Cell Biology: Eukaryotes, Prokaryotes, and Genetics

Eukaryotes

Cells that have a nucleus and membrane-bound organelles (e.g. animal and plant cells).

Prokaryotes

Cells that do not have a nucleus or membrane-bound organelles (e.g. bacteria).

Animal Cells

Eukaryotic cells that lack cell walls and chloroplasts; typically round in shape.

Plant Cells

Eukaryotic cells that have cell walls, chloroplasts, and a large central vacuole.

Nucleus

Organelle that controls the cell and contains DNA.

Mitochondria

"Powerhouse" of the cell; produces energy through cellular respiration.

Chloroplasts

Site of photosynthesis; only in plant cells.

Ribosomes

Produce proteins; found floating in cytoplasm or attached to ER.

Endoplasmic Reticulum (ER)

Transports materials through the cell; Rough ER has ribosomes.

Golgi Apparatus

Packages and processes proteins and lipids.

Lysosomes

Break down waste and damaged organelles; contain enzymes.

Vacuoles

Storage of water, nutrients, and waste. Larger in plant cells.

Cytoplasm

Jelly-like substance where cell activities occur.

Cell Membrane

Controls what enters and exits the cell.

Cell Wall

Provides structure and support in plant cells.

Centrioles

Help in cell division in animal cells.

Chromosomes

Long strands of DNA wrapped around proteins; carry genetic info.

Chromatids

Each half of a duplicated chromosome.

Centromere

Point where two chromatids are joined.

Haploid

Cell with one set of chromosomes (e.g. gametes).

Diploid

Cell with two sets of chromosomes (e.g. body cells).

Mitosis

Type of cell division producing 2 identical cells.

Meiosis

Type of cell division producing 4 unique gametes.

Cytokinesis

Division of cytoplasm after mitosis/meiosis.

Gametes

Sex cells (sperm and ova) with half the chromosomes.

Zygote

Fertilised egg cell.

Somatic Cells

Body cells (not gametes).

Autosomes

Non-sex chromosomes (pairs 1-22 in humans).

Sex Chromosomes

Chromosome pair 23 (XX or XY).

DNA

Deoxyribonucleic acid; carries genetic instructions.

Double Helix

Shape of DNA; twisted ladder.

Nucleotides

Building blocks of DNA (sugar, phosphate, base).

Base Pairs

A-T and C-G; adenine-thymine and cytosine-guanine.

Triplet Code

Three bases that code for one amino acid.

Amino Acids

Building blocks of proteins.

Mutation

A change in the DNA sequence.

Point Mutation

Change in a single base.

Frameshift Mutation

Insertion or deletion that shifts the reading frame.

Gene

Section of DNA coding for a trait.

Allele

Different versions of a gene.

Dominant

An allele that always shows if present.

Recessive

An allele that only shows if both copies are recessive.

Genotype

Genetic makeup (e.g. Bb).

Phenotype

Physical traits (e.g. brown eyes).

Homozygous

Two identical alleles (BB or bb).

Heterozygous

Two different alleles (Bb).

Punnett Square

Diagram to predict genetic crosses.

Monohybrid Cross

A cross for one trait.

Dihybrid Cross

A cross for two traits.

Codominance

Both alleles show up equally (e.g. AB blood type).

Incomplete Dominance

Blend of both alleles (e.g. red + white = pink).

Carrier

Someone who has one recessive allele for a disorder but is not affected.

X-linked Inheritance

Traits carried on the X chromosome (e.g. colour blindness).

Variation

Differences between individuals due to genes and environment.