Heredity and Reproduction Lecture Notes

Flashcards on Heredity and Reproduction

Unicellular

Made of one cell

Multicellular

Made of many cells

Prokaryotic

Simple cells with no nucleus

Eukaryotic

Complex cells with a nucleus

Cell wall

A hard outer layer that protects some cells

Peptidoglycan

The material that makes up a bacterial cell wall

Chitin

The tough material in fungi cell walls

Cellulose

The material in plant cell walls

Autotrophic

Makes its own food (like plants using sunlight)

Heterotrophic

Eats other organisms for food

Saprophytic

Gets nutrients from dead things

Asexual reproduction

Only one parent; makes an exact copy

Binary fission

One cell splits into two (used by bacteria)

Budding

A small part grows off the parent and becomes new

Spore formation

Tiny cells that grow into new fungi

Vegetative propagation

New plants grow from parts like stems or roots

Self-pollination

Plant uses its own pollen to reproduce

Cross-pollination

Plant uses pollen from another plant

Elongation

A newly divided cell grows to twice its size and replicates its DNA

Roots

Tubers are swollen underground roots that store nutrients for new plants to grow

Stems

Runners are long thin modified stems that grow across the surface of the ground and give rise to new leaves/roots

Leaves

Plantlets are buds on leaves that fall off to create new plants

Apomixis

The formation of a seed without the fertilisation of an ovum

Parthenogenesis

Offspring develop from eggs that have not been fertilised by a male

External fertilisation

release of both eggs and sperm into the external environment

Internal fertilisation

sperm fertilising the egg within the female

Fertilisation

fusion of gametes initiating the development of a new organism

Hormones

chemical messengers released into bodily fluids such as blood that bind with protein receptors to activate specific cells or tissues to orchestrate short/long-term responses for bodily functions

Implantation

when a fertilised egg adheres to the wall of the uterus

Pregnancy

a period where a fetus develops inside a woman's uterus

Birth

the emergence of a baby from the body of its mother and the start of its life as a separate being

FSH (Follicle Stimulating Hormone)

Stimulates follicle growth (maturing of an egg)

LH (Leutansing Hormone)

Stimulates ovulation and the formation of the corpus luteum

Estrogen

Stimulates the thickening of the endometrium (uterine wall)

Progesterone

Maintains the endometrium (uterine wall) and prevents FSH, LH

Human Chronic Gonadotrophin (HCG)

Suppresses further egg production and maintains the uterus by stimulating the corpus luteum to produce progesterone, until the placenta is ready to produce itself

Relaxin

Loosens and relaxes your muscles, joints and ligaments during pregnancy to help your body stretch.

Oxytocin

Contraction of the womb in childbirth

Complementary nitrogenous bases

Weak hydrogen bonds hold the bases together

Structure of DNA

Each DNA strand has a sugar- phosphate backbone

Initiation

the enzyme helicase unwinds and separates complementary DNA strands by breaking the hydrogen bonds

Elongation

Primase binds to the ends of each strand, signalling the start of replication. DNA polymerase attaches to the base nucleotides of each strand to pair A-T and C-G

Termination

DNA polymerase reaches the end of the DNA molecule and two identical daughter strands are formed

Cell Cycle

Repetition of cell division and growth

G1 phase

Cell growth before DNA replication

S phase

Synthesis during which the DNA replicates

G2 phase

enzymes check for errors in duplicated chromosomes

M Phase

Mitosis Process

Interphase

DNA replicates

Prophase

Chromatin coil together and 2 identical sister chromatids attach at the centromere

Metaphase

Chromosomes line up across the centre of the cell where spindle fibres attach

Anaphase

Sister chromatids are separated at the centromere and pulled to opposite poles of the cell

Telophase

Spindle fibres break down and the nuclear membrane forms at each pole

Cytokinesis

Division of the cytoplasm forming into roughly equal parts

Telomers

Region on the end of a chromosome consisting of DNA

Prophase 1

Homologous chromosomes pair up and form a synapse between non-sister chromatids

Crossing over

sections of genes are swapped along the synapse

Metaphase 1

Homologous chromosomes line up independently along the middle

Anaphase 1

Chromosomes are pulled apart into opposite ends of the cell

Telophase 1

A nuclear membrane forms at each pole around a cluster of chromosomes and the cell begins to split

Nondisjunction

chromosomes failing to separate correctly, resulting in gametes with one extra, or one missing, chromosome

Histones

a small protein that DNA strand wraps around

Introns

sections of DNA not useful for making proteins

Plasmid

circular pieces of DNA used to make transgenic organisms like BT cotton

Polypeptides

large chains of amino acids bonded together to form a protein

Gene

sequence of DNA used to code for a polypeptide to be produced

Gene expression

total process between a gene and a functional gene product, including polypeptide synthesis and modification to form a functioning protein

Gene regulation

process in which genes are turned on and off (gene silencing)

Epigenetics

the study of inheritance patterns

tRNA (transfer RNA)

attaches to a specific amino acid at one end and has an anti-codon at the other end to recognise the mRNA strand

mRNA (messenger RNA)

carries information from the DNA in the nucleus to the ribosome

Transcription

information on a strand of DNA is copied into a new molecule of mRNA

Template/sense strand

Used as a template for mRNA to sequence base pairs

Coding/anti-sense strand

Its base sequence corresponds with the base sequence of the mRNA strand

Translation

The mRNA strand is converted to an amino acid sequence or polypeptide chain produced at a ribosome

Genotype

pair of genes that controls a specific characteristic in an organism

Phenotype

observable characteristics of an organism

Allele

two or more alternative forms of a gene

Autosomal Inheritance

Not on the X or Y chromosome

Autosomal Dominant

A trait is determined by the expression of a dominant allele

Autosomal Recessive

two recessive alleles, one from each parent, are required to be inherited in order for a trait to be phenotypically expressed

Sex Linkage

Carried on the X or Y chromosome

Codominance

when both alleles in a gene pair are fully expressed in a heterozygous individual

Incomplete Dominance

neither trait is completely expressed over its paired allele resulting in the blend of the phenotypes of both alleles in a heterozygous individual

Multiple Alleles

the presence of three or more alleles for a specific trait

Mutation (Factors Affecting Gene Pool)

changing of a gene that results in a variant form that is permanent

Natural Selection

Selective pressure makes it difficult for certain organisms to survive unless they possess a particular allele that codes for an advantageous phenotype

Genetic Drift

A change in allele frequency due to random chance

Bottleneck

A natural disaster wipes most of the population; survivor alleles increase in

Founder

loss of genetic variation that occurs when a new population is established

Gene Flow

alleles are brought into, or taken out of, a population due to immigration or emigration

Sexual Selection

when mating is not random but certain individuals are seen as attractive mates; their alleles are preferentially passed on

Analysing Single Nucleotide Polymorphism (SNP)

Variations in one nucleotide (A,T,C,G) that occur in greater than 1% of the population

DNA Sequencing

The process of determining the nucleotide sequence (A,T,C,G) of a gene on a chromosome

Oxford Nanopore

Allows for the analysis of DNA or RNA fragments

DNA Profiling

The technique used to compare individuals based on their DNA characteristics

Polymerase Chain Reaction (PCR)

Amplifies the amount of DNA of the sequence being studied

Population Genetics

The study of the gene pool changes over time, leading to the evolution

Conservation Management

Involves an understanding of how genes are inherited in a population

Gene Pool

the gene involved in the long term survival of genes