Cell Biology and Bioenergetics Flashcards

A collection of vocabulary flashcards covering cell structure, organelles, cellular respiration, photosynthesis, cell division, and transport mechanisms based on the lecture notes.

Cell

The basic unit of all living things. Every organism is made up of one or more cells.

Cell membrane (plasma membrane)

The outer barrier of a cell that surrounds and protects it, controlling what enters and leaves the cell. All cells have one.

Cell wall

A stiff, rigid outer layer that surrounds the cell membrane in plants, fungi, and some bacteria, providing extra support and protection. Not found in animal cells.

Cytoplasm

The jelly-like substance inside the cell membrane that fills the cell and contains all the other organelles.

Cytosol

The clear, watery fluid portion of the cytoplasm in which organelles are suspended.

Organelle

A specialized structure inside a cell that performs a specific function, such as the nucleus, mitochondria, or chloroplasts.

Nucleus

The "control center" of the cell containing the DNA (genetic material), directing all cell activities.

Chromatin

The combination of DNA and proteins found in the nucleus; the uncondensed form of chromosomes.

Chromosome

A tightly packaged structure made of DNA and proteins that carries genetic information and becomes visible during cell division.

Ribosome

Tiny structures that make proteins; they can float freely in the cytoplasm or attach to the endoplasmic reticulum.

Endoplasmic reticulum (ER)

A network of folded membranes inside the cell. The rough ER has ribosomes and helps make proteins; the smooth ER lacks ribosomes and helps make lipids.

Golgi apparatus

An organelle that packages, modifies, and ships proteins and other materials to where they are needed in or outside the cell.

Mitochondrion (plural: mitochondria)

The "powerhouse" of the cell that converts food energy into ATP through cellular respiration.

Chloroplast

The organelle in plant and algae cells where photosynthesis takes place, containing the green pigment chlorophyll.

Vacuole

A large, fluid-filled sac inside cells that stores water, nutrients, or waste products. Plant cells typically have one large central vacuole.

Cytoskeleton

A network of protein fibers inside the cell that gives the cell its shape, helps it move, and provides internal organization.

Flagella

Whip-like tails that help some cells move, found in both prokaryotic and some eukaryotic cells.

Cilia

Short, hair-like structures on the surface of some cells that help with movement or sweeping materials across the cell surface.

Cellular respiration

The process by which cells break down glucose to release energy in the form of ATP, requiring oxygen and producing carbon dioxide and water as waste.

ATP (adenosine triphosphate)

The main energy-carrying molecule in cells that powers cellular activities like a rechargeable battery.

ADP (adenosine diphosphate)

The molecule formed when ATP loses a phosphate group and releases energy; it can be recycled back into ATP.

Glucose

A simple sugar with the chemical formula $C_6H_{12}O_6$, serving as the main fuel for cellular respiration.

Aerobic respiration

Cellular respiration that requires oxygen to produce ATP.

Anaerobic respiration

Cellular respiration that does not require oxygen.

Glycolysis

The first stage of cellular respiration occurring in the cytoplasm, splitting one glucose molecule into two pyruvate molecules to produce a small amount of ATP without oxygen.

Krebs cycle (citric acid cycle)

The second stage of aerobic respiration occurring inside the mitochondria, breaking down pyruvate and releasing energy captured in electron carriers like NADH and FADH₂.

Electron transport chain (ETC)

A series of proteins in the mitochondria that pass electrons to release energy used to make large amounts of ATP.

NADH

An electron carrier molecule that shuttles high-energy electrons from glycolysis and the Krebs cycle to the electron transport chain.

FADH₂

An electron carrier molecule that delivers electrons to the electron transport chain.

Fermentation

A type of anaerobic respiration allowing ATP production without oxygen, including lactic acid fermentation in animals and alcoholic fermentation in yeast.

Chemical equation for cellular respiration

$$C_6H_{12}O_6 + 6 O_2 \rightarrow 6 CO_2 + 6 H_2O + \text{ATP}$$

Photosynthesis

The process by which plants, algae, and some bacteria use light energy to convert carbon dioxide and water into glucose and oxygen.

Autotroph

An organism that makes its own food, such as plants through photosynthesis.

Heterotroph

An organism that cannot make its own food and must consume other organisms for energy, such as animals.

Chlorophyll

The green pigment in chloroplasts that absorbs light energy for photosynthesis.

Light-dependent reactions

The first stage of photosynthesis requiring sunlight, where water is split, oxygen is released, and energy is stored in ATP and NADPH.

Calvin cycle (light-independent reactions)

The second stage of photosynthesis that uses ATP and NADPH to convert carbon dioxide into glucose without directly requiring light.

Thylakoid

Disc-shaped, membrane-bound sacs inside chloroplasts where light-dependent reactions occur; stacks are called grana.

Stroma

The fluid-filled space inside chloroplasts surrounding the thylakoids where the Calvin cycle takes place.

Photosystem

A cluster of proteins and pigments in the thylakoid membrane that captures light energy and converts it to chemical energy.

ATP synthase

An enzyme that produces ATP by adding a phosphate group to ADP using energy from a proton gradient.

NADPH

An electron carrier molecule produced in light reactions that provides energy and electrons to the Calvin cycle for glucose synthesis.

Chemical equation for photosynthesis

$$6 CO_2 + 6 H_2O + \text{Light Energy} \rightarrow C_6H_{12}O_6 + 6 O_2$$

Cell cycle

The life cycle of a cell consisting of interphase (growth and DNA replication) and the mitotic phase (division).

Interphase

The longest phase of the cell cycle where the cell grows, carries out normal functions, and replicates its DNA.

Mitosis

Cell division producing two genetically identical daughter cells, used for growth and repair.

Meiosis

Cell division producing four genetically unique daughter cells (gametes) with half the number of chromosomes as the parent cell for sexual reproduction.

Cytokinesis

The final stage of cell division where the cytoplasm splits and the cell physically divides into two separate daughter cells.

Sister chromatids

Two identical copies of a chromosome joined together at the centromere, created during DNA replication.

Centromere

The region where two sister chromatids are joined together.

Diploid

A cell containing two complete sets of chromosomes, such as human body cells which have $46$ chromosomes.

Haploid

A cell containing only one complete set of chromosomes, such as human gametes which have $23$ chromosomes.

Homologous chromosomes

Pairs of chromosomes (one from each parent) carrying the same genes, but potentially different alleles.

Prophase

The stage of mitosis where chromosomes condense and become visible.

Metaphase

The stage of mitosis where chromosomes line up in the middle of the cell.

Anaphase

The stage of mitosis where sister chromatids separate and move to opposite ends of the cell.

Telophase

The stage of mitosis where two new nuclei form around the separated chromosomes.

DNA (deoxyribonucleic acid)

The genetic material that carries instructions for cell activities and is passed from parents to offspring.

RNA (ribonucleic acid)

A molecule that helps carry genetic information from DNA to the protein-making machinery of the cell.

Enzyme

A protein that acts as a biological catalyst, speeding up chemical reactions without being used up.

Diffusion

Movement of molecules from an area of higher concentration to lower concentration without requiring energy.

Osmosis

The diffusion of water across a selectively permeable membrane.

Active transport

Movement of substances across a cell membrane against their concentration gradient (low to high), requiring energy (ATP).

Passive transport

Movement of substances across a cell membrane from high to low concentration without using energy.

Cell theory

The concept that (1) all organisms are made of cells, (2) the cell is the basic unit of life, and (3) all new cells arise from existing cells.