Pewarisan Sifat Kelas 9 SMP (Part-1)
Summary
TLDRThis video explains why children resemble their parents by introducing the concept of genetics. It covers the structure of cells, chromosomes, and genes, and highlights how genetic traits are inherited. The video also introduces key genetic terms such as dominant and recessive genes, genotypes, phenotypes, and alleles. Using Mendelโs pea plant experiments as an example, it explains how traits are passed down through generations. The video emphasizes understanding genetic concepts to better grasp inheritance and ends with an invitation to explore more in future lessons.
Takeaways
- ๐งฌ The smallest unit of living organisms is the cell, and inside the cell is the nucleus which contains chromatin threads responsible for inheritance.
- ๐ Chromatin thickens to form chromosomes, and within the chromosomes are genes that play a key role in passing traits from parents to offspring.
- ๐ฌ The study of inheritance is called genetics, pioneered by Gregor Johann Mendel, also known as the Father of Genetics.
- ๐ฑ Mendel used pea plants in his research because they could self-pollinate and cross-pollinate, produced many offspring, and had distinct traits like height and seed shape.
- ๐ถ In genetics, 'parental' (P) represents the parents, and 'filial' (F) represents the offspring, with F1 for the first generation and F2 for the second generation (grandchildren).
- ๐ Genes come in dominant (uppercase letter) and recessive (lowercase letter) forms, with dominant genes masking recessive ones.
- ๐๏ธ Genotype refers to the genetic makeup that isnโt visible, while phenotype refers to observable traits influenced by both genes and the environment.
- ๐งฉ Alleles are pairs of genes on chromosomes, and hybridization refers to crossing two different varieties of organisms with distinct traits.
- โก Homozygous genotypes have identical alleles (AA or aa), while heterozygous genotypes have different alleles (Aa).
- ๐ Gametes, or reproductive cells, carry genetic information and can be either male (sperm) or female (ovum), with rules for determining their genetic makeup based on genotype.
Q & A
What is the smallest unit of life in living organisms?
-The smallest unit of life in living organisms is the cell.
What are chromatin threads, and what do they do?
-Chromatin threads are structures found in the cell nucleus that carry hereditary traits. They thicken and form chromosomes, which contain genetic material responsible for passing traits from parents to offspring.
Who is known as the father of genetics, and what was his contribution?
-Gregor Johann Mendel is known as the father of genetics. He discovered the principles of heredity through his experiments with pea plants, laying the foundation for the science of genetics.
Why did Mendel choose pea plants for his experiments?
-Mendel chose pea plants because they can self-pollinate and cross-pollinate, produce many offspring, have distinct traits (e.g., tall vs. short plants), and have a short growth cycle, allowing for quick results.
What are the two types of filial generations, and how are they represented?
-The two types of filial generations are F1, which represents the first generation (offspring), and F2, which represents the second generation (offspring of F1).
What is the difference between dominant and recessive genes?
-Dominant genes are those that mask the effect of recessive genes and are represented by capital letters. Recessive genes are masked by dominant genes and are represented by lowercase letters.
What is the difference between genotype and phenotype?
-Genotype refers to the genetic makeup of an organism, which is not visible externally, while phenotype refers to observable traits, which are influenced by both genetic and environmental factors.
What are homozygous and heterozygous genotypes?
-Homozygous genotypes consist of two identical alleles, either dominant (e.g., AA) or recessive (e.g., aa), while heterozygous genotypes consist of one dominant and one recessive allele (e.g., Aa).
What is a hybrid in genetics?
-A hybrid in genetics refers to the offspring resulting from the crossbreeding of two different varieties of organisms with contrasting traits.
How do you determine the gametes of a genotype in genetics?
-To determine gametes from a genotype, if the genotype is homozygous, the gamete will contain only one of the identical alleles (e.g., AA gives A). If heterozygous, both alleles are written separately (e.g., Aa gives A and a).
Outlines
๐ฌ Understanding Genetic Traits
This paragraph introduces the concept of genetic inheritance, explaining how children inherit traits from their parents. It begins by discussing cells, the smallest unit of living organisms, and how within cells, chromatin (later forming chromosomes) carries genetic material. Genes, the fundamental units of heredity, are crucial in passing traits from parents to offspring. The paragraph also introduces Gregor Johann Mendel, the father of genetics, and explains why he used pea plants for his experiments, due to their fast reproduction and easily observable traits.
๐ Key Terminology in Genetics
This paragraph delves into important genetic terms like 'parental' (denoted as P, meaning parent), and 'filial' (denoted as F, representing offspring), explaining the difference between F1 (first-generation offspring) and F2 (second-generation offspring or grandchildren). It also discusses 'genes,' distinguishing between dominant genes (which mask others, written in capital letters) and recessive genes (which are masked, written in lowercase). The concept of 'genotype' (the genetic makeup) is explored, with examples of homozygous and heterozygous genotypes. Finally, the paragraph explains 'phenotype' (observable traits) and introduces 'alleles' as pairs of genes in chromosomes.
๐ฑ Hybrids, Hybridization, and Gametes
This paragraph explains hybridization, where two organisms with different traits are crossed to produce offspring with desirable characteristics. It mentions Mendelโs work and connects it to reproduction in animals and plants. The concept of 'gametes' (reproductive cells such as sperm and eggs) is introduced, along with a simple rule for writing the genetic composition of gametes. It provides examples of how to determine the gametes from homozygous (same alleles) and heterozygous (different alleles) genotypes. The paragraph ends with examples to reinforce understanding of the concept and concludes by encouraging students to keep learning and stay motivated.
Mindmap
Keywords
๐กSel
๐กKromatin
๐กKromosom
๐กGen
๐กPewarisan Sifat
๐กDominan dan Resesif
๐กGenotip
๐กFenotip
๐กParental dan Filial
๐กHibrid dan Hibridisasi
Highlights
Children often resemble their parents due to genetic inheritance from both parents.
Inside cells, there are chromatin threads that carry hereditary traits, which eventually form chromosomes.
Genes, found in chromosomes, play the most significant role in inheriting traits from parents to offspring.
The study of inheritance is called genetics, and Gregor Mendel is known as the father of genetics.
Mendel conducted experiments using pea plants due to their ability to self-pollinate and cross-pollinate.
Pea plants were ideal for Mendel's research because they produced many offspring with contrasting traits such as tall vs. short stems.
Mendel's research introduced terms such as parental (P) for the parent generation and filial (F) for the offspring.
The F1 generation refers to the first generation offspring, and F2 refers to the second generation or the grandchildren.
There are two types of genes: dominant genes (written with capital letters) and recessive genes (written with lowercase letters).
Genotypes refer to the genetic makeup, which can be homozygous (same genes) or heterozygous (different genes).
Homozygous dominant genotypes contain two dominant genes, while homozygous recessive contain two recessive genes.
Phenotypes are the observable traits of an organism, such as skin color, hair type, and height.
Alleles are pairs of genes in chromosomes, such as a dominant gene paired with a recessive one.
Hybridization is the process of crossing two individuals with different traits, leading to hybrid offspring.
Gametes are reproductive cellsโsperm in males and ova in femalesโwhich carry the genetic information to the next generation.
Transcripts
Hai tahukah adik-adik Mengapa anak-anak
memiliki kemiripan dengan orangtuanya
yuk temukan jawabannya di video ini
[Musik]
masih ingatkah Bagian terkecil penyusun
tubuh makhluk hidup adalah Sel nah di
dalam sel terdapat inti sel yang
didalamnya terdapat benang-benang
pembawa sifat keturunan
dikenal dengan nama kromatin benang
kromatin ini nantinya akan menebal
membentuk kromosom kalau diamati lebih
mendalam ternyata didalam struktur
kromosom terdapat materi genetik yang
disebut gen gen inilah yang paling
berperan dalam pewarisan sifat dari
orang tua atau induk kepada anak-anaknya
ilmu tentang pewarisan sifat disebut
genetika orang yang pertama kali
menemukan konsep genetika yaitu bapak
gregor Johann sendok atau dikenal
sebagai bapak genetika
penyelidikan sifat pewarisan dalam
genetika dilakukan oleh Mendel dengan
memanfaatkan kacang ercis atau kacang
kapri ada beberapa alasan mengapa Mendel
menggunakan kacang ercis atau kapri
dalam penelitian yang dilakukannya
antara lain kacang ercis dapat bersifat
autotrof kami dan alogami adik-adik
masih ingatkah dengan kacang ercis dapat
melakukan penyerbukan sendiri dan dapat
pula melakukan penyerbukan silang
kemudian cepat menghasilkan keturunan
keturunannya pun banyak dengan varietas
yang kontras misalnya ada yang berbatang
tinggi ada yang berbatang pendek ada
yang letak Bunganya di ketiak batang ada
juga di ujung daun ada yang bentuk
polong yang halus eh ada juga yang
keriput dan masih banyak lagi perbedaan
ciri lain yang mencolok alasan
selanjutnya yaitu umur tanaman kacang
ercis cenderung pendek jadi
itu kan waktu lama untuk menunggu
berbunga dan berbuah Nah itulah alasan
Mendel menggunakan kacang ercis sebagai
bahan eksperimennya sebelum mempelajari
lebih mendalam tentang pewarisan sifat
adik-adik harus mengenal dan memahami
terlebih dahulu beberapa istilah-istilah
dalam ilmu genetika diantaranya parental
biasanya diberi lambang p besar parental
artinya induk atau orang tuanya filial
dilambangkan huruf F filial adalah
keturunan ada dua macam filial yang
harus adik-adik pahami ada F1 artinya
keturunan pertama maksudnya adalah
anak-anaknya sedangkan F2 artinya
keturunan kedua sama saja seperti
cucunya ingat ya F2 bukan berarti anak
kedua Tapi keturunan kedua atau anak
dari F1 jadi biasa kita sebut cucu
istilah selanjutnya adalah Gin di awal
kita sudah membahas sedikit tentang gen
gen adalah faktor pembawa sifat
keturunan dalam istilah genetika
terdapat dua macam gen yaitu gen dominan
dan gen resesif gen dominan adalah gen
yang menutupi atau yang menang biasanya
dituliskan dengan huruf kapital
sedangkan gen resesif adalah gen yang
ditutup atau kalah biasanya ditulis
dengan huruf kecil istilah berikutnya
adalah genotip genotip berupa gabungan
gen yang sifatnya tidak tampak atau
tidak terlihat dari luar biasanya
dilambangkan dengan gabungan huruf
tertentu genotip ada dua macam yaitu
genotip homozigot dan genotip
heterozigot
genotip homozigot dituliskan berupa
gabungan huruf yang sama persis misalnya
hak besar abshar atau ah kecil aku kecil
bisa sama-sama besar atau yuk sama-sama
huruf kecil untuk yang sama-sama huruf
besar disebut juga genotip homozigot
dominan sedangkan yang sama-sama huruf
kecil disebut genotip homozigot resesif
sedangkan genotip heterozigot dituliskan
berupa gabungan huruf yang tidak sama
ada huruf besar dan ada huruf kecil
misalnya a besar a kecil b besar b kecil
c besar c kecil dan seterusnya
selanjutnya lawan dari genotip adalah
fenotip fenotip adalah sifat-sifat yang
tampak atau terlihat biasanya
dipengaruhi oleh faktor lingkungan
misalnya warna kulit jenis rambut tinggi
badan bentuk hidung mata dan lain-lain
ada lagi istilah alel-alel adalah
pasangan Gen di dalam kromosom-kromosom
a Contohnya seperti yang tadi ada besar
aku kecil artinya a besar berpasangan
atau searle ldengan a kecil istilah
selanjutnya ada hibrid dan hibridisasi
kalau hibrid adalah hasil persilangan
antara dua individu yang mempunyai sifat
beda sedangkan hibridisasi adalah
mengawinkan dua jenis makhluk hidup yang
berbeda varietas dan memiliki
sifat-sifat yang unggul Masih ingatkah
video sebelumnya tentang teknologi
reproduksi hewan atau tumbuhan kalau
lupa bisa disimak lagi ya istilah
terakhir adalah gamet-gamet adalah sel
kelamin bisa sel kelamin jantan atau
sperma dan sel kelamin betina atau ovum
masih membahas tentang game dalam ilmu
genetika adik-adik harus bisa menuliskan
lambang gamet dari setiap genotip yang
diketahui ketentuannya sangat mudah kok
jika berasal dari genotip homozigot maka
penulisan gametnya cukup dipilih satu
huruf dengan genotip tersebut tapi jika
berasal dari genotip yang Hero zigot
maka gametnya harus ditulis dari kedua
huruf notifnya tapi harus dipisah ya
tidak boleh digabung lagi agar lebih
memahami perhatikan contoh soal berikut
Tentukan gamet dari genotip a besar a
besar a besar a kecil dan aku kecil aku
kecil untuk genotip a besar a besar maka
gametnya hanya a besar karena a besar a
besar adalah genotip yang homozigot atau
hurufnya sama untuk genotip a besar a
kecil maka gametnya a besar dan aku
kecil Ingatkan ah besar aku kecil berupa
genotip heterozigot ada huruf besar dan
ada huruf kecil sehingga harus ditulis
kedua-duanya tapi dipisah ya bisa dengan
kata sambung dan bisa menggunakan koma
atau bisa ditulis terpisah atas dan
bawah untuk genotip a kecil a kecil maka
gametnya hanya a kecil
merupakan otip homozigot Hurufnya
sama-sama kecil Baiklah adik-adik
materinya sampai di sini dulu ya nanti
akan dilanjut lagi ke bagian2 Tetap
Semangat belajarnya ya terima kasih
wassalamualaikum warahmatullahi
wabarakatuh
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