HSC biology - Mod 5 Heredity

Reproduction

Biological process where offspring are produced to ensure continuity of a species

Diploid

two sets of chromosomes; the full number of chromosomes found only in somatic cells.

Haploid

one set of chromosomes; half the number of chromosomes found only in gametes.

Asexual reproduction

Reproduction involving only one parent organism, producing genetically identical offspring.

Sexual reproduction

Reproduction involving two parent organisms, resulting in offspring with a mix of genes and higher genetic diversity.

Zygote

A fertilized cell formed when gametes from two parents gametes fuse.

Genome

The complete set of DNA (genetic material) in an organism.

Biological fitness

The average contribution an individual makes to the gene pool through its offspring.

External Fertilisation

The meeting of gametes outside the female body, typically in aquatic environments.

• more gametes produced, more genetic variation

• doesn’t require courtship

• offspring more widely spread (less competition

• gametes susceptible to predation

• gametes less likely to meet

Internal Fertilisation

The meeting of gametes inside the female body.

• higher chance of gametes meeting

• embryo protected from predation + environment

• offspring more likely to make it to sexual maturity

• high energy costs for courtship

• less offspring produced

• more energy to raise young

Binary fission

A form of asexual reproduction in bacteria where a single cell divides into two identical daughter cells.
1. cell elongates, extending cell wall
2. bacterial genome replicates + plasmids replicate
3. DNA moves to opposite poles
4. cleavage furrows, cell splits

Conjugation

The direct transfer of DNA from one bacterial cell to another through a temporary junction.

Transformation

The uptake of naked DNA from the environment by bacterial cells.

Transduction

The transfer of DNA between bacterial cells via a bacteriophage.

Syngamy

The complete and permanent fusion of two haploid gametes to form a diploid organism.

Homothallic

Organisms capable of self-fertilisation to produce sexually reproducing colonies.

Heterothallic

Organisms that require two different haploid cells to fuse and produce new individuals.

Mycelium

The fibrous structure of fungi that maximizes contact with water and digests food.

Sporangium

A special reproductive sac in fungi from which spores are released.

Oogenesis

The process of female gamete (ovum) production in the ovaries.

Spermatogenesis

The process of male gamete (sperm) production in the testes.

Ovarian Cycle

The monthly cycle of egg development, ovulation, and luteal phase regulated by hormones.

Graafian follicle

The mature ovarian follicle that releases the egg during ovulation.

Luteinising Hormone (LH)

A hormone that triggers ovulation and the development of the corpus luteum secreted by the anterior pituitary gland.

Asexual Reproduction in Protists

Can occur through binary fission, multiple fission, or budding.

Fragmentation

A method of asexual reproduction where an organism breaks into pieces, each capable of growing into a new organism.

Parthenogenesis

A form of asexual reproduction where a female gamete develops without fertilisation.

Follicle-stimulating Hormone (FSH)

A hormone that stimulates the growth of ovarian follicles in females and sperm production in males.

Testosterone

A hormone primarily responsible for the development of male reproductive tissues and secondary sexual characteristics.

Gamete

A haploid cell that fuses with another haploid cell during fertilization to form a zygote.

Sertoli Cells

Cells in the testes that provide support and nutrition to developing sperm cells during spermatogenesis.

Primary Oocyte

The initial stage of egg cell development in females, which is arrested in prophase of meiosis I until ovulation.

Secondary Oocyte

An egg that has completed the first meiotic division but is arrested in metaphase of meiosis II until fertilization.

Menstrual Cycle

The monthly cycle in females that prepares the body for potential pregnancy, regulated by hormonal changes including estrogen and progesterone.

Corpus Luteum

The hormone-secreting structure that develops from the Graafian follicle after ovulation and plays a crucial role in maintaining pregnancy early on.

Inhibin

A hormone that inhibits the secretion of follicle-stimulating hormone (FSH) and plays a role in regulating gametogenesis.

Diploid

A cell or organism that contains two complete sets of chromosomes, one from each parent; the full number of chromosomes, found only in somatic cells.

Haploid

A cell or organism with a single set of unpaired chromosomes, typically found in gametes; half the number of chromosomes.

Asexual Reproduction

A mode of reproduction involving a single parent organism, resulting in offspring that are genetically identical to the parent.

Sexual Reproduction

A mode of reproduction that involves the combination of genetic material from two parent organisms, resulting in offspring with increased genetic diversity.

Fertilisation

The fusion of male and female gametes to form a zygote, leading to the development of a new organism.

External Fertilisation

Fertilisation of an egg by sperm outside the female body, often occurring in aquatic environments.

Internal Fertilisation

Fertilisation of an egg within the female body, providing protection to the developing embryo.

Binary Fission

A form of asexual reproduction in which a single organism divides into two identical daughter cells.

Conjugation

The direct transfer of DNA from one bacterium to another through a temporary junction.

Transduction

A process where a bacteriophage transfers DNA between bacterial cells.

Gene Manipulation

The process of altering the DNA of organisms to achieve desired traits, including techniques like selective breeding and genetic engineering.

Transgenic Organisms

Organisms that have been genetically modified to contain genes from other species, often used in research and agriculture.

Gene Technology

Methods used to manipulate genes for various applications, including genetic modification of organisms to improve agriculture or health.

Mendel's First Law of Segregation

During meiosis, the alleles segregate so that each gamete carries only one allele for each trait, allowing offspring to inherit one allele from each parent.

Mutations

Permanent alterations in the DNA sequence of a gene that can affect how a gene functions, either inherited or acquired.

Frameshift Mutation

A genetic mutation caused by the insertion or deletion of a nucleotide in the DNA sequence, disrupting the reading frame.

Pedigrees

Charts used to analyze the inheritance patterns of traits or conditions within a family, helping to determine genotypes and phenotypes.

Phenotype

The observable physical traits or characteristics of an organism, resulting from the interaction of its genotype and the environment.

Genotype

The genetic constitution of an individual, describing the specific alleles present in the organism.

estrogen

chemical messenger secreted by the follicles. stimulates growth of the uterine lining and suppression of FSH (negative feedback). crucial for development of female secondary sexual characteristics.

• as ___ levels rise towards menstrual cycle, a positive loop causes a surge in LH which triggers ovulation

corpus luteum

when the graafian follicle ruptures to release the egg, the leftover follicle which secretes progesterone. prepares and maintains the endometrial lining for implantation. degenerates after 14 days

ligase

enzyme which creates hydrogen bonds to bind two bases together

polymerase

enzyme which adds free floating nucleotides onto primer during DNA replication

primase

enzyme which adds an RNA primer to begin a process of DNA replication

helicase

enzyme which unzips a DNA strand to create a replication fork

leading strand

strand of DNA which replicates in a continuous manner towards the replication fork

lagging strand

DNA strand which replicates in a discontinuous manner away from the replication fork using okazaki fragments

spontaneous mutation

a mutation that occurs as a result of incorrect dna replication

induced mutation

a mutation that results from a mutagen