Terms to Know

Human Biology

study of contemporary human biological variation

Anthropology

human knowledge - biological/physical: study of human/primate variation

Scientific Method

Observation, hypothesis forming, hypothesis testing, theory development

Hypothesis

testable prediction or educated guess about how things work

Null Hypothesis

a default baseline statement claiming there is no effect, no difference, or no relationship between variables

Primary Literature

peer reviewed, read and critiqued by other scientist in field

Secondary Literature

describes, analyzes and interprets primare literature

Genetics

how traits and biological information are passed down from parents to childre

Epigenetics

study of chemical modifications to DNA that are associated with changes in the way genes are expressed

Prokaryote

microscopic, single-celled organism that does not have a distinct nucleus or other membrane-bound parts inside its cell

Eukaryote

contain a distinct, membrane-bound nucleus, own DNA (ribosome, mitochondria)

Organelle

a tiny, specialized structure inside a cell that performs a specific job

Nucleus

Control Center of the Cell

Mitochondria

powerhouse of the cell

Ribosome

tiny cellular structure that builds protein from amino acids

Chromosome

thread-like structure made of tightly wound DNA and proteins that lives inside the nucleus of a cell and carries your genetic information

Somatic cell

• All body cells

• Direct cell activity

• Diploid

• Human somatic cells contain 46 chromosomes

Gamete

• Reproductive cells

• Males: sperm

• Females: egg

• Provides cytoplasm, including mitochondria

• Transmit genetic information

Haploid

Human gametes contain 23 chromosomes

Diploid

two complete sets of chromosomes—one set from each biological parent.

Homologous pair

set of two matching chromosomes—one inherited from the mother and one from the father

DNA

instruction manual inside your cells that carries the genetic information used to build and run your entire body

Nucleotides

the basic building block and repeating unit (monomer) of nucleic acids like DNA and RNA

Adenine

building block of life that helps form DNA, RNA, and cellular energy.

Thymine

DNA building block

Guanine

DNA building block

Cytosine

DNA building block

Gene

sequence of DNA bases that specifies the order of amino acids in a protein

Transcription

process where a cell copies a gene's DNA sequence into a temporary RNA message called messenger RNA

Translation

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

RNA

single-stranded molecule in cells that acts as a messenger, carrying instructions from DNA to build proteins

mRNA

genetic molecule that carries instructions from your DNA to the part of the cell that builds proteins

tRNA

small molecule that acts as an adapter or delivery truck, carrying specific amino acids to the ribosome to build proteins

uracil vs thymine

uracil is used in RNA while thymine is used in DNA

Protein

a large, essential molecule made of smaller building blocks called amino acids

Process of DNA replication

1. Denaturation

2. Annealing

3. Extension

Mitosis

46 chromosomes (single) → Replication (46 double strands)→ Cell division (2 daughter cells, each containing 46 single stranded chromosomes)

Meiosis

46 chromosomes (single) → Replication (46 double strands split into 23) → First cell division (reduction) (2 daughter cells, each have 23 double stranded chromosomes) → second cell division (4 daughter cells each containing 23 single stranded chromosome)

Mutation

• Generates brand new genetic variation

• Most are found in DNA regions that don’t have a function (non-coding regions)

Random Assortment

random way chromosome pairs line up and separate during cell division, giving each new sex cell a unique mix of traits from both parents

Recombination

the process where pieces of DNA are broken and mixed to create new combinations of genes

Sexual vs asexual reporduction

Sexual reproduction involves two parents combining sex cells to create unique offspring, while asexual reproduction involves a single parent producing genetically identical clon

Sex

Observable physical characteristics that distinguish
two kinds of human beings, females and males,
need for reproduction”

Gender

refers to the social, cultural, and
psychological constructions that are imposed on the
biological differences of sex”

Allele

version of a gene (T) for tall and (t) for short

Complex vs Simple Trait

• Simple traits (a.k.a Mendelian traits)

Traits whose variations are controlled by different versions of a single gene

• Complex traits

Traits that are influenced by more than one gene or environmental factor

Genotype

combo of 2 versions of a gene allele that a person inherited

Dominance

a trait expressed in the presence of a different allele

Recessive

a trait not expressed in the presence of a dominant trait

Homozygous

having the same allele at the same locus on both chromosomes (TT, tt)

Heterozygous

having different alleles at same locus (Tt)

Punnett Square

simple grid tool used in biology to predict the probability that offspring would inherit specific genes and traits from parents.

ABO Blood Groups

3 alleles: A, B, O

Genotype |Antigen on RBC | ABO blood type (phenotype)

AA, |AO | A A

BB, | BO |B B

AB |A and B |AB

OO |None | O

Codominance

a genetic inheritance pattern where both versions of a gene (alleles) are fully and equally expressed in an individual

Human Genome Project

• Main Goal: Decode the roughly 3 billion chemical base pairs that make up human genetic instructions.

• Result: Successfully created a master "blueprint" of human DNA, making it freely available to scientists worldwide.

• Medicine: Helps researchers find genes linked to diseases, leading to better tests and targeted treatments.

• Biology: Shows that 99.9% of the DNA sequence is identical in all people, helping us understand human evolution.

Pedigree Chart

Diagram of mating and offspring in family over a span of generations

Autosome

any chromosome that is not a sex one

Sex chromosome

special pair of chromosomes that help determine the biological sex of an individual

Gonads

the primary reproductive organs that make sex cells (eggs or sperm) and sex hormones

Sex steroid

steroid hormone that controls sexual development, reproduction, and secondary sex characteristics

DSD (Differences of Sexual Development)

What determines biological sex?

• A person’s sex chromosomes?

• The multiple genes that control the development of the gonads?

• Genes that control sex steroid receptors?

DNA Methlation

Epigenetic marks- Modification at transcription level – methyl group attached to DNA molecule (typically at guanine and cytosine) and ends up suppressing or enhancing chemical components of DNA

Histone modification

Epigenetic mark: Modification at DNA structural level - Any addition one of those chemical groups to a histone which impacts the ease with which DNA unwinds – Sensitive to environmetal condtions

microRNA

Epigenetic mark- Modification at transcription level – tiny strands of RNA binds to section of DNA and make it difficult to use DNA as a template

Intergenerational epigenetic effects

happens when a parent’s life experiences—like stress, diet, or toxic exposures—change how their genes work without altering the actual DNA sequence, and pass those chemical tags directly to their children

Levels of regulation of gene expression

epigenetic, transcriptional, post-transcriptional, translational, and post-translational levels

Epigenetic marks

Features that are not directly governed by the genetic code that are found on a DNA molecule and regulate gene expression

– Sensitive to environmental conditions

Hox genes

encode homeodomain protein product which are transcription factors

Plasticity

occurs when individuals respond to their environment by changing their form or physiology

Developmental plasticity

occurs when individuals respond to their environment by changing their form or physiology- can result in permanent changes in adult phenotype

Taxon

is the science of naming, defining, and classifying groups of biological organisms based on shared characteristics (Charles Darwin)

Lamarck

an organism can pass on physical traits it acquired or developed during its lifetime to its offspring (Charles Darwin)

Competition for resource

The struggle between organisms for limited life-essential necessities—such as food, water, light, and territory—which drives natural selection because only the best-adapted survive. (Charles Darwin)

Binomial nomenclature

universal two-part naming system used in biology to give every species a unique scientific name

Descent from common ancestor

The biological principle that all living organisms on Earth share a single ancestral origin and diverged into different species over time through evolution. (Charles Darwin)

Extinction

The permanent disappearance of a species from Earth, occurring when the last living member of that species dies (Charles Darwin)

Species

as fixed, unchanging categories to dynamic, interbreeding populations that change over time (Charles Darwin)

Adaptation

physical or behavioral trait that helps a living thing survive and reproduce in its environment

Darwin

a British scientist who created the theory of evolution by natural selection

Natural Selection

1. There is biological variation in all species

2. # offspring > resources

3. Competition

4. Greater fitness = survive + reproduce

5. Environment determines what is beneficial

6. Traits are inherited and passed on

7. Variations accumulate in a population

8. Geographical isolation contributes to new species

Evolution

Change in the gene frequencies of a population over time

Modern Synthesis

Change in allele frequencies over time

Directional selection

natural selection where an extreme physical trait or phenotype is favored over all others, causing the population's traits to shift in that single direction over time.

Genetic drift

• An example of neutral evolution

• Founder effect

• Reduces genetic variation

Founder effect

the loss of genetic diversity that happens when a small group of individuals breaks away from a larger population to establish a new, isolated colony

Gene flow

• An example of neutral evolution

• Increases genetic variation in the population

Selectionist hypothesis

a foundational concept in immunology stating that the body pre-designs a massive variety of immune cells, and when a foreign invader enters, it "selects" the specific cell that matches it to multiply and fight the infection.

Neutral theory

most genetic changes at the DNA and protein level do not affect an organism's survival or reproduction,

Vertebrates

an animal that has a backbone or spinal column

Homologies

Similarities between organisms based on descent from a common ancestor

Analogies

Similarities between organisms based on common function – no assumed common evolutionary descent

Ancestral

belonging to, inherited from, or relating to family members who lived long ago. ex: five fingers

Derived

evolutionary group within the human lineage (hominins) that evolved new, unique traits that were not present in their ancestors Ex: having a chin, walking upright

Clade

a group of organisms that includes a single common ancestor and all of its descendants

Cladogram

branching diagram that represents the evolutionary relationships and common ancestry between groups of organisms

Intraspecific vs. interspecific variation

Intraspecific variation: differences between individuals of the same species

interspecific variation: differences between different species.

Mammalian characteristics

warm-blooded backboned animals that have hair or fur and feed their young with milk

Primate characteristics

defined by large brains, grasping hands with flat nails, and forward-facing eyes (ex: lemurs, monkeys, humans

Phylogenetic tree

diagram that shows how different living things are related through evolution

Biological species concept

group of organisms that can mate and produce healthy, fertile offspring with each other in nature (Charles Darwin)