Key Concepts in Cell Biology and Genetics

Cell membrane

Controls what enters and leaves the cell

Nucleus

Contains DNA and controls cell activities

Mitochondria

Site of cellular respiration; produces energy

Ribosome

Synthesizes proteins in the cell

Cytoplasm

Jelly-like substance where cell processes happen

Cell wall

Rigid layer outside plant cells providing support

Vacuole

Stores nutrients and waste in the cell

Lysosome

Contains enzymes to break down waste

Golgi apparatus

Packages and ships proteins

Endoplasmic reticulum

Transports materials within the cell

Chloroplast

Organelle where photosynthesis happens

Cilia

Tiny hairs that move substances across cell surface

Flagella

Tail-like structure for cell movement

Chromatin

Loosely coiled DNA inside nucleus

Prokaryote

Cell without nucleus

Eukaryote

Cell with nucleus

Diffusion

Movement of molecules from high to low concentration

Osmosis

Diffusion of water through a membrane

Selective permeability

Cell membrane allows some substances through

Phospholipid bilayer

Double layer forming cell membrane

Active transport

Movement of molecules against concentration gradient

Endocytosis

Cell engulfs material

Exocytosis

Cell expels material

ATP

Energy currency of the cell

Mitochondrial DNA

DNA found in mitochondria

Cytoskeleton

Provides cell shape and support

Gene

Segment of DNA coding for a trait

Chromosome

Tightly coiled DNA in the nucleus

Allele

Different versions of a gene

Genotype

Genetic makeup of an organism

Phenotype

Physical traits expressed

Homozygous

Two identical alleles for a trait

Heterozygous

Two different alleles for a trait

Dominant allele

Masks the effect of another allele

Recessive allele

Masked by dominant allele

Mutation

Change in DNA sequence

DNA replication

Copying DNA before cell division

Transcription

Making RNA from DNA

Translation

Making protein from RNA

Codon

Three bases of RNA coding for an amino acid

Enzyme

Protein that speeds up chemical reactions

Substrate

Molecule an enzyme acts on

Active site

Where substrate binds on enzyme

Denaturation

When enzyme loses shape and can't function

Coenzyme

Molecule helping enzyme function

Competitive inhibitor

Blocks substrate from binding enzyme

Non-competitive inhibitor

Changes enzyme shape

Photosynthesis

Process plants use to make food using sunlight

Chlorophyll

Green pigment that captures light energy

Light-dependent reactions

Convert light to chemical energy

Light-independent reactions

Use chemical energy to make glucose

Stomata

Pores on leaves for gas exchange

Thylakoid

Membrane where light reactions happen

Calvin cycle

Series of reactions making glucose

Cellular respiration

Breaks down glucose to release energy

Glycolysis

First step of respiration, breaks glucose into pyruvate

Krebs cycle

Produces electron carriers in mitochondria

Electron transport chain

Produces most ATP in respiration

Aerobic respiration

Respiration using oxygen

Anaerobic respiration

Respiration without oxygen

Fermentation

Anaerobic process making ATP

Lactic acid fermentation

Produces lactic acid in muscles

Alcoholic fermentation

Produces alcohol and CO2 in yeast

Homeostasis

Maintaining internal balance

Feedback loop

System that helps maintain homeostasis

Thermoregulation

Keeping stable body temperature

Hypothalamus

Brain part controlling homeostasis

Osmoregulation

Control of water balance

Endocrine system

Releases hormones for regulation

Nervous system

Sends and receives signals in body

Neuron

Nerve cell

Synapse

Gap between neurons

Neurotransmitter

Chemical messenger between neurons

Reflex

Automatic response to stimulus

Hormone

Chemical messenger in blood

Circulatory system

Transports blood and nutrients

Heart

Pumps blood

Artery

Carries blood away from heart

Vein

Carries blood to heart

Capillary

Tiny blood vessels for exchange

Red blood cell

Carries oxygen

White blood cell

Fights infection

Platelet

Helps blood clot

Blood pressure

Force of blood against vessel walls

Respiratory system

Exchanges gases in lungs

Lung

Organ for gas exchange

Alveoli

Tiny air sacs in lungs

Diaphragm

Muscle aiding breathing

Digestive system

Breaks down food for energy

Stomach

Breaks down food with acid

Small intestine

Absorbs nutrients

Large intestine

Absorbs

Liver

Produces bile

Pancreas

Produces digestive enzymes

Ecology

Study of organisms and their environment

Ecosystem

Community of organisms and environment

Producer

Organism that makes its own food

Consumer

Organism that eats others

Herbivore

Eats plants

Carnivore

Eats meat