Bio 5

B15,B16,B17

asexual vs sexual reproduction definitions

• asexual - o process resulting in the production of genetically identical offspring from one parent

• sexual - a process involving the fusion of the nuclei of 2 gametes to form a zygote and the production of offspring that are genetically different from each other

advantages of asexual reproduction

• faster reproduction

• consistent offspring

• energy efficient

• no need for pollination (for crops)

disadvantages of asexual reproduction

• no genetic diversity

• vulnerable to disease

haploid vs diploid

• haploid - nuclei of gametes - 23 chromosomes

• diploid - nucleus of zygote - 46 chromosomes

advantages + disadvantages of sexual reproduction

• Advantages -

• increased genetic diversity

• less vulnerable to disease

• Disadvantages -

• slower process

• requires the fusion of 2 gametes

species definition

a group of organisms that can reproduce to produce fertile offspring

label

• A - Stamen

• B - Anther

• C - filament

• D - petal

• E - Sepal

• F - Stigma

• G - Style

• H - Carpel

• I - Ovary

• J - Ovules

functions of the anther, filament, stigma, style

• anther - contains pollen (male sex cell)

• filament - supports the anther

• stigma - the sticky surface that catches pollen

• style - links stigma to ovary

functions of the petal, speal, ovary, ovules

• petal - brightly colored in insect pollinated flowers to attract insects

• sepal - protects the unopened flower

• ovary - protects ovum (female sex cell)

• ovules - found inside ovary and contains female sex cell

pollination definition

the transfer of pollen grains from an anther to a stigma

fertilization - flowers

occurs when a pollen nucleus fuses with a nucleus in an ovule

structural adaptations of insect pollinated flowers

• large + bright petals to attract insects

• moderate number of pollen + large, sticky and spiky

• scent + nectar is present to attract insects

• stigma is sticky and inside the flower

• anther is inside the flower and firmly attached

structural adaptations of wind pollinated flowers

• small + dull petals

• large amounts of pollen + smooth, small and light

• scent + nectar is absent

• a feathery stigma outside the flower

• an anther outside the flower swinging loose

factors that affect the germination of seeds

• oxygen - for respiration to release energy for growth

• water - causes seed to expand and activates enzymes within embryo to initiate growth

• temperature - increases rate of germination, the enzyme catalyzed reaction temperature-dependent, up to an optimum

label

• A - urethra

• B - penis

• C - testes

• D - prostate gland

• E - sperm duct

• F - scrotum

state the functions of the male reproductive system : urethra, penis, testes, prostate gland, sperm duct, scrotum

• urethra - tube which allows excretion of urine and semen from the body

• penis - passes urine out of the body + allows semen to pass into the vagina

• testes - produces sperm (male gamete) and testosterone (hormone)

• prostate gland - secretes nutriative fluid which combines with sperm to form semen

• sperm duct - tube that carries sperm from the testes to the urethra

• scrotum - holds the testes outside the body to keep it colder than body temp.

label

• A - oviduct

• B - ovary

• C - uterus

• D - cervix

• E - vagina

state the functions of the female reproductive system : oviduct. ovary, uterus, cervix, vagina

• oviduct - place where fertilization takes place, connects the ovary to the uterus,

• ovary - where egg cells (female gametes) are produced

• uterus - place where fetus develops

• cervix - ring of muscle that keeps the fetus in place during pregnancy

• vagina - entry point for penis

adaptive features of sperm

• mitochondria to provide energy for movement

• flagellum to swim towards the egg cell

• enzymes in the acrosome to break down the protective layer around an egg

adaptive features of egg cells

• jelly coat that changes after fertilization(to prevent multiple sperm from entering the egg)

• cytoplasm containing energy stores to support early development after fertilization

compare female + male sex cell in terms of structure, size, motility and number

• sperm - small, head region + flagellum, can move, many produced

• egg - large, round cell with jelly coating, can’t move on its own, only released once a month

role of testosterone in males

• growth of penis + testes

• growth of facial + body hair

• muscles develop

• voice deepens

• testes start to produce sperm

role of oestrogen in females

• breasts develop

• body hair grows

• hips get wider

• menstrual cycle begins

menstrual cycle

• ovaries release an ovum every 28 days

• uterus lining thickens in preparation for embryo implantation

• if ovum is not fertilized uterus lining breaks down

• the unfertilized egg cell together with the old uterus lining are passed out of the vagina

menstrual cycle changes in uterus and ovaries from day 0-28

• 0 - menstruation - ovary - follicle

• 7 - maturing follicle

• 14 - uterus lining builds up + ovulation (follicle releases egg)

• 21 - lining continues to build up + is maintained, corpus luteum - ovary

• 28 - corpus luteum breaks down if ovum is not fertilized, new cycle

sexually transmitted infection definition

an infection that is transmitted through sexual contact

human immunodeficiency virus (HIV)

• a pathogen that causes an STI

• HIV infection can lead to AIDS

how HIV affects immune system

• HIV avoids being recognised by repeatedly changing its protein coat

• the virus infects a certain type of lymphocytes

• reduces the number of lymphocytes

• decreases body’s ability to fight of infections → AIDS

how is HIV transmitted

• unprotected sexual intercourse

• sharing needles with an infected person

• blood transfusions with infected person

• from mother to fetus through placenta

• from mother to baby via breast feeding

How to control the spread of STI’s

• limiting the number of sexual partners

• using condoms

• getting tested if unprotected sex or sex with multiple partners has occurred

• raising awareness through education programs

• abstinence from sexual intercourse

• using sterilized needles instead of sharing

chromosomes

made of DNA which contains genetic information in the form of genes

gene + allele definition

• gene - a length of DNA that codes for a protein

• allele - an alternative form of a gene

inhertience of sex

• 23rd chromosome pair - XX=female, XY=male

• egg cells carries X

• half of sperm carry X other Y

haploid vs diploid nucleus

• haploid - single set of chromosomes

• diploid - 2 sets of chromosomes

diploid cell

• there is a pair of each type of chromosome

• in human diploid cell - 23 pairs

mitosis

• nuclear division giving rise to genetically identical cells

• an exact replication of chromosomes occurs before mitosis

• the copies of the chromosome separate, maintaining the chromosome number in each daughter cell

role of mitosis

• growth + repair of damaged tissues

• replacement of cells

• asexual reproduction

meiosis

• reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells

• involved in the production of gametes

inheritance

the transmission of genetic information from generation to generation

genotype vs phenotype

• genotype - the genetic makeup of an organism, including all of its genes + alleles

• phenotype - the observable features of an organism

pure breeding

2 identical homozygous that breed together

heterozygous

• having 2 different alleles of the same gene

• no pure breeding

dominant vs recessive allele

• dominant - an allele that is expressed if its is present in the genotype

• recessive - an allele that is only expressed when there is no dominant allele of the gene present in the genotype

variation definition

differences between individuals of the same species

continuous vs discontinuous variation definitions

• continuous - results in a range of phenotypes between 2 extremes(e.g body length)

• discontinuous - results in a limited number of phenotypes with no intermediates (e.g blood type)

mutation

• a genetic change

• the way new alleles are formed - ionising radiation, certain chemicals

genetic vs phenotypic variation

• genetic - the differences in genetics among individuals of the same species (e.g blood group, eye colour, gender, ability to roll tongue)

• phenotypic - the variability of phenotypes within a population caused by either genetics or environment

what is genetic variation in populations caused by

• mutation

• meiosis

• random mating

• random fertilization

adaptive feature definition

an inherited feature that helps an organism survive and reproduce in its environment

natural selection

• a process where within a population there is genetic variation and many offspring are produced

• as these offsprings grow they face a struggle for survival (e.g competition for resources)

• Individuals that are better adapted → higher chance of surviving + reproducing

• these individuals pass on their alleles to the next generation leading to a gradual change in the population overtime

example of natural selection - bacteria

the development of strains of antibiotic resistant bacteria

selective breeding

• humans choose individuals with desirable features which are then bred together to produce the next generation

• from the new generation only individuals with the desired features are chosen

why do we do selective breeding in crop plants

• disease resistance in food crops

• increase crop yield

• adaptation to challenging weather conditions

• improvement in taste of fruits

• cultivation plants with large/unique flowers

why do we use selective breeding on animals

• cows, goats and sheep that produce large amounts of milk/meat

• chickens that lay large eggs

• domestic dogs with a gentle nature

• sheep with good quality wool

• horse with fine features + great speed

natural vs artificial selection

• natural - occurs naturally, results in adaptations that increase chance of survival + reproduction in a specific environment, can lead to gradual change + diversification over time

• artificial - occurs with human intervention, focuses on traits that are desirable to humans, can result in rapid changes in traits within a population

How to do a test cross

• using the homozygous recessive in a cross to determine if parent is heterozygous or homozygous dominant