Biology 2025 exam flash cards

Flashcards for reviewing lecture notes on the digestive, circulatory, respiratory systems, taxonomy, viruses, prokaryotes, eukaryotes, plants, genetics, and evolution.

What is the main function of the digestive system?

To break down food and absorb nutrients

Mouth

Chews food, mixes with saliva

Salivary glands

Makes saliva with enzymes

Esophagus

Moves food to stomach

Stomach

Breaks down food with acid and muscles

Small intestine

Digests food and absorbs nutrients

Liver

Makes bile to break down fat

Gallbladder

Stores bile

Pancreas

Makes enzymes for digestion

Large intestine

Absorbs water, forms waste

Anus

Removes waste from body

What is ingestion and where does it happen?

Taking in food, happens in the mouth

What is digestion and where does it happen?

Breaking down food, happens in mouth, stomach, and small intestine

What are the four major groups of macromolecules/nurtients?

Carbohydrates, proteins, lipids (fats), nucleic acids

Where does chemical and mechanical digestion happen?

Mechanical - mouth and stomach. Chemical - mouth, stomach, small intestine

What is absorption where does it happen?

Taking nutrients into the blood, happens in the small intestine

What is digestion and where does it happen

Removing waste, happens in the large intestine and anus

What role does saliva play in digestion?

Starts chemical digestion of starch and softens food

What is bolus? How and where does it form?

A soft ball of chewed food, forms in the mouth

What is chyme? How and where does it form

A thick liquid mix of food and stomach acid, forms in the stomach

What is the role of the stomach in digestion?

Mixes and breaks down food with acid muscles

Why does the small intestine contain villi? What do they create?

To absorb nutrients better, they increase surface area

Where are most nutrients absorbed?

In the small intestine

What do the liver, gallbladder, and pancreas do in digestion?

Liver - makes bile. Gallbladder - stores bile. Pancreas - makes enzymes

What does bile do to fats?

Breaks them into smaller pieces

Name four digestive enzymes and what they digest

Amylase - carbohydrates, Protease - proteins, Lipase - lipids (fats), Nuclease - nucleic acids

What does the large intestine do

Takes in water and forms solid waste

What does the epiglottis prevent

Keeps food out of the windpipe (trachea)

What is the purpose of the circulatory system

To move blood, oxygen, and nutrients around the body

List the 3 main components of the circulatory system

Heart, blood and blood vessels

What is in blood? List all the functions that blood preforms

Red blood cells - carry oxygen, White blood cells - fight infection, Platelets - help stop bleeding, Plasma - carries nutrients, hormones, and waste

What are the major differences in strucutureal between arteries and veins?

Arteries - thick walls, carry blood away from the heart. Veins - thinner walls, have valves carry blood to the heart

Why do we need capillaries

Capillaries are tiny blood vessels where oxygen, nutrients and waste are exchanged between blood and body cells

What happens during the pulmonary circuit of blood flow?

Blood goes from the heart to the lungs to pick up oxygen and drop off carbon dioxide, then returns to the heart

What happens during the systemic circuit of blood flow?

Oxygen rich blood is pumped from the hear to the rest of the body to deliver oxygen and nutrients, then returns with waste and carbon dioxide

Why does the heart need its circulatory system (cardiac circuit)?

He heart is a muscle and needs oxygen and nutrients too! The coronary arteries supply blood to the heart itself.

Open and closed circulator systems - example of an organism with each type

Open circulatory system - blood is not always in vessels. Closed circulatory system - blood stays inside vessels

What is the purpose of respiration

To bring oxygen into the body and remove carbon dioxide

What is the purpose of cellular respiration

To use oxygen and glucose to make energy (ATP) inside cells

What role do capillaries and alveoli play in respiration

Alveoli are tiny air sacs in the lungs where oxygen enters the blood and carbon dioxide leaves. Capillaries surround the alveoli and carry the gases in and out of the bloodstream

Nasal cavity

Warms, moistens and filters air

Pharynx (throat)

Pathway for both air and food

Epiglottis

A flap that blocks food from entering the airway

Larynx

Makes sound, lets air pass into the trachea

Trachea

Main airway that carries air to lungs

Bronchi

Two main beaches from trachea to each lung

Bronchioles

Smaller branches inside the lungs

Alveoli

Tiny sacs where gas exchange happens

Aquatic vs terrestrial respiration

Aquatic animals (like fish) use gills to take oxygen from water. Terrestrial animals (like humans) use lungs to take oxygen from air

Biological species concept

Defines a species as a group of organisms that can interbreed and produce fertile offspring

Advantage of biological species concept

Emphasizes gene flow and reproducitive isolation

Disadvantage of biological species concept

Does not apply to asexual organisms or fossils

What is the phylogenetic species concept?

Defines a species as the smallest group sharing a common ancestor on a phylogenetic Tree

Advantage of the phylogenetic species concept

works for any organism using measurable traits or DNA

Disadvantage of the phylogenetic species concept

requires detailed genetic or morphological data, may split very similar populations

What is the morphological species concept?

Defines a species by shared physical traits and structures

Advantage of the morphological species concept

easy to apply in the field and to fossils

Disadvantage of the morphological species concept

Subjective, different researchers may disagree on which traits matter

What are the conventions of binomial nomenclature?

Two part latin name - genus. Both italicized (or underlined if handwritten)

Who was carols Linnaeus and why is he the “father of taxonomy”?

He developed the binomial naming system, Organized plants and animals into hierarchical groups, Laid the foundation for modern biological classification

How do you read a phylogenetic tree To determine relationships?

nodes = common ancestors, Branch length may indicate time or amount of change

Provisioning

Products like food, timber, medicine

Regulating

Climate control, water purification, pollination

Cultural

Recreation, aesthetics, spiritual value

What is the basic structure of a virus

All viruses have genetic material, A protein coat called capsid protects the genetic material, Some viruses also have an outer envelope made of lipids

What are the types of viruses based on genetic material.?

DNA viruses - use DNA as their genetic code. RNA viruses - use RNA instead

What is the lytic cycle

Virus enters a host cell, Takes over the cell and makes many copies of itself, The cell bursts (lyses) and releases new viruses, Happens quickly

What is the lysogenic cycle

Virus inserts its DNA into the host cells DNA, Stays hidden for a while, Can switch to the lytic cycle later and become active

What are the key structural features of archaebacteria and eubacteria?

Cell wall - protects the cell, Cell membrane - controls what goes in and out, Cytoplasm - jelly like fluid inside the cell, Ribosomes - make proteins, DNA - free floating genetic material, Flagella - for movement, Pili - short hairs for sticking to surfaces or sharing DNA

Main difference

Archaebacteria - live in extreme environments and have unique cell wall chemicals. Eubacteria - live almost everywhere else and have a different cell wall structure

What is binary fission?

Asexual reproduction where one cell copies its DNA and splits into two identical cells

What is conjugation?

A process where two bacteria exchange DNA through a plus, not reproduction, but adds genetic variation

What does “ubiquitous” mean?

Found everywhere, bacteria are in soil, water, air and even inside us

What is a mesophile?

An organism that lives in moderate temperatures

What is an extremophile?

An organism that lives in extreme conditions like high heat, acid or salt

Identify a eukaryotic cell

A cell with nucleus and organelles

What is the difference between animal-like, fungus-like and plant-like protists?

Animal-like protists move and eat, Fugue like protists decompose, Plant like protists photosynthesize

What is an amoeba?

An animal like protist that moves with psedopods and eats by engulfing food

What is a paramecium

An animal like protist that moves with cilia and eats using an oral groove

What is a euglena

A plant like protist that can photosynthesize and also move with a flagellum, can act like both plant and animal

Describe the theory of endosymbiosis and plant evolution from green algae

Eukaryotic cells formed when one cell swallowed another. Land plants evolved from green algae

Non-vascular (seedless)

Mosses, no veins or seeds

Vascular seedless

Ferns, have veins but no seeds

Gymnosperms

Cones, seeds not in fruit

Angiosperms

Flowering plant with seeds In fruit

What role did vascular tissue and seeds play in plant evolution?

Vascular tissue - lets plant grow tall and move water/nutrients, Seeds - protect baby plants and help spread to new places

Sessile

Stays in one place

Motile

Moves

Bilateral

One line splits body in two equal sides

Radial

Body parts in a circle

Asymmetrical

No symmetry

What is a notochord

A flexible rod in embryos that helps form the backbone in some animals

Ectoderm

Outer layer

Mesoderm

Middle layer

Endoderm

Inner layer

Coelomate

No baby cavity

Pseudocoelomate

Fake cavity

Coelomate

True body cavity

What is segmentation

Body made of repeating parts

Dermal

Outer covering