: science of using genetic data to understand human evolution. Humans have more genetic diversity within a population than between populations. Until recently, our understanding of human evolution was based on fossil evidence, which is both incomplete and subject to interpretation. The two models used to explain human migration are the Multiregional hypothesis (MRE) and the Replacement hypothesis. Genetic data favours the Replacement hypothesis that modern humans evolved out of Africa and spread across the other continents.

Answer 320

The smallest number of individuals in a species or population capable of persisting at a specific statistical probability level for a predetermined amount of time.

Answer 321

The application of genetics to preserve species through maintaining variation within populations so that they are capable of coping with environmental change. Conservation biology + genetics = conservation genetics Scientists analyse alleles of multiple genes to examine the genetic diversity within a species. Organisms that conservation geneticists study are typically endangered or threatened due to habitat destruction, environmental change and change in population size.

Answer 322

REPRODUCTION IS THE MECHANISM TO PRODUCE OFFSPRING, IF SUFFICIENT OFFSPRING REACH MATURITY IT WILL ENABLE CONTINUITY OF A SPECIES

Answer 323

external and internal fertilisation

Answer 324

asexual and sexual reproduction

Answer 325

budding, spores

Answer 326

binary fission

Answer 327

Large number of gametes produced Doesn't require mating rituals

Answer 328

Production of so many gametes requires energy Must occur in wet environment

Answer 329

Increased likelihood of fertilisation Increased protection from environmental factors Higher survival rates

Answer 330

Mating "ritual" required Higher chance of STI

Answer 331

Quick Not energy intensive No requirement for mates

Answer 332

Clones of parents = lack of diversity More susceptible to environmental changes (being wiped out by disease)

Answer 333

Combination of different genes/traits Variation Adaptability to environment

Answer 334

Time intensive Energy intensive Mating partner Fewer offspring produced

Answer 335

Fertilisation is the fusion of gametes (ovum and sperm cells) to initiate the development of a new organism. This happens in the Fallopian tubes of a female and creates a zygote. as the zygote moves down the fallopian tubes it divides and becomes a blastocyst. The blastocyst embeds itself into the wall of the uterus which occurs about 7 days after fertilisation.

Answer 336

FSH - sourced from the pituitary gland and controls the shedding of uterus lining. Decrease dramatically when a woman falls pregnant. Oestrogen - sourced mainly from ovaries and helps regulate the functioning of the ovaries. Increases as a result of pregnancy. Progesterone - sourced from ovaries and targets the uterus. It helps maintain the uterus lining and strengthens muscles for birth. Increases as a result of pregnancy.

Answer 337

knowledge = manipulation = impact Selective breeding - through the knowledge that phenotypic traits are inheritable, farmers pick animals with desirable traits. i.e. Belgium blue cows Genetic engineering - knowledge of DNA structure and improvement of genetic technologies (e.g. transgenics) has allowed farmers to manipulate organisms on a cellular level. i.e. bt cotton insect repellence

Answer 338

Very important - otherwise may result in detrimental mutations

Answer 339

interphase

Answer 340

Interphase: Chromosomes are relaxed; Nuclear membrane is intact; During S-Phase, chromosomes are duplicated Prophase: Chromosomes condense.; Nucleus disintegrates; Centrosomes form at the poles; Microtubules extend from centrosome Metaphase: Chromosomes line up along the equator of the cell Anaphase: Microtubules pull identical chromatids apart toward opposite poles of the cell. Telophase: Chromosomes relax; Centrosomes disappear; Nuclear membrane reforms

Answer 341

Interphase: same as mitosis Prophase I: Homologous chromosomes pair up; Crossing over - creation of new gene combinations Metaphase I: Pairs of homologous pairs line up along the equator Anaphase I: Homologous pairs separate, pulled to opposite poles by the meiotic spindle Telophase/ Cytokinesis I: Two HAPLOID daughter cells are formed by cytokinesis

Answer 342

Prophase II: Chromosomes condense and the nuclear envelope breaks down Metaphase II: Chromosomes line up along the equator Anaphase II: Sister chromatids are separated by the spindle microtubules and pulled to opposite poles Telophase/ Cytokinesis II: Four HAPLOID daughter cells are formed by cytokinesis

Answer 343

Double hydrogen bond between A-T Triple hydrogen bond between G-C

Answer 344

see diagram

Answer 345

Initiation ('unzipping'): Helicase enzyme breaks hydrogen bonds between nitrogenous bases Elongation: DNA Polymerase binds at primer sites and begins to add complementary base pairs Termination: Polymerase reaches end of the molecule and falls off as two identical strands have been produced which recoil into double helix shape

Answer 346

In order to make proteins which are super important for cell and organism structure and function

Answer 347

Keratin (aka hair and nails) - important for support and structure Insulin (hormone) - messenger Haemoglobin (RBCs) - transport (of oxygen)

Answer 348

Prokaryotes - loop Eukaryotes - tightly coiled, distinct start and finish

Answer 349

DNA unwound by Helicase. RNA Polymerase links nucleotides according to DNA complementarity forming an mRNA strand. mRNA moves from nucleus to cytoplasm.

Answer 350

mRNA strand binds to a ribosome. Complementary anticodon tRNA carrying amino acids bind to mRNA codons. Polypeptide bonds are formed by animo acids until a STOP codon is reached. Polypeptide chain is released into the cytoplasm and folds into a protein.

Answer 351

Genetic information inherited from parent organisms serve as a list of instructions telling the cell what to express to create phenotypes. However, external factors can affect gene expression. Certain genes may be 'switched on' at different stages of development or only expressed un response to certain events (such as extreme heat or cold).

Answer 352

Proteins are made of amino acids which have a central carbon bound to an amine group, a carboxyl group, a hydrogen and a R-group. Amino acids are differentiated by the R-group.

Answer 353

structure and support, enzymes, antibodies, messengers, transport and storage

Answer 354

formation of gametes: meiosis (crossing over), fertilisation (combining gametes), mutation

Answer 355

autosomal, sex-linkage, co-dominance, incomplete dominance and multiple alleles

Answer 356

Co-dominance is when both alleles in a gene pair are fully expressed (e.g. a spotted brown and white cow) while incomplete dominance is when a third phenotype is created which is a blended version of both alleles (e.g. a pink rose from breeding a red and white one together)

Answer 357

Charts showing family relationships and phenotypes. It helps to trace phenotypes through generations.

Answer 358

charts used to theorise the possible gene combinations in a cross between 2 organisms

Answer 359

An SNP is when one nucleotide switches with out for a different one. Analysing SNPs allows us to generate data on population genetics. SNPs occur at different frequencies in different populations, regions, and cultural groups. E.G. sickle cell disease occurs from a substitution of A to T resulting in the codon GTG (valine amino acid) instead of GAG (glutamic amino acid). It occurs mostly in Africa and America (due to Africans being imported into American in the 15th century for slavery). A possible reason people with sickle cell disease live as long as they do, and why this SNP is so frequent is due to its correlation with Malaria resistance.

Answer 360

DNA Sequencing is identifying and analysing the sequential order of nucleotides (using the Sanger method) while DNA Profiling compares DNA from various individuals (using gel electrophoresis) to analyse similarities and differences (e.g. paternity)

Answer 361

Australian koala populations - their low population numbers resulted in inbreeding hence a loss of genetic diversity leading scientists to declare them functionally extinct. They are highly susceptible to selection pressures or genetic disease. To try and reduce the impact of this problem scientists could try to breed koalas from different areas.

Answer 362

The link between the BRAC1 & BRAC2 gene and the potential for developing breast cancer. Knowledge of carrying this gene could mean it is detected earlier. People may even get mastectomies as soon as they find out they have the gene as a prevention method. This knowledge empowers people to take control over their health.

Answer 363

Mitochondrial DNA. Mitochondria in all of the cells has unique DNA different to our actual DNA. It is inherited from an individual's mum - from the egg cells. Can be used to track ancestry. Looking at mutations in the mitochondria in DNA. Use this to look at human evolution - track the evolution of human species from Africa and where they moved and diverged.

Answer 364

occurs when multiple genes determine the phenotype of a trait

Answer 365

a relationship in which one allele is completely dominant over another

Answer 366

A pattern of inheritance in which two alleles, inherited from the parents, are neither dominant nor recessive. The resulting offspring have a phenotype that is a blending of the parental traits.

Answer 367

a polymorphism that substitutes one base pair for another

Heredity Flashcards

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