SBI3U Midterm Vocabulary and Key terms List

Ranks of Taxonomy

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Binomial Nomenclature

Classification system of giving 2 word Latin names to each species.

Cladograms

Branching diagram that showcases evolutionary (cladistic) relationships between a number of species with a common ancestor

Principle of cladistics

As species evolve, they will acquire new traits

Derived Traits

newly evolved features, such as feathers, that do not appear in the fossils of common ancestors

Dichotomous Key

step by step approach to identify an organism using a series of paired descriptions that are unique from each other

Bacteria

single-celled organisms that lack a nucleus; prokaryote

- Mesophiles

- Standard energy production

- Cell walls made of peptidoglycan

Archaea

single-celled organisms that lack a nucleus; prokaryote

- Extremophiles

- Less standard energy production/ ways to feed itself.

Bacteria Nutrition

- heterotrophic: saprophytic or parasite

- autotrophic: chemosynthetic or saprophytic

- Some Facultative aerobic or anaerobic

- Some obligate aerobes

Archaea nutrition

- autotrophic: only chemosynthetic

- heterotrophic

- aerobic or anaerobic

chemosynthetic

having the ability to use the energy from chemical reactions to construct organic food molecules

Bacteria AND archaea

- No membrane-bound nucleus

- No organelles

- Single Celled

- Evolved from a common ancestor

methanogenesis

An energy-yielding metabolic process that produces methane. It is unique to archaea.

Virus

A tiny, nonliving particle that invades and then reproduces inside a living cell.

- contains strands of DNA and RNA with a protective protein coat

- NOT cells ( don't have cytoplasts, don't prod. waste)

Lysogenic cycle

1) Attachment: Virus attaches to host cell.

2) Insertion: Virus injects Viral DNA/RNA into host cell.

3) Provirus Formation: Viral DNA is spliced into Host's chromosome and becomes dormant.

4) Dormancy/Provirus Replication: Cell now including viral DNA, undergoes regular mitosis and hiding from immune systems because cell appears normal.

5) Stimuli Trigger: Environmental stressors (starvation, toxic chemicals, previous illnesses) trigger viral DNA to be spliced OUT of chromosome of host DNA and become active again.

- Days to years

Lytic cycle

1) Attachment: Virus attaches to host cell surface

2) Insertion: Viral DNA released into host cell, deactivates mRNA which usually provides instructions for proteins

3) Replication: The Viral mRNA takes over host cell machinery/ribosomes to translate VIRAL mRNA create VIRAL proteins

4) Assembly: New virus proteins are assembled

5) Lysis: Cell ruptures, releases viral proteins and is destroyed.

- 30 mins, immediate symptoms

Asexual reproduction

Pros:

- Rapid Population Growth

- Identical Bacterium production is beneficial in certain circumstances

Cons:

- lack of bacterium adaptation/ Genetic variation to better survive less favourable conditions

Sexual reproduction

Pros:

- Makes bacterium better adapted for unfavourable conditions

- Natural level of disease resistance through the evolution of bacteriophages and past instances of ___ production

Cons:

- More energy and time involved to reproduce

- Population rate slows down to come back to regular state

Genome

Entire set of DNA instructions found in a cell

- genetic blueprint of an ogranism

Gene

Fundamental basic unit of heredity

- Segment of DNA on a chromosome that instructs how to make a certain protein to code

Karyotype

Photograph of homologous pairs in a cell that is used for examining number, size, and shape of chromosomes

heredity

The passing on of traits from parents to their offspring

- determines various phenotypic traits expressed from the passed on genotypes of parents

Importance of Pedigrees

identifies inheritance patterns!!!

• Helps families identify the risk of transmitting an inherited illness

• Meticulous family records are helping researchers follow the inheritance of particular genes

Genetic recombination

Exchange of genetic material between 2 different chromosomes at the same region within the context of meiosis

Phenotype

An organism's physical appearance, or visible traits.

Genotype

An organism's genetic makeup, or allele combinations.

Homozygous

two identical alleles

dominant = AA

recessive = aa

Heterozygous

two different alleles, one dominant one recessive

Hemizygous

Only one copy of the gene

(one copy of the X chromosome- in men)

Monohybrid

Cross between only one trait with its dominant and recessive alleles.

Dihybrid

cross between TWO traits (w dom and recessive alleles)

Multiple Alleles

Fact that many different alelles exist within the population as a whole, but an individual only gets a few of them

Incomplete Dominance

Condition where neither allele is expressed completely

- neither conceal each other, thus creating a "3rd" phenotype which is a blend of both the dominant and recessive

- Usually happens in flowers

Codominance

When both alleles are expressed EQUALLY with NO blending- both are dominant

Sex-linked

traits/genes attached to the X chromosome only!

almost never found on Y

epistatis

- interaction between alleles in which one allele hides the effects of another allele

- gene at one locus on the chromosome alters the phenotypic expression of a gene at different locus

polygenic traits

characteristics that are influenced by more than one pair of genes

linked genes

- Genes located close enough together on a chromosome that they tend to be inherited together when homologous chromosomes come and go through recombination

Autosomal chromosome

22 chromosome pairs that control traits NOT related to gender--same in females and males.

Sex chromosomes

Chromosomes that determine the sex of an individual

AKA: X and Y chromosomes

Chromatid

one of two identical "sister" parts of a duplicated chromosome

Chromatin

granular material visible within the nucleus; consists of DNA tightly coiled around proteins

- DNA and proteins that help form chromosomes in the nucleus

Chromosomes

Package of coiled DNA wrapped around proteins- carries part of genetic code

Ribosomes

Structure (RNA + protein) involved in producing proteins by translating messenger RNA

Chiasma

Physical link/ point of contact between 2 chromatids belonging to a homologous chromosome

- where genetic recombination of the tetrads happens

Synapsis

Pairing of homologous chromosomes to form tetrads which facilitate genetic recombination

Tetrad

structure containing 4 chromatids that forms during meiosis

AKA a pair of 2 homologous chromosomes

Crossing over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Centrioles

Organelle that moves to opposite ends to control spindle fiber formation that separates and pulls apart chromosomes (meiosis 1) or chromatids (meiosis 2 and mitosis)

Gametogenesis

general term for the production of mature gametes like sperm and eggs through the combination of meiosis.

Somatic Cells

Any cells in the body other than reproductive cells or stem cells

Oogenesis

Process of producing female gametes (egg) in mammals.

diploid cell is called "oogonium"

1) go through mitosis and meiosis but stop at prophase 1.

2)Unequal division of cytoplasm: whichever cell contains more will continue to meiosis to form the viable egg

3) final stages of meiosis 2 will not go through unless egg is fertilized, at the end another polar body is made.

4) Egg will have large amt of nutrients to support zygote after fertilization- polar body degenerates (smaller one)

5) Haploid nucleus of egg fuses with haploid nucleus of sperm cell to complete the diploid zygote

Spermatogenesis

- Meiosis takes place in the testes

1) Diploid cell calls "spermatogonium"

2) Undergoes meiosis to form 4 haploid cells which further grow an mature

- Head = nucleus and other molecules

- midsection holds many mitochondria (energy source for cell)

- long tail for locomotion

Independent assortment

Independent segregation of genes during the formation of gametes

- Chromosomes sorting into different cells causing genetic variation independent of the other set of chromosomes.

Diploid (2n)

contain 2 copies of each chromosome

also known as the zygote

Haploid (n)

an organism or cell having only one complete set of chromosomes

also known as a gamete

Prophase

- chromatin condenses into chromosomes

- each one consists of 2 copies of one chromosome

- nuclear membrane breaks down

- spindle fibers form slowly from centrosomes that move to opposite poles of cell

Metaphase

- spindle fibers guide chromosomes to equator

- spindle fibers attach to centromeres

Anaphase

- centromere splits the sister chromatids

- separated chromatids now called chromosomes

- spindle fibers shorten to pull chromosomes to opposite poles of cell

- 1 complete set of chromosomes has been gather at each pole

Telophase + Cytokinesis

- Chromosomes unwind back into strands of chromatin

- spindle fibers break down

- nuclear membrane forms around new set of chromatin

- nucleolus forms within each nucleus

- Division of cytoplasm to create 2 daughter cells/daughter chromosomes

Non-disjunction

Change in Chromosome number

Why?

- Meiosis 1: tetrads fail to separate correctly

- Meiosis 2: sister chromatids fail to seperate

Prokaryotes

Single-celled organisms without a nucleus.

ex: bacteria and archaea

Bacterial Growth Curve

Deletion

piece of chromosome deleted, makes chromosome shorter

Duplication

piece of chromosome replicated (makes chromosome longer)

Inversion

Section of chromosome reattaches upside down during crossover

Translocation

fragment of one chromosome attaches to a different/nonhomologous chromosome.

Trisomy 21

Carrying an extra copy

- Down syndrome

- 1/800

Trisomy 18

- Edwards syndrome

- 1/18000

- intellectual and physical disability

- overlapped fingers at birth

trisomy 23 (XXY)

Kleinfelter's syndrome

- 1/1000

- Cannot produce sperm

- sexual immaturity

trisomy 23 (XYY)

- Jacobs syndrome

- 1/1000

- Taller than average

Monosomy 23

- Turner's Syndrome

- Affects only women

- Short

- webbed feet

- sexually underdeveloped

Key outcomes of meiosis

1) Genetic Reduction (2n -> n)

2) Genetic Recombination (variation)

Porifera

- Sponges

Symmetry: Asymmetrical

Tissue Layers: None

Body Cavity: None

Digestive System: Filter feeding through pores

Circulatory System: None

Nervous System: Simple/None

Skeleton Type: Spicules or spongin

Reproduction: Sex/Asex

Locomotion: Sessile (non motile as adults)

Habitat: Marine and some f.w

Cnidaria

Jellyfish, Coral, Hydra

Symmetry: Radial

Tissue Layers: DIploblastic

Body Cavity: None

Digestive System: Gastrovascular cavity (1 opening)

Circulatory System: None

Nervous System: Nerve net

Skeleton Type: Hydrostatic (water inside)

Reproduction: Budding + sexual

Locomotion: Pulsating/Drifting

Habitat: marine (some f.w)

Platyhelminthes

Flatworms

Symmetry: bilateral

Tissue Layers: Triploblastic (3)

Body Cavity: None

Digestive System: Gastrovascular cavity

Circulatory System: None

Nervous System: nerve cords and ganglia

Skeleton Type: Hydrostatic

Reproduction: Hermaphroditic (both parts) - sexual

Locomotion: Cilia or muscle contraction

Habitat: Aquatic or Parasitic

Nematoda

Round worms

Symmetry: bilateral

Tissue Layers: Triploblastic

Body Cavity: None (fake one though!)

Digestive System: Complete tract

Circulatory System: None

Nervous System: Nerve ring inside and cords

Skeleton Type: Cuticle (weird ahh covering)

Reproduction: Mostly sexual

Locomotion: Whip like movements

Habitat: Parasitic, aquatic, terrestrial

Annelida

Segmented Worms

Symmetry: Bilateral

Tissue Layers: Triploblastic (3)

Body Cavity: YES!!!!

Digestive System: Complete tract

Circulatory System: Closed

Nervous System: Ventral nerve and simple brain

Skeleton Type: Hydrostatic w segmentation

Reproduction: Sexual (some asex)

Locomotion: Muscular movement using microscopic legs (setae)

Habitat: Marine, fresh, terrest

Mollusca

Snails, squid, clams

Symmetry: Bilateral

Tissue Layers: triploblastic

Body Cavity: YES!

Digestive System: Complete tract

Circulatory System: Open or Closed

Nervous System: Nerve cords + ganglia

Skeleton Type: Calcium carbonate shell or internal support

Reproduction: Mostly Sexual

Locomotion: Muscular foot or Jet propulsion

Habitat: Marine, fresh, terrest.

Arthropoda

Insects, Crustaceans, Spiders

Symmetry: Bilateral

Tissue Layers: Triploblastic

Body Cavity: YES!

Digestive System: Complete tract

Circulatory System: Open

Nervous System: Brain, Ventral nerve cord, Complex sense organs

Skeleton Type: Exoskeleton made w Chitin

Reproduction: Sexual

Locomotion: Jointed Limbs

Habitat: Marine, f.s, terrest

Echinodermata

Starfish, Sea Urchins

Symmetry: Bilateral as larvae, but radial as adults

Tissue Layers: Triploblastic

Body Cavity: YES

Digestive System: Complete tract

Circulatory System: WATER vascular system (no blood)

Nervous System: Nerve ring + radial nerves

Skeleton Type: Endoskeleton made instead with calcium carbonate

Reproduction: Sexual

Locomotion: Hydraulic tube feet (bec water)

Habitat: Marine EXCLUSIVELY

Chordata

Fish, Humans, Birds (mainly vertebrates)

Symmetry: Bilateral

Tissue Layers: Triploblastic

Body Cavity: YES

Digestive System: Complete tract

Circulatory System: CLOSED

Nervous System: Brain, DORSAL nerve cord, complex senses

Skeleton Type: ENDOskeleton

Reproduction: Sexual

Locomotion: Muscles, fins, limbs

Habitat: marine, fresh, terrestrial